Thanks. It was a daunting job at least. Having very little fibreglass experience, and knowing that a mistake is going to be very costly. Can’t wait to try it out now. And I’ll have a lot of new things to learn no doubt
Very eye opening video you've made here, I enjoy watching every single detail of it. What is that putty you used to compensate the unlevel top deck, i.e., link to purchase?
Hi, thanks for watching. The link is here www.bunnings.com.au/selleys-50g-knead-it-aqua-epoxy-putty_p1230080?region_id=118161&gclid=CjwKCAjw9-6oBhBaEiwAHv1QvBFrqTg6rXwMRYp2Sy0OrEDGqEVaOPUEqfvQKH1W9RPoFw3SGBIoZBoCbaEQAvD_BwE&gclsrc=aw.ds
Nice video very helpful I’m ordering a sail for my mirage 580 as well, what did you use to attach the side stays the the boat couldn’t find it in you parts list
I would make both the fore & aft stays adjustable so that in high wind, you can get rake the mast back as far as possible, reducing the effective height of the centre of pressure above the deck. In lighter air, you want the centre of pressure as high as possible, to catch more wind strength (the wind velocity is vertically stratified, slowest at the water surface and increasing with height). Raking the mast forward a little will raise the the centre of sail area higher, but there is an optimum you would have to experiment with. You can make a model of your sail with a sheet of cardboard, find the balance point which is the centre of area. When the sail is raked to have the centre of area directly above the mast step, that will will be close to catching maximum wind force for off the wind sailing (see crab claw rigs). It is only when sailing upwind that you want maximum sail height with a vertical mast to minimise span load & induced drag to enable sailing as close to the wind as possible. You may find it useful to include a attach the sheet to be boom with a length of chock chord as this will allow the sail to feather off and spill excessive gust force, making it more comfortable to retain stability in harsh conditions, particularly found in off shore summer winds. You just want enough to add some reactivity to the rig, not so much that you loose efficiency.
Hi Ken, thank you for your comment. I see what you're saying. I am very much a novice sailor so I am re-reading to fully get my head around your message, but I am extremely keen to gain more knowledge. The rear stay is adjustable but not from the cockpit which is what you would ideally want to achieve what you're saying yeah? There is a small amount of shock cord on the sheet rope so would that have the same effect as what you describe with spilling excessive gust force?
@@Beyondthebackyard-au Hi, I reconsidered my reply & thought I'd take a different approach with it. I just haven't had time to redo it yet. I had dinghy sailing experience at a state & national level when I was younger & just sailed for fun in later years. Started slalom kayaking about 1972 or so but that too became recreational. I still kayak &, have an old Sea Wasp now, but have not added a sail to it yet. I'll try to redo the reply in a way that I hope will be clearer.
@@Beyondthebackyard-au This is my 2nd go at this reply. I have looked at the video again & agree that the existing shock chord appears to fulfil this function. However, I suspect it may be prone trigger either too early or late to maintain sailing efficiency. Why not try it a while & see how it goes before considering altering anything. That’s what I would do. Anyway way, I have rewritten my comment as it may be of some interest. Just remember that sailing is about making small speed gains that add up over time to larger distance advantages in racing. Tactical gains & losses can sometimes be huge by comparison. You may not wish to mess with this sail trim thing & that’s fine too. To understand sailing rigs, we need some context, so I’ll cover some basic things you probably already know but other readers may not. A sail generates pressure across both of its surface. The local reaction force is approximately 90 degrees to the sail surface. The surface is curved to maintain smooth airflow over both surfaces, so the total reaction force is the sum of these local force vectors. The sail being angled across the boat, angles the reaction force across the boat & somewhat forward. When sailing upwind (about 40-45 degrees to the true wind direction), the reaction force has a small forward component and large sideways component. Sail boats have a centre board, lee board or deep keel to counter the sideways force, minimising sideways drift (leeway). Efficient sail boats may sail as high as 40 degrees to the true wind, but that is just not going to happen for a sailing kayak, especially one without a lee board. As the boat turns away from the wind, & the sail is eases, the whole reaction force rotated forward, proportionally increasing the forward vector while reducing the sideways vector. However, the total reaction force is approximately proportional to square of the relative flow velocity across the sail (not the true wind speed). The relative flow velocity is a factor of the boats speed and direction as well as the wind speed itself. Sail boats tend to be fastest across the wind or a little down and across wind. Sailing directly downwind is relatively slow as the windspeed relative to the sail is reduced & with the wind square on to the sail, pressure is lost on the lee surface of the sail due to detached flow. It is important to maintain smooth attached flow on the lee (low pressure) side of the sail if at all possible. It's just not possible when saining dead down wind (DDW) When sailing upwind or across the wind, the sideways reaction vector, being somewhat above the hull & the hull & board resisting that force, creates a force couple or moment that tends to tip the boat over. This tipping moment can be countered by the hull’s stability, fixed or dynamic ballast. Dynamic ballast would be the crew hiking out. The further the crew can hike out, the more tipping force can be resisted before capsize & the stronger wind the boat can be sailed before capsize. The maximum wind the boat can withstand before capsize in called the design wind. Generally, the higher the design wind, the faster the boats maximum potential speed (other design characteristics being equal). So, what happens above design wind? Well, we can reduce the sail’s reaction force or bring the centre of pressure of that force lower down towards the hull, reducing the it’s tipping leverage. Generally, both of these are done together. Gust reactive rigs are a fairly modern 20th century invention. Prior to that, rigs were rigid and sails were depowered by reefing, changing to smaller sails and adjusting sail twist manually. The problem is that takes time and has to be done before there is a problem. Consequently, these adjustments were made for the maximum gust force that might be experienced, which might account for less than 5% of the time. The other 95% of the time, the rig was well below maximum efficiency. Reactive rigs rely on the material flex & sail design to depower the sail but only in strong gusts above design wind. The reaction is much faster than any human is capable of & switched on and off at a specific wind force that is determined by rig tensions. So, if we are going to try to emulate this kind of thing on a kayak sail that has not been designed in this way, we need to bear in mind that the system needs to be triggered at a specific wind force and not gradually implement before that wind force is reached. Basically, the mechanism under consideration here, is allowing the sail to feather and twist at the same time, reducing its overall angle to the wind (feathering) but in a way that the peak feathers more than the foot (twist). This can be achieved simply by easing the main sheet which will allows the Clew (lower rear corner of the sail) to rise and fall away to lee at the same time. This needs to be a fast automatic response, faster than a human. My suggestion is to use a length of shock chord from the main sheet block & through the deck fitting or another block attached to the deck fitting & then to a cleat on the deck. This allows the shock chord to be tensioned to match your design wind threshold. You would have to experiment with the tension. When the threshold is reached, the shock chord will stretch, allowing the main sheet block to lift off the deck and release some sheet to ease and twist the sail. I would have expected that 15 cm of shock cord would be sufficient (it's a guess). Obviously, the existing cord is longer than that, so I suspect it’s not designed to trigger at a specific wind but rather give a wider ranging response, which may mean the sheet is not held fast until design wind is experienced. If that is the case, the sheet setting can not be held optimal while the wind speed is varying below the design wind. Therefore, the sheet setting can never be ideal. In sail boat racing, we watch the sail & make adjustments constantly try to keep the sail at optimum performance as much as we are able. Small gains over time, it becomes a habitual sailing paradigm but it makes the difference between those who get lapped and those who are in contention. In other words, paying attention might just get you to a safe haven before a squall breaks. Oh, I should add that if the shock cord allows the head of the sail to twist off too far, the sail camber can invert at the peak, causing a lot of drag. we don't want that happening, & for that reason may want to limit then length of the shock cord. Now I have made a guess as to it's length, but it's only a guess. These things are in practice determined by trial and error testing on the boat in real conditions. Now a little tip about sailing off the wind. in a gust, ease sheet and steer more down wind. This will give you more time at higher speeds in the gust, with less heeling moment while hopefully surfing across the swells. When the gust has passed, tighten up the sheet and head more upwind. This tends to increase apparent wind speed over the sail as long as it's not over done, giving the boat good drive force & bringing you up to the next gust sooner than a straight course would have done. While this zig zag course is further, your extra speed and time in gusts will get you to your destination faster overall.
Thanks Ken, A lot of that makes sense but I think I will have to read over once or twice more to get it to sink in. And perhaps I need to buy myself a sailing dinghy to really accelerate my learning (I have often toyed with the idea of buying one) as the kayak sail I kind of feel like it's not real sailing.
Sorry for the late reply. No none needed. Obviously though this means you're not traveling up wind. Even a beam reach is a bit of a stretch, not a lot of assistance.
@Johosephat Copp Yes they are , I just got 2 sea dog sails from Richard for my friend and I. Great video @Beyond the Backyard this was really helpful :)
Yeah I’ve seen it done both with and without. Me, I don’t enough money to take the risk not doing it lol. Plus I’d hate to be out at sea to find a leak. Better safe than sorry :)
@@Beyondthebackyard-au Good point and that makes sense. Does the Sea Dog sail give you a quality boost. Oh and you purchased all the hardware right yourself, no hardware came with the sail. Good job.
@@joethi4981 yes, I had to buy all the deck hardware myself. The sail came with the deck mounting plate and the side and rear stays as well as the sheet rope and uphaul rope. But everything as far as screws and deck hardware I had to buy. There should be a list in the description, if not they will send you the list when you purchase it.
Looks like a lot of work went into it. You did a great job
Thanks. It was a daunting job at least. Having very little fibreglass experience, and knowing that a mistake is going to be very costly. Can’t wait to try it out now. And I’ll have a lot of new things to learn no doubt
Good job. I want to see a video of it in action.
Very eye opening video you've made here, I enjoy watching every single detail of it. What is that putty you used to compensate the unlevel top deck, i.e., link to purchase?
Hi, thanks for watching. The link is here www.bunnings.com.au/selleys-50g-knead-it-aqua-epoxy-putty_p1230080?region_id=118161&gclid=CjwKCAjw9-6oBhBaEiwAHv1QvBFrqTg6rXwMRYp2Sy0OrEDGqEVaOPUEqfvQKH1W9RPoFw3SGBIoZBoCbaEQAvD_BwE&gclsrc=aw.ds
Nice video very helpful I’m ordering a sail for my mirage 580 as well, what did you use to attach the side stays the the boat couldn’t find it in you parts list
I used what I call deck line guides. I can find an eBay link later if you like.
Thanks I found them on eBay
I would make both the fore & aft stays adjustable so that in high wind, you can get rake the mast back as far as possible, reducing the effective height of the centre of pressure above the deck. In lighter air, you want the centre of pressure as high as possible, to catch more wind strength (the wind velocity is vertically stratified, slowest at the water surface and increasing with height). Raking the mast forward a little will raise the the centre of sail area higher, but there is an optimum you would have to experiment with. You can make a model of your sail with a sheet of cardboard, find the balance point which is the centre of area. When the sail is raked to have the centre of area directly above the mast step, that will will be close to catching maximum wind force for off the wind sailing (see crab claw rigs). It is only when sailing upwind that you want maximum sail height with a vertical mast to minimise span load & induced drag to enable sailing as close to the wind as possible. You may find it useful to include a attach the sheet to be boom with a length of chock chord as this will allow the sail to feather off and spill excessive gust force, making it more comfortable to retain stability in harsh conditions, particularly found in off shore summer winds. You just want enough to add some reactivity to the rig, not so much that you loose efficiency.
Hi Ken, thank you for your comment. I see what you're saying. I am very much a novice sailor so I am re-reading to fully get my head around your message, but I am extremely keen to gain more knowledge. The rear stay is adjustable but not from the cockpit which is what you would ideally want to achieve what you're saying yeah? There is a small amount of shock cord on the sheet rope so would that have the same effect as what you describe with spilling excessive gust force?
Read your last reply but it seems to be gone now as I go to reply to it. You sound like a wealth of knowledge on sailing, thanks for the pointers.
@@Beyondthebackyard-au Hi, I reconsidered my reply & thought I'd take a different approach with it. I just haven't had time to redo it yet. I had dinghy sailing experience at a state & national level when I was younger & just sailed for fun in later years. Started slalom kayaking about 1972 or so but that too became recreational. I still kayak &, have an old Sea Wasp now, but have not added a sail to it yet. I'll try to redo the reply in a way that I hope will be clearer.
@@Beyondthebackyard-au This is my 2nd go at this reply.
I have looked at the video again & agree that the existing shock chord appears to fulfil this function. However, I suspect it may be prone trigger either too early or late to maintain sailing efficiency. Why not try it a while & see how it goes before considering altering anything. That’s what I would do. Anyway way, I have rewritten my comment as it may be of some interest. Just remember that sailing is about making small speed gains that add up over time to larger distance advantages in racing. Tactical gains & losses can sometimes be huge by comparison. You may not wish to mess with this sail trim thing & that’s fine too.
To understand sailing rigs, we need some context, so I’ll cover some basic things you probably already know but other readers may not. A sail generates pressure across both of its surface. The local reaction force is approximately 90 degrees to the sail surface. The surface is curved to maintain smooth airflow over both surfaces, so the total reaction force is the sum of these local force vectors. The sail being angled across the boat, angles the reaction force across the boat & somewhat forward. When sailing upwind (about 40-45 degrees to the true wind direction), the reaction force has a small forward component and large sideways component. Sail boats have a centre board, lee board or deep keel to counter the sideways force, minimising sideways drift (leeway). Efficient sail boats may sail as high as 40 degrees to the true wind, but that is just not going to happen for a sailing kayak, especially one without a lee board.
As the boat turns away from the wind, & the sail is eases, the whole reaction force rotated forward, proportionally increasing the forward vector while reducing the sideways vector. However, the total reaction force is approximately proportional to square of the relative flow velocity across the sail (not the true wind speed). The relative flow velocity is a factor of the boats speed and direction as well as the wind speed itself. Sail boats tend to be fastest across the wind or a little down and across wind. Sailing directly downwind is relatively slow as the windspeed relative to the sail is reduced & with the wind square on to the sail, pressure is lost on the lee surface of the sail due to detached flow. It is important to maintain smooth attached flow on the lee (low pressure) side of the sail if at all possible. It's just not possible when saining dead down wind (DDW)
When sailing upwind or across the wind, the sideways reaction vector, being somewhat above the hull & the hull & board resisting that force, creates a force couple or moment that tends to tip the boat over. This tipping moment can be countered by the hull’s stability, fixed or dynamic ballast. Dynamic ballast would be the crew hiking out. The further the crew can hike out, the more tipping force can be resisted before capsize & the stronger wind the boat can be sailed before capsize. The maximum wind the boat can withstand before capsize in called the design wind. Generally, the higher the design wind, the faster the boats maximum potential speed (other design characteristics being equal).
So, what happens above design wind? Well, we can reduce the sail’s reaction force or bring the centre of pressure of that force lower down towards the hull, reducing the it’s tipping leverage. Generally, both of these are done together.
Gust reactive rigs are a fairly modern 20th century invention. Prior to that, rigs were rigid and sails were depowered by reefing, changing to smaller sails and adjusting sail twist manually. The problem is that takes time and has to be done before there is a problem. Consequently, these adjustments were made for the maximum gust force that might be experienced, which might account for less than 5% of the time. The other 95% of the time, the rig was well below maximum efficiency.
Reactive rigs rely on the material flex & sail design to depower the sail but only in strong gusts above design wind. The reaction is much faster than any human is capable of & switched on and off at a specific wind force that is determined by rig tensions.
So, if we are going to try to emulate this kind of thing on a kayak sail that has not been designed in this way, we need to bear in mind that the system needs to be triggered at a specific wind force and not gradually implement before that wind force is reached. Basically, the mechanism under consideration here, is allowing the sail to feather and twist at the same time, reducing its overall angle to the wind (feathering) but in a way that the peak feathers more than the foot (twist). This can be achieved simply by easing the main sheet which will allows the Clew (lower rear corner of the sail) to rise and fall away to lee at the same time. This needs to be a fast automatic response, faster than a human.
My suggestion is to use a length of shock chord from the main sheet block & through the deck fitting or another block attached to the deck fitting & then to a cleat on the deck. This allows the shock chord to be tensioned to match your design wind threshold. You would have to experiment with the tension. When the threshold is reached, the shock chord will stretch, allowing the main sheet block to lift off the deck and release some sheet to ease and twist the sail. I would have expected that 15 cm of shock cord would be sufficient (it's a guess). Obviously, the existing cord is longer than that, so I suspect it’s not designed to trigger at a specific wind but rather give a wider ranging response, which may mean the sheet is not held fast until design wind is experienced. If that is the case, the sheet setting can not be held optimal while the wind speed is varying below the design wind. Therefore, the sheet setting can never be ideal. In sail boat racing, we watch the sail & make adjustments constantly try to keep the sail at optimum performance as much as we are able. Small gains over time, it becomes a habitual sailing paradigm but it makes the difference between those who get lapped and those who are in contention. In other words, paying attention might just get you to a safe haven before a squall breaks.
Oh, I should add that if the shock cord allows the head of the sail to twist off too far, the sail camber can invert at the peak, causing a lot of drag. we don't want that happening, & for that reason may want to limit then length of the shock cord. Now I have made a guess as to it's length, but it's only a guess. These things are in practice determined by trial and error testing on the boat in real conditions.
Now a little tip about sailing off the wind. in a gust, ease sheet and steer more down wind. This will give you more time at higher speeds in the gust, with less heeling moment while hopefully surfing across the swells. When the gust has passed, tighten up the sheet and head more upwind. This tends to increase apparent wind speed over the sail as long as it's not over done, giving the boat good drive force & bringing you up to the next gust sooner than a straight course would have done. While this zig zag course is further, your extra speed and time in gusts will get you to your destination faster overall.
Thanks Ken, A lot of that makes sense but I think I will have to read over once or twice more to get it to sink in. And perhaps I need to buy myself a sailing dinghy to really accelerate my learning (I have often toyed with the idea of buying one) as the kayak sail I kind of feel like it's not real sailing.
Nice work. Looks good.
Thanks. Much appreciated
Great video!
Thank you, I hope it has helped
This video is so amazing!! Love it!!
Thank you so much!!
Cool! No type of centerboard?
Sorry for the late reply. No none needed. Obviously though this means you're not traveling up wind. Even a beam reach is a bit of a stretch, not a lot of assistance.
Is SeaDog still in business? my email was rejected?
Yes, they should be. Did you use seadogsails1@gmail.com? I’ll message him and find out if that’s the one that bounced.
@Johosephat Copp Yes they are , I just got 2 sea dog sails from Richard for my friend and I. Great video @Beyond the Backyard this was really helpful :)
It is a good idea to reinforce the deck, and you did a good job, but honestly, I don't think it is really necessary.
Yeah I’ve seen it done both with and without. Me, I don’t enough money to take the risk not doing it lol. Plus I’d hate to be out at sea to find a leak. Better safe than sorry :)
@@Beyondthebackyard-au Good point and that makes sense. Does the Sea Dog sail give you a quality boost. Oh and you purchased all the hardware right yourself, no hardware came with the sail. Good job.
@@joethi4981 yes, I had to buy all the deck hardware myself. The sail came with the deck mounting plate and the side and rear stays as well as the sheet rope and uphaul rope. But everything as far as screws and deck hardware I had to buy. There should be a list in the description, if not they will send you the list when you purchase it.
@@Beyondthebackyard-au Thanks again and I really appreciate your attention to detail.
👍🍺
Thanks mate