02:21 The angry woman is the figurehead of the Cutty Sark. "Cutty sark" is Scots for "torn shift". It's a reference to the Robert Burns poem "Tam O'Shanter", in which Tam and his horse are pursued by an angry, half-dressed witch. The witch grabs at the horse's tail just as rider and mount are crossing a stream. Tam and the horse escape and the witch is left holding the horse's tail.
@@ExpeditionYachts The bow and the stern were the traditional areas of decoration on ships of the line 🇬🇧 see HMS Victory the original fast battleship.. 16knts ... You also had HMS Warrior sail and Steam but all iron hull. The amount of time and cost was a major issue for the naval boards purse so Sam Pepe's i believe commented on it and the need to concentrate costs and deadlines in the face of wars on two fronts the Colonies and against the French ..then against slavers and building the empire.
Adding to Roland's excellent comment, the witch figurehead on the Cutty Sark is named Nannie, and the ship is indeed named after the short nightdress or shift that she's wearing. Figureheads were considered to be(or represent) the soul of the ship, and since vessels are generally referred to as "she" most of the figureheads are female. However maritime superstition has it that a fully clothed woman on a ship brings bad luck, hence why the female figureheads are always partially clothed or naked.
I have seen green water, come over the open bridge of my first ship USS Newport News (CA-148). A cyclone at sea is never fun, you brought back memories.
First of all I would like to say thank you for a great informative and even somewhat educational episode. I commend your courage to show super-yachts in such situations given you also broker them. Yet I would hope that potential buyers and sellers will appreciate your honesty, because obviously, when spending that much money on a vessel, I am guessing building up trust and having a reputation you can be trusted is essential. I've actually had a lecture on Bow design here on TH-cam, not sure if it was MIT's open courseware or another university, I cannot remember its quite a while ago, I do remember the lecture though because it was very interesting. Anyway, bow design is a huge and very interesting topic that includes several scientific disciples. You mentioned that too. Anyway the one thing I wanted to add is that all bow-shapes have pros and cons and for now at least, there is no one bow fits all. So your advice to future owners to really think about how, when and where they will be using their vessel in relation to their choice of bow, I believe is very good advice indeed. I have a personal advice or rather half-joke to add, if you don't like the sea, consider buying a private jet instead ;-)
Thanks for your thoughtful note, John. If more time and money was spent of seakeeping, rather than what color antiqued-leather to put on the walls, we would see more of these innovations in the yacht sector.
I used to laugh in the bay of biscay, north sea during winter, during Katrina our gas carrier was at the seas mercy, cape of good hope always kept us on our toes. What can we do other than enjoy the sheer beauty of the rough seas. The flared bow is good for the growlers and ice laden waters of the saint Lawrence River. The Trip from Ghana to Montreal used to be quite eventful on a 110,000 MT DWT bulk carrier fully loaded enroute to montreal and 22,000 MT Lightship on the way back to Takoradi( Ghana). Those sweet days listening to BBC Radio in the mid Atlantic at 04:00 a.m. Land is quite boring.
I saw another YT post re X-bows. The video you have aaa about 6 minutes of two ships in identical conditions, had essentially the same HP available. The X-bow ship could maintain about 13 knots, the conventional ship 7 knots.
Just sailed on the new Celebrity Ascent and the bow design peaked my curiosity. I noticed more side roll than older ships. Great explanation, thank you.
Captains of the various new designs talk about peculiar 'motion', excessive bow spray, and getting 'knocked sideways'. I always look to see what the commercial operators are doing as they are most mindful of crew comfort, safety and economy - not necessarily in that order.
Since all of these are my designs, let me give you a brief run-down. Multi-hull vessels have a shallow draft, so they are more prone to capsizing than to sinking. Mono-hull vessels have a deep draft to avoid capsizing, so are more prone to sinking. 1- The Ulstein X-Bow will survive storms, but it has to be a large ship, so beam waves don't capsize it. You do realize that it has an enormous free-board for beam waves to hit. 2- The Axe-Bow doesn't have good storm resistance, unless it is also very large. It needs to have a large beam, a large-freeboard(which will raise issues with beam waves), and a wedge that broadens abruptly toward the mid-ship to survive storms. You can, of course, perfect the design, but an X-Bow is much easier to implement. 3- A well-designed trimaran has good storm resistance and fuel economy, provided the structure is strong enough for it to not break. 4- A flared bow is the easiest to implement for cheap vessels. The Norwegian patrol boat, which I chose to convert to my expedition yacht, has a bow that is primarily an axe, but flares at the top, it also is rounded on the edges, not angular, so can even somewhat deflect beam waves. Behind the mid-ship, it is flat, so beam waves can flow over it. It's possible to have hybrid shapes. The Trimaran is the most economical, but the beam can be large for narrow ice-passages. The X-bow is good for those who have a lot of money to spend on operating expenses. The Axe-bow is for those who want speed and a smooth ride, but can't afford the operating expenses of the X-bow. The flared bow is for those who are running on a tight budget and need a mono-hull for narrow polar-passages. The spherical/oval Ghost ship is like a buoy, so is impossible to sink. It can also hydrofoil at high speeds, but requires careful design and operation. The Stiletto multi-hull can rollover and still not sink, but requires enormous power. None of these are suitable for yachts because they don't have much usable open-deck space. Iterations on all three are possible for those who want to optimize specific aspects.
The "very angry woman" at 2:12 is "Cutty Sark". This witch was from the poem "Tam O'Shanter" by Robert Burns. As Cutty Sark chases Tam O'Shanter, she grabs and rips off the tail of his horse just as he escapes over a river. She is depicted in the figurehead holding the tail of Tam's horse. It's not a scalp.
Bow shape would not much of be a factor for light ice, but to be a 'breaker', the vessel needs a bow that can ride up on the ice and then crush it with its weight.
There is the length of the wave, the length of the ship, and the speed of the ship. Isn't there an optimal speed where a ship goes the " most comfortable " way? Sure it may not be the fastest but still. Can such a speed be calculated easily or is it already known, just that i haven't heard of it?
Perhaps an expert can comment. My understanding is that there is something called 'hull speed' and a vessel does not want to go much over that speed, no matter how much horsepower you throw in it.
en.wikipedia.org/wiki/Hull_speed hull speed for 60 m3ters is 18.8 knots Wave making resistance depends dramatically on the general proportions and shape of the hull: many modern displacement designs can easily exceed their 'hull speed' without planing. sq root of water line in meters x 2.43 = hull speed in knots
Wonderful content Paul! Question for you - isn’t that an ancient boat idea? That long sharp bow? I know on a smaller scale but - when you see these huge ships - it must be the same thinking. Right?!
Not because it was not known before but because poor transition abilities for manufacturers and ingeneers. It is like to make new energy sources while people are scared bc of unknown and scared of faults. Not so strong position in life it is 😊
I was aboard the, briefly pictured in the video , Steam Ship Delphine before it was restored, but it was still in fantastic shape. It is hard to see , and out of focus in the video, but behind the bridge cabin, is a large matching mahogany observation room, with big heavy roll down windows all around. All the built in bench seating, including the matching chairs around the central table, were upholstered in leopard skin. a theme that continued with good sized padded leopard skin insets on the walls, that separated the windows equidistantly as they went intirerly around the room, save for the entrance doors. the ship was used for a central command of all western navel planning in the Atlantic during WW2. Down below is a triple expansion steam engine, all filigree engraved on almost every surface of the black metal used in the engine, trimmed in decorative brass, in the art deco streamline modern style, lots of curls on the decorative brass used on the corners and to frame some of the brass mechanical gear. like something out of a Jules Vernes movie set, except all functional , a very pretty effect. The mahogany paneled guest rooms were not huge, but the bathrooms were all done in small hexagonal white tile, in the now antique style of the day, save for the overhead. The floor tile continued up to form the bath tub, as it did along the walls and the sink support, I don't remember if the sink was also all tile , but it probably matched the bathtub . The deck sailors slept forward , in hammocks spread between the steel ribs of the bow, next to the un-insulated steel of the hull, and below the deck storage rooms. Almost forgot, the davits pictured on top , here looking like they are for a white hulled lifeboat, were used for matching mahogany Chris craft power boats, with one tender open, and the other a cabin cruiser.
Thanks for these recollections! When I saw her in Portugal, they still had the matching tenders in the shed, and they were being offered with the vessel. However, I don' t know if they are still onboard now.
All of these new hulls are based on the following proposals of mine from 2003: 1- The Trimaran: The problem with a catamaran was that it couldn’t split large frontal waves into multiple angular, horizontal and vertical components to reduce the impact of the wave, so the central hull of a Trimaran could lead the other two hulls to split a large wave before it could hit the main hull. The central hull also had to be placed well ahead of the lateral hulls to protect the lateral hulls from the wake generated by the central hull. This meant that the central hull, much like a spoon-shaped ice-breaker, could also climb on top of ice packs, pull the other two hulls over, and break the ice-pack with the weight of the vessel, not the force of the impact. Three separate engines in the three hulls could also optimize steering to do away with the need for bow thrusters or azimuth pods. The shapes of the hull were convex wedges below and above the waterline, so that the convex wedge below the waterline had a pronounced and deep taper for it to spring back from plunges from high crests into deep troughs, whereas the convex top would break waves smashing on top into multiple angular components to reduce the vertical forces pushing the vessel down. The hull shape at bow, stern, and the sides was also convex, like semi-spherical wedges, to break bow, stern and beam waves into angular, horizontal, and vertical components to reduce the impact on the ship. These would also break and deflect beam and stern waves. Small ships could also have the tips of the lateral hulls designed as Anhedral wings, like those on the Harrier or C-17 aircraft, so, at slow speeds, these could serve as anchors to prevent the ship from tipping over to capsize, whereas at high speeds, these would generate lift and rise, just like aircraft, to have the lateral hulls hydrofoil at high speeds to reduce the drag. You can think of this anhedral wing as an advanced iteration of the paravane and the drogue: www.mirtoart.com/image/I0000hgdYnQv9INU The following ships were based on this concept of mine. a- The Independence Class littoral vessel: en.wikipedia.org/wiki/Independence-class_littoral_combat_ship b- The Adastra Trimaran: robbreport.com/motors/marine/custom-hi-tech-trimaran-yacht-adastra-hits-the-market-for-12-million-2857532/ 2- Mono-hull Vessels with Convex Tops and Bottoms: These are different partial iterations of the wedged trimaran and spherical hulls for mono-hull vessels. a- The Zumwalt Class destroyer is an exact mono-hull implementation of the Independence Class trimaran hull: www.usni.org/magazines/proceedings/2018/october/handling-zumwalt-class-destroyer b- The Ulstein X-bow vessel is a spherical implementation of the convex top and bottom wedge hulls, with a very large free-board and a much shallower draft: www.boatdesign.net/threads/a-little-help-with-x-bow-ulstein.37365/ c- The Damen Sea-Axe is an angular implementation of the convex hull with a smaller freeboard and a deeper draft: www.superyachttimes.com/yacht-news/amels-sells-first-67m-sea-axe-fast-yacht-support-vessel Vessels need to be able to spring back from deep troughs; for this, you need a long taper. This taper can be a shorter V-taper below the waterline or a much higher inverted-V taper above the waterline. The Axe-Bow uses the former, whereas the X-bow relies on the latter. 3- The Sharp-Keel, Rollover Vessel: A well-designed vessel can survive a wave-height 60% that of its length to prevent pitch-poling. This design relied on a long-bow, which was essentialy a blade-like keel, to keep the boat steady, as it sliced or axed through the wave. It had to be long enough for it to cross the wave and help haul the mid-ship across the wave before the boat pitch-poled. The bow behind the blade-like keel, broadened, as a wedge, so it would spring back from dips into deep troughs. The boat was kept long and flat to optimize the hull-speed, and so that beam waves could flow over the boat without capsizing it. A partial trimaran was required to minimize capsizing and optimize hull efficiency. This isn’t very different from the Independence Class trimaran in concept, but is much smaller, so can rollover and self-right. A larger vessel would hurt the crew if it rolled over to self-right. Since this was a boat, not a ship, it could also roll-over and self-right. The following boats are based on this concept: a- The Thunder Child: www.bairdmaritime.com/work-boat-world/maritime-security-world/non-naval/thunder-child-ii-demonstrator-high-speed-patrol-boat-for-all-weather-conditions/ 4- The Spherical or Oval Vessel: The most radical of my proposals was a spherical boat that could roll-over in the ocean, like a buoy or a ball, because a sphere would deflect the forces into different angular, horizontal and vertical components to reduce the force of impact of a wave. A sphere, because of the taper, would also rise back, like a spring, so remain buoyant. This design of mine had the inner structure like that of the gyroscope, connected to the outer hull with pivots, so the crew would remain horizontal even as the outer hull rolled over. The oval shape was a more practical iteration on the sphere for higher speeds. These also had rectangular cavities at the bottom and top, so the hull would work as a displacement hull at low speed and in stormy conditions, plane at higher speeds, and eventually hydrofoil at very high speeds. The following vessels are based on this concept of mine. a) The US Special Forces Ghost Vessel was based on an identical implementation of this concept of mine: interestingengineering.com/meet-the-ghost-the-boat-that-sails-through-bubbles b)These SWATH catamaran vessels are also based on a partial implementation of the same concept. Since most of the turbulence is on the surface of the ocean, these slice through the turbulence with narrow multiple hulls and incorporate small water-planing surfaces(wings) at the maximum depth of the hull to resist capsizing forces: dmsonline.us/smooth-sailing-pros-and-cons-of-a-swath-vessel/ c) The Stiletto vessel, also based on a partial implementation of the concept, is a multi-hull vessel without the deep planning surfaces: en.wikipedia.org/wiki/M80_Stiletto 5- The Flared Bow: This has been the traditional design for centuries, and has nothing to do with me. When I designed the earlier hulls in 2003, I was just 35 years old. Now, I’m 54, and feel the age, so, for myself, I’d either opt for the Alucia, the MMM or Karima, the Sea Wolf or Ithasca, or the Norwegian patrol vessel, the Scottish fisheries patrol vessel, the US T-AGOS vessel, or an offshore support vessel converted into an expedition yacht. All of these have flared bows because I want something cheap, off the market, and economical. I’m also too old to bother with designing new hulls. I want my expedition yacht to be able to carry the Gweduck amphibious aircraft and, yet, be economical to operate, so I would choose the flared bow.
Héllo , ultimately there is no good or bad Bow I think it all depends on the shape and size of boat you want!? and also maybe a certain comfort in the wave, right?
It all depends on the sea condition you are operating in- and that changes in a blink of an eye. The captains who operate these different vessels have strong opinions based on experience.
They are really. And if you follow the progress on those designs you’ll see they’ve started offering a matching stern shape making them even more like a traditional canoe of north america
One-day maybe. There really aren't many around- the military has probably done most of those builds as 'trials', and none of them really caught on, as far as I know. There may be some being built now for wind-farm maintenance.
You saw the figure head from the Cutty Sark clutching the hair ..😉 If your Rich or Powerful or just want to intimidate the locals .. Viking Dragon heads. ..and there's another off shore bow... And as for the reverse bow look at ancient Greek Triremes.. So in a word Yes.😉
From reading about the Xbow design. These were made for oil rig support vessels in the North Sea where the rear needed to be stable to transport large items in (rarely flat) high swell seas up to the oil rigs. They are now being used for offshore wind farms where you often have to service them especially in the winter where sea swells are the norm. Since many ferry ships have swing up bow doors as well to speed up boarding cars and trucks while others exit at the rear,. why don't we see more Xbow ferry ships considering their slow transit speeds and as on a schedule, the need to transit in bad weather where the slamming and rocking motion has an impact on passengers/cargo and the damage to the ship over time. Surely car carrying cargo ships would be an ideal Xbow customer. PLus it means the ship can transit faster and now slow down as much in bad sea states.
All true. The expedition cruise ships they have built report that they are extremely stable and sea-kindly for both crew and guests. But shipyards like to build what they know already, and they only adapt if the customers insist.
@@ExpeditionYachts Plus they don't look a stylish. I can see them selling on cruises into rough water - Alaska/Antarctica/Scandanavia/Japan or anywhere that passengers are not used to rough seas (indians?/Middle east?/Chinese?). If they can also cut fuel and emissions that might also drive adoption. Superyacht owners want to show off so its unlikely to gain much traction in the Med/Caribbean
Wonder if x-bow can be make to work in boats in 45-50 meters range. The go anywhere pocket explorer size. Haven't come across one built in that size and then again commercial boats that take that design doesn't necessarily come in those sizes either.
Hi Paul thanks again for the video. l sailed in the eighties on anchor handling supply vessels and also as towmaster on different trips and l also sail on a lot of sailing yachts l am a pensioner now but l think this new bow design is a big improvement not only for fuel consumption but also the slamming of the vessel will be a lot less so much more comfortable for the crew.
Ah yes- the crew. Owners and guests seldom make serious passages on motor yachts, and so it is the crew that endures bad seakeeping and excessive pitch and slamming. Unless you've been out there, you don't have a clue. Thanks for note.
@@ExpeditionYachts Was the sea and anchor helmsman on a Korean era us navy minesweeper. Yep been thru many a storm. no fun with green water over the bow.
This is great and all, but where are the vids of all of these X-bow and Axe-bow ships in extreme weather? One would think that a hull designed to cut through a wave rather than go over would be prone to "dive" into waves rather than slam into then rise over them. Unless these ships are being built as partial submarines, I would think diving into the base of a 30+foot wave would put an extreme force on the hulls as they pushed deeper into the wave.
@@ExpeditionYachts I was talking more on the notion of 40ft + waves, which I haven't seen a single ship of this design present in. I have seen a commenter on one of your other videos say they were the designer of the X-bow, and that it was great on very large ships in calm to choppy weather conditions, not storm force waves.
02:21 The angry woman is the figurehead of the Cutty Sark. "Cutty sark" is Scots for "torn shift". It's a reference to the Robert Burns poem "Tam O'Shanter", in which Tam and his horse are pursued by an angry, half-dressed witch. The witch grabs at the horse's tail just as rider and mount are crossing a stream. Tam and the horse escape and the witch is left holding the horse's tail.
Thank you for that history. I personally love the sailing ship figureheads and would like to see them make a comeback.
@@ExpeditionYachts
The bow and the stern were the traditional areas of decoration on ships of the line 🇬🇧 see HMS Victory the original fast battleship.. 16knts ... You also had HMS Warrior sail and Steam but all iron hull.
The amount of time and cost was a major issue for the naval boards purse so Sam Pepe's i believe commented on it and the need to concentrate costs and deadlines in the face of wars on two fronts the Colonies and against the French ..then against slavers and building the empire.
Adding to Roland's excellent comment, the witch figurehead on the Cutty Sark is named Nannie, and the ship is indeed named after the short nightdress or shift that she's wearing.
Figureheads were considered to be(or represent) the soul of the ship, and since vessels are generally referred to as "she" most of the figureheads are female. However maritime superstition has it that a fully clothed woman on a ship brings bad luck, hence why the female figureheads are always partially clothed or naked.
I have seen green water, come over the open bridge of my first ship USS Newport News (CA-148). A cyclone at sea is never fun, you brought back memories.
First of all I would like to say thank you for a great informative and even somewhat educational episode. I commend your courage to show super-yachts in such situations given you also broker them. Yet I would hope that potential buyers and sellers will appreciate your honesty, because obviously, when spending that much money on a vessel, I am guessing building up trust and having a reputation you can be trusted is essential. I've actually had a lecture on Bow design here on TH-cam, not sure if it was MIT's open courseware or another university, I cannot remember its quite a while ago, I do remember the lecture though because it was very interesting. Anyway, bow design is a huge and very interesting topic that includes several scientific disciples. You mentioned that too. Anyway the one thing I wanted to add is that all bow-shapes have pros and cons and for now at least, there is no one bow fits all. So your advice to future owners to really think about how, when and where they will be using their vessel in relation to their choice of bow, I believe is very good advice indeed. I have a personal advice or rather half-joke to add, if you don't like the sea, consider buying a private jet instead ;-)
Thanks for your thoughtful note, John. If more time and money was spent of seakeeping, rather than what color antiqued-leather to put on the walls, we would see more of these innovations in the yacht sector.
I used to laugh in the bay of biscay, north sea during winter, during Katrina our gas carrier was at the seas mercy, cape of good hope always kept us on our toes.
What can we do other than enjoy the sheer beauty of the rough seas.
The flared bow is good for the growlers and ice laden waters of the saint Lawrence River. The Trip from Ghana to Montreal used to be quite eventful on a 110,000 MT DWT bulk carrier fully loaded enroute to montreal and 22,000 MT Lightship on the way back to Takoradi( Ghana).
Those sweet days listening to BBC Radio in the mid Atlantic at 04:00 a.m.
Land is quite boring.
I saw another YT post re X-bows. The video you have aaa about 6 minutes of two ships in identical conditions, had essentially the same HP available. The X-bow ship could maintain about 13 knots, the conventional ship 7 knots.
More on this here: ulstein.com/innovations/x-bow/comparison-tests
Just sailed on the new Celebrity Ascent and the bow design peaked my curiosity. I noticed more side roll than older ships. Great explanation, thank you.
Captains of the various new designs talk about peculiar 'motion', excessive bow spray, and getting 'knocked sideways'. I always look to see what the commercial operators are doing as they are most mindful of crew comfort, safety and economy - not necessarily in that order.
Very interesting. Really liked the simulation.
Glad you liked it! I borrowed those from Ulstein and Damen. Fair Use.
"figureheads embodied the spirit of the vessel, offering the crew protection from harsh seas and safeguarding their homeward journeys."
Since all of these are my designs, let me give you a brief run-down.
Multi-hull vessels have a shallow draft, so they are more prone to capsizing than to sinking.
Mono-hull vessels have a deep draft to avoid capsizing, so are more prone to sinking.
1- The Ulstein X-Bow will survive storms, but it has to be a large ship, so beam waves don't capsize it. You do realize that it has an enormous free-board for beam waves to hit.
2- The Axe-Bow doesn't have good storm resistance, unless it is also very large. It needs to have a large beam, a large-freeboard(which will raise issues with beam waves), and a wedge that broadens abruptly toward the mid-ship to survive storms. You can, of course, perfect the design, but an X-Bow is much easier to implement.
3- A well-designed trimaran has good storm resistance and fuel economy, provided the structure is strong enough for it to not break.
4- A flared bow is the easiest to implement for cheap vessels. The Norwegian patrol boat, which I chose to convert to my expedition yacht, has a bow that is primarily an axe, but flares at the top, it also is rounded on the edges, not angular, so can even somewhat deflect beam waves. Behind the mid-ship, it is flat, so beam waves can flow over it.
It's possible to have hybrid shapes.
The Trimaran is the most economical, but the beam can be large for narrow ice-passages.
The X-bow is good for those who have a lot of money to spend on operating expenses.
The Axe-bow is for those who want speed and a smooth ride, but can't afford the operating expenses of the X-bow.
The flared bow is for those who are running on a tight budget and need a mono-hull for narrow polar-passages.
The spherical/oval Ghost ship is like a buoy, so is impossible to sink. It can also hydrofoil at high speeds, but requires careful design and operation. The Stiletto multi-hull can rollover and still not sink, but requires enormous power. None of these are suitable for yachts because they don't have much usable open-deck space.
Iterations on all three are possible for those who want to optimize specific aspects.
The "very angry woman" at 2:12 is "Cutty Sark". This witch was from the poem "Tam O'Shanter" by Robert Burns. As Cutty Sark chases Tam O'Shanter, she grabs and rips off the tail of his horse just as he escapes over a river. She is depicted in the figurehead holding the tail of Tam's horse. It's not a scalp.
Thanks so much for your insights and sharing your knowledge.
Considering the rise of piracy on the high seas a ramming bow might make a comeback.😂👍
😅😅
Super job and incredibly informing
Thank you Paulj
Glad you enjoyed it, Jim.
I'm not sure if I'm asking this correctly, but does bow shape determine whether or not a ship, specifically a yacht, can get an ice rating?
Bow shape would not much of be a factor for light ice, but to be a 'breaker', the vessel needs a bow that can ride up on the ice and then crush it with its weight.
it would be interesting to really see 2 vessels in heavy seas , a side by side comparison.
I've also wanted to see an old-fashioned tractor-pull between vessels.
@@ExpeditionYachts lol
MASHAALLAH khub valo video......
There is the length of the wave, the length of the ship, and the speed of the ship.
Isn't there an optimal speed where a ship goes the " most comfortable " way? Sure it may not be the fastest but still. Can such a speed be calculated easily or is it already known, just that i haven't heard of it?
Perhaps an expert can comment. My understanding is that there is something called 'hull speed' and a vessel does not want to go much over that speed, no matter how much horsepower you throw in it.
en.wikipedia.org/wiki/Hull_speed
hull speed for 60 m3ters is 18.8 knots
Wave making resistance depends dramatically on the general proportions and
shape of the hull: many modern displacement designs can easily exceed their
'hull speed' without planing.
sq root of water line in meters x 2.43 = hull speed in knots
Without planing huh? Neat! Got any good exemplars you could mention?
the vsv was wavepiercing in 1992. It all depends on the role. Turbinia 1886.
Wonderful content Paul! Question for you - isn’t that an ancient boat idea? That long sharp bow? I know on a smaller scale but - when you see these huge ships - it must be the same thinking. Right?!
Yes. If you scratch around on Google you'll see some amazing bows on ships-of-old, including bulbous bows, wave-piercing bows, etc.
Yes
I think the gold woman on the bow is holding out an olive branch!
What looks cool? Form follows function.
Obviously she’s holding an olive branch
awesome video and hilarious dad jokes
Hah, enjoyed the humour.
👍🏻
There is a big difference between big and smaller , also this ships remove water
And monitors ship....come back....
Not because it was not known before but because poor transition abilities for manufacturers and ingeneers. It is like to make new energy sources while people are scared bc of unknown and scared of faults. Not so strong position in life it is 😊
they're all wrong, soon you'll see the basketball bow design, it's going to beat them all.
What about a SWATH for stability
In theory- yes. I'm not sure why, but the Navy built SWATH prototypes and tested them, but there was no uptake.
Really I thought there were a few however I think a Russian billionaire has one and a few Oceangeography and science vessels
The Norwegian Ulstein X Bow is the one.
I agree.
I agree.
Great Video!!!!
Thanks!
I was aboard the, briefly pictured in the video , Steam Ship Delphine before it was restored, but it was still in fantastic shape. It is hard to see , and out of focus in the video, but behind the bridge cabin, is a large matching mahogany observation room, with big heavy roll down windows all around. All the built in bench seating, including the matching chairs around the central table, were upholstered in leopard skin. a theme that continued with good sized padded leopard skin insets on the walls, that separated the windows equidistantly as they went intirerly around the room, save for the entrance doors. the ship was used for a central command of all western navel planning in the Atlantic during WW2.
Down below is a triple expansion steam engine, all filigree engraved on almost every surface of the black metal used in the engine, trimmed in decorative brass, in the art deco streamline modern style, lots of curls on the decorative brass used on the corners and to frame some of the brass mechanical gear. like something out of a Jules Vernes movie set, except all functional , a very pretty effect. The mahogany paneled guest rooms were not huge, but the bathrooms were all done in small hexagonal white tile, in the now antique style of the day, save for the overhead. The floor tile continued up to form the bath tub, as it did along the walls and the sink support, I don't remember if the sink was also all tile , but it probably matched the bathtub . The deck sailors slept forward , in hammocks spread between the steel ribs of the bow, next to the un-insulated steel of the hull, and below the deck storage rooms.
Almost forgot, the davits pictured on top , here looking like they are for a white hulled lifeboat, were used for matching mahogany Chris craft power boats, with one tender open, and the other a cabin cruiser.
Thanks for these recollections! When I saw her in Portugal, they still had the matching tenders in the shed, and they were being offered with the vessel. However, I don'
t know if they are still onboard now.
I wonder how they got a hold of leapord skins for the restoration?
An acknowledgment: All the warships you showed were actually Pre-Dreadnoughts. Just wanted to point that out.
All of these new hulls are based on the following proposals of mine from 2003:
1- The Trimaran: The problem with a catamaran was that it couldn’t split large frontal waves into multiple angular, horizontal and vertical components to reduce the impact of the wave, so the central hull of a Trimaran could lead the other two hulls to split a large wave before it could hit the main hull.
The central hull also had to be placed well ahead of the lateral hulls to protect the lateral hulls from the wake generated by the central hull. This meant that the central hull, much like a spoon-shaped ice-breaker, could also climb on top of ice packs, pull the other two hulls over, and break the ice-pack with the weight of the vessel, not the force of the impact.
Three separate engines in the three hulls could also optimize steering to do away with the need for bow thrusters or azimuth pods. The shapes of the hull were convex wedges below and above the waterline, so that the convex wedge below the waterline had a pronounced and deep taper for it to spring back from plunges from high crests into deep troughs, whereas the convex top would break waves smashing on top into multiple angular components to reduce the vertical forces pushing the vessel down. The hull shape at bow, stern, and the sides was also convex, like semi-spherical wedges, to break bow, stern and beam waves into angular, horizontal, and vertical components to reduce the impact on the ship.
These would also break and deflect beam and stern waves.
Small ships could also have the tips of the lateral hulls designed as Anhedral wings, like those on the Harrier or C-17 aircraft, so, at slow speeds, these could serve as anchors to prevent the ship from tipping over to capsize, whereas at high speeds, these would generate lift and rise, just like aircraft, to have the lateral hulls hydrofoil at high speeds to reduce the drag.
You can think of this anhedral wing as an advanced iteration of the paravane and the drogue: www.mirtoart.com/image/I0000hgdYnQv9INU
The following ships were based on this concept of mine.
a- The Independence Class littoral vessel: en.wikipedia.org/wiki/Independence-class_littoral_combat_ship
b- The Adastra Trimaran: robbreport.com/motors/marine/custom-hi-tech-trimaran-yacht-adastra-hits-the-market-for-12-million-2857532/
2- Mono-hull Vessels with Convex Tops and Bottoms: These are different partial iterations of the wedged trimaran and spherical hulls for mono-hull vessels.
a- The Zumwalt Class destroyer is an exact mono-hull implementation of the Independence Class trimaran hull: www.usni.org/magazines/proceedings/2018/october/handling-zumwalt-class-destroyer
b- The Ulstein X-bow vessel is a spherical implementation of the convex top and bottom wedge hulls, with a very large free-board and a much shallower draft: www.boatdesign.net/threads/a-little-help-with-x-bow-ulstein.37365/
c- The Damen Sea-Axe is an angular implementation of the convex hull with a smaller freeboard and a deeper draft: www.superyachttimes.com/yacht-news/amels-sells-first-67m-sea-axe-fast-yacht-support-vessel
Vessels need to be able to spring back from deep troughs; for this, you need a long taper. This taper can be a shorter V-taper below the waterline or a much higher inverted-V taper above the waterline. The Axe-Bow uses the former, whereas the X-bow relies on the latter.
3- The Sharp-Keel, Rollover Vessel: A well-designed vessel can survive a wave-height 60% that of its length to prevent pitch-poling.
This design relied on a long-bow, which was essentialy a blade-like keel, to keep the boat steady, as it sliced or axed through the wave.
It had to be long enough for it to cross the wave and help haul the mid-ship across the wave before the boat pitch-poled.
The bow behind the blade-like keel, broadened, as a wedge, so it would spring back from dips into deep troughs.
The boat was kept long and flat to optimize the hull-speed, and so that beam waves could flow over the boat without capsizing it.
A partial trimaran was required to minimize capsizing and optimize hull efficiency. This isn’t very different from the Independence Class trimaran in concept, but is much smaller, so can rollover and self-right. A larger vessel would hurt the crew if it rolled over to self-right. Since this was a boat, not a ship, it could also roll-over and self-right.
The following boats are based on this concept:
a- The Thunder Child: www.bairdmaritime.com/work-boat-world/maritime-security-world/non-naval/thunder-child-ii-demonstrator-high-speed-patrol-boat-for-all-weather-conditions/
4- The Spherical or Oval Vessel: The most radical of my proposals was a spherical boat that could roll-over in the ocean, like a buoy or a ball, because a sphere would deflect the forces into different angular, horizontal and vertical components to reduce the force of impact of a wave. A sphere, because of the taper, would also rise back, like a spring, so remain buoyant. This design of mine had the inner structure like that of the gyroscope, connected to the outer hull with pivots, so the crew would remain horizontal even as the outer hull rolled over. The oval shape was a more practical iteration on the sphere for higher speeds. These also had rectangular cavities at the bottom and top, so the hull would work as a displacement hull at low speed and in stormy conditions, plane at higher speeds, and eventually hydrofoil at very high speeds.
The following vessels are based on this concept of mine.
a) The US Special Forces Ghost Vessel was based on an identical implementation of this concept of mine: interestingengineering.com/meet-the-ghost-the-boat-that-sails-through-bubbles
b)These SWATH catamaran vessels are also based on a partial implementation of the same concept. Since most of the turbulence is on the surface of the ocean, these slice through the turbulence with narrow multiple hulls and incorporate small water-planing surfaces(wings) at the maximum depth of the hull to resist capsizing forces: dmsonline.us/smooth-sailing-pros-and-cons-of-a-swath-vessel/
c) The Stiletto vessel, also based on a partial implementation of the concept, is a multi-hull vessel without the deep planning surfaces: en.wikipedia.org/wiki/M80_Stiletto
5- The Flared Bow: This has been the traditional design for centuries, and has nothing to do with me. When I designed the earlier hulls in 2003, I was just 35 years old. Now, I’m 54, and feel the age, so, for myself, I’d either opt for the Alucia, the MMM or Karima, the Sea Wolf or Ithasca, or the Norwegian patrol vessel, the Scottish fisheries patrol vessel, the US T-AGOS vessel, or an offshore support vessel converted into an expedition yacht. All of these have flared bows because I want something cheap, off the market, and economical. I’m also too old to bother with designing new hulls. I want my expedition yacht to be able to carry the Gweduck amphibious aircraft and, yet, be economical to operate, so I would choose the flared bow.
The Ithasca was sold in September, looks like you just missed out! Thanks for the links. Where can I find links to your research?
Héllo , ultimately there is no good or bad Bow I think it all depends on the shape and size of boat you want!? and also maybe a certain comfort in the wave, right?
It all depends on the sea condition you are operating in- and that changes in a blink of an eye. The captains who operate these different vessels have strong opinions based on experience.
⛲⛺♠🎥🎞📽🎬📺🪔🔐⚖🔬🏁🚩🎌🏴☠
X-Bow ships look like really big canoes.
They are really. And if you follow the progress on those designs you’ll see they’ve started offering a matching stern shape making them even more like a traditional canoe of north america
I've always loved the look and motion of the Coast Guard CUTTERS !!!
Can you do a vide on semi SWATH please.
One-day maybe. There really aren't many around- the military has probably done most of those builds as 'trials', and none of them really caught on, as far as I know. There may be some being built now for wind-farm maintenance.
Exactly Right Cousin Paul !!!! Here, here!! 👍👍✌👏😄 cheers Cuz!!!!!
Hello Peter! Glad to hear from you.
How important is “sexy” in a ship’s bow?
You saw the figure head from the Cutty Sark clutching the hair ..😉 If your Rich or Powerful or just want to intimidate the locals .. Viking Dragon heads. ..and there's another off shore bow... And as for the reverse bow look at ancient Greek Triremes..
So in a word Yes.😉
Very informative! Thank you!
Glad you enjoyed it!
From reading about the Xbow design. These were made for oil rig support vessels in the North Sea where the rear needed to be stable to transport large items in (rarely flat) high swell seas up to the oil rigs. They are now being used for offshore wind farms where you often have to service them especially in the winter where sea swells are the norm. Since many ferry ships have swing up bow doors as well to speed up boarding cars and trucks while others exit at the rear,. why don't we see more Xbow ferry ships considering their slow transit speeds and as on a schedule, the need to transit in bad weather where the slamming and rocking motion has an impact on passengers/cargo and the damage to the ship over time. Surely car carrying cargo ships would be an ideal Xbow customer. PLus it means the ship can transit faster and now slow down as much in bad sea states.
All true. The expedition cruise ships they have built report that they are extremely stable and sea-kindly for both crew and guests. But shipyards like to build what they know already, and they only adapt if the customers insist.
@@ExpeditionYachts Plus they don't look a stylish. I can see them selling on cruises into rough water - Alaska/Antarctica/Scandanavia/Japan or anywhere that passengers are not used to rough seas (indians?/Middle east?/Chinese?). If they can also cut fuel and emissions that might also drive adoption. Superyacht owners want to show off so its unlikely to gain much traction in the Med/Caribbean
Wonder if x-bow can be make to work in boats in 45-50 meters range. The go anywhere pocket explorer size. Haven't come across one built in that size and then again commercial boats that take that design doesn't necessarily come in those sizes either.
From what I read, the Sea-Axe might be better under 60 meters.
Hi Paul thanks again for the video. l sailed in the eighties on anchor handling supply vessels and also as towmaster on different trips and l also sail on a lot of sailing yachts l am a pensioner now but l think this new bow design is a big improvement not only for fuel consumption but also the slamming of the vessel will be a lot less so much more comfortable for the crew.
Ah yes- the crew. Owners and guests seldom make serious passages on motor yachts, and so it is the crew that endures bad seakeeping and excessive pitch and slamming. Unless you've been out there, you don't have a clue. Thanks for note.
@@ExpeditionYachts Was the sea and anchor helmsman on a Korean era us navy minesweeper. Yep been thru many a storm. no fun with green water over the bow.
This is great and all, but where are the vids of all of these X-bow and Axe-bow ships in extreme weather? One would think that a hull designed to cut through a wave rather than go over would be prone to "dive" into waves rather than slam into then rise over them.
Unless these ships are being built as partial submarines, I would think diving into the base of a 30+foot wave would put an extreme force on the hulls as they pushed deeper into the wave.
If you search around you’ll find video of the Ulstein’s out in severe weather. I haven’t found any of the Damen axe bow
@@ExpeditionYachts I was talking more on the notion of 40ft + waves, which I haven't seen a single ship of this design present in. I have seen a commenter on one of your other videos say they were the designer of the X-bow, and that it was great on very large ships in calm to choppy weather conditions, not storm force waves.