Hi Alex, fun videos as I've owned 3 Gemini's over the years and spen some time at the factory talking to Tony. The hose in the compression post is a necessary vent to allow the light weight ply centerboard to drop down. As you let the board down you're creating a vaccum of sorts that needs to be filled. the air from the vent does this quickly. Without the vent water has to rush up past the centerboard to fill the space left by the dropping centerboard and creates flow in the opposite direction of the dropping board working against you. since the line and crank only pull up the centerboard and the bolt only locks the centerboard at whatever level the board has dropped to, you have no way of pushing it down. Sorry, wish I had seen the video earlier. All my Gemini's had vents in the top of the centerboard cases.
Yes I did realise after I shot that clip. Will be putting it in a better location as bellow the compression post wasn’t a great idea when the box section didn’t have any load spreading surfaces. Good place to hide it though
Nice shout on the companion reference books. Just ordered the whole series. Like your content, TH-cam drown your videos in these really long ads that I can't cancel. But that's you tube.
@@crazyrayuk36 thanks for watching and I’m glad you like the books! I find them really helpful. TH-cam is terrible with ads and I always find it worse when you watch on a tv for some reason.
That was my only thought but ran with it this season and didn’t have a problem with it needing to vent luckily. Was really easy to raise and lower and I’m much happier knowing that I don’t have an extra hole in the boat!
I agree with the previous comments. Totally sealed up centerboard cases get pressure built ups. They can gurgle and make odd noises. They can even spray water out if the water finds opening. It will be interesting what you learn from this.
@@carlamerritt490 had no problems this season with it but I will be adding a vent but in a better place and I think I have finally found a good solution.
Clever idea that balloon!! I was watching and asking myself, "How is he going to get that flat though!!?" but then we see!. Alex this channel is fast becoming one of my favourite watches. Can't wait to see the boat on the water but until then I am quite enjoying the DIY.
The tube in your compression post would either eliminate all the gurgle of air trapped in keel box or more importantly, relieve the stress of buoyancy on the otherwise thin fiberglass box. The boat pounding and compressing air in that box could generate enough force to break something if not vented.
Well thought out solution to your problem, welded plate must help spread the load. I’ve seen people use G10 to take compression and avoid future rot, looking forward to the mast raising.
Excellent job. The compression post takes a huge strain when under sail. Sailing Fair Isle channel had to reset their mast after it had sunk and they used some special synthetic non compression material in the base.
great video , great explanation. will be interesting to see the gel coat spider crack videos you will be doing as my newest purchase has a few i need to do.....
I'm wondering if the hose was a conduit instead for electric to go to the mast, but there is no access at the deck, so that is quite baffling. If the hose was used to run any leaks out to the clear bottom of the hull, it would have been better to just eliminate the hose because the hose would cause any uncatched water to pool to the top of the hose.
It's possible it's original laminate. I recently did the p-bracket housing on my westerly and that had loads of dry laminate. could easily be the standard of laminating in the 80's.
Yeah air vent I think but annoying place for it and worked well without it this season. Just glad I got rid of an extra hole in the boat. Could add a better one back in if needed.
Thanks! Balloon came out really easy and the finish was better than I thought it would be. You can see it but it’s quite smooth and it’s hidden anyway and doesn’t need to look seem less.
if the vent is not there there is a chance for under- or overpressure in the box. one consequence is that the walls cave in or out and this mightweaken them over time. another one might be that at some point this pressure will find its way and create hissing noises in the best case and a path for water in the worst case. the vent is the way to prevent all this.
Yeah that makes sense. Ran it this season as I want to find a better solution for it. Didn’t have any wall flex or anything but it should have it for this one as I have found a solution.
You know I wonder if that hose inside of the mast support was a previous owner's attempt at creating a wire chase for running new masthead wiring after the mast replacement. They might have had trouble with the stock wiring and thought it easier to run new wires through the keel box instead of pulling down the headliner. After the install of their attempt at the wire chase, they had weakened the mast support base which caused the support compression that created the dip in the coach top.
I found out it was a vent hose but as I found out this season, there was no problem not having one. Just glad I don’t have an extra hole in the boat under something under high load!
Alex pretty sure the through hull was a vent for the keel box not sure what it will do not having probably slap and splash and you might find the centreboard rattles a bit more without the damping effect of water in the box, but as you previously pointed out the centre board winch system can leak so water should fill the keel box and without a vent it will just trap air and maybe cavitate
Yeah I think it was! Ran with it this season and didn’t have any issues which is good! Very annoying place for a vent and I’m glad I have one less hole in the boat. Really easy to raise and lower and you can kind of see what’s happening in the box through the window at top which is nice too!
In a big sea the CB case may come out of the water, fill with air then as the boat slams back down the water pressure will compress the trapped air that has nowhere to go. It will go for the weakest point and could blow a hole in the case. It needs that vent.
Yes serious structural repairs like that MUST be done in Epoxy. Polyester or even Vinyl Ester just don't have the permanent adhesive strength for that job.
Not finished watching but i would recommend G10 or similar on the top. Pound for pound stronger than steel. Only problem diamond's are cheaper. Keep up the good work
you dont really need a mast support in a deck stepped mast, a transversal beam all the way under deck and both sides of the hull will do the load spreading for the weight of the mast and it will keep the area clearer too
That would be cool to do but would be a big modification too. This post also supports the side to side on the centreboard casing a little too so plenty to consider.
Yes it is,@@AlexGoesSailing For next year you could consider a dagger board slipped port side like in the corsairs and this will be used as mast load spreading too ;-p
Definitely an air vent but also had no effect without it so just glad I don’t have the extra hole in a silly place.
10 หลายเดือนก่อน +1
it's called a compression post... it's supposed to compress... or was that the crumble zone...? well it's crumbling as well... so either way, it's fine, I guess?
Hi Alex, fun videos as I've owned 3 Gemini's over the years and spen some time at the factory talking to Tony. The hose in the compression post is a necessary vent to allow the light weight ply centerboard to drop down. As you let the board down you're creating a vaccum of sorts that needs to be filled. the air from the vent does this quickly. Without the vent water has to rush up past the centerboard to fill the space left by the dropping centerboard and creates flow in the opposite direction of the dropping board working against you. since the line and crank only pull up the centerboard and the bolt only locks the centerboard at whatever level the board has dropped to, you have no way of pushing it down. Sorry, wish I had seen the video earlier. All my Gemini's had vents in the top of the centerboard cases.
Yes I did realise after I shot that clip. Will be putting it in a better location as bellow the compression post wasn’t a great idea when the box section didn’t have any load spreading surfaces. Good place to hide it though
Nice shout on the companion reference books. Just ordered the whole series. Like your content, TH-cam drown your videos in these really long ads that I can't cancel. But that's you tube.
@@crazyrayuk36 thanks for watching and I’m glad you like the books! I find them really helpful. TH-cam is terrible with ads and I always find it worse when you watch on a tv for some reason.
hi Alex, I think that hose is to vent the centreboard case.
That was my only thought but ran with it this season and didn’t have a problem with it needing to vent luckily. Was really easy to raise and lower and I’m much happier knowing that I don’t have an extra hole in the boat!
I agree with the previous comments. Totally sealed up centerboard cases get pressure built ups. They can gurgle and make odd noises. They can even spray water out if the water finds opening. It will be interesting what you learn from this.
@@carlamerritt490 had no problems this season with it but I will be adding a vent but in a better place and I think I have finally found a good solution.
31:28 -> There you got the -2º :D
Great vid - love it
Cheers!
Clever idea that balloon!! I was watching and asking myself, "How is he going to get that flat though!!?" but then we see!. Alex this channel is fast becoming one of my favourite watches. Can't wait to see the boat on the water but until then I am quite enjoying the DIY.
Thanks Dave I really appreciate it! I have no idea how I came up with that balloon idea 😂
Hi Alex. I also believe the hose is a vent for the centreboard housing. Great video’s keep them coming.
Yeah I think so too. Thanks for watching and plenty more to come!
good job proper repair and will make a difference
Thank you!!!
The tube in your compression post would either eliminate all the gurgle of air trapped in keel box or more importantly, relieve the stress of buoyancy on the otherwise thin fiberglass box. The boat pounding and compressing air in that box could generate enough force to break something if not vented.
Yeah one will be going back in but in a better place for sure!
Well thought out solution to your problem, welded plate must help spread the load. I’ve seen people use G10 to take compression and avoid future rot, looking forward to the mast raising.
Yeah g10 would be very nice! Mast raising will be out this week!
Excellent job. The compression post takes a huge strain when under sail. Sailing Fair Isle channel had to reset their mast after it had sunk and they used some special synthetic non compression material in the base.
Yeah I recently watched them too! Quite the repair job!
Good job Alex, looks great
Thanks!!!
Nice one Alex, sorted…. Andy UK
Thanks Andy!
Great Job!
Cheers!
Really interesting episode! 😎
Thank you!
Take care that is a breather pipe for the dagger board casing when water enters the casing so the air presser escapes. From Clive in SW France
It will be getting a vent but in a better place!
great video , great explanation. will be interesting to see the gel coat spider crack videos you will be doing as my newest purchase has a few i need to do.....
Thank you! From my research the gelcoat stuff shouldn’t be too bad.
The channel Refit and Sail has an episode of gellcoating the topsides of a contessa 32 very useful
That would be very handy!!!
I'm wondering if the hose was a conduit instead for electric to go to the mast, but there is no access at the deck, so that is quite baffling. If the hose was used to run any leaks out to the clear bottom of the hull, it would have been better to just eliminate the hose because the hose would cause any uncatched water to pool to the top of the hose.
Found out it was ment for a vent but as I discovered this season I didn’t need it as all worked well. Just one less hole in the boat!
Nice job. Those oscillating tools are brilliant.
Thank you! They definitely are!
Best diy vid
Thank you!
Alex, suggestion: don’t use plywood but use a piece of G10 solid GRP.
That would be really nice! Quite hard to come across unfortunately so coated with epoxy and used marine ply!
It's possible it's original laminate. I recently did the p-bracket housing on my westerly and that had loads of dry laminate. could easily be the standard of laminating in the 80's.
Possibly but this boat was built in the 2000’s 😬
Nice video and good job 👌 Greetings, Felix
Thank you Felix!
I think its most likely an air vent to allow the case to fully flood. Also could be used for flushing mud etc out of the case?
Yeah air vent I think but annoying place for it and worked well without it this season. Just glad I got rid of an extra hole in the boat. Could add a better one back in if needed.
A stonking repair job, bombproof now! Did the balloon come out OK and how was the finish in the centreboard case?
Thanks! Balloon came out really easy and the finish was better than I thought it would be. You can see it but it’s quite smooth and it’s hidden anyway and doesn’t need to look seem less.
if the vent is not there there is a chance for under- or overpressure in the box. one consequence is that the walls cave in or out and this mightweaken them over time. another one might be that at some point this pressure will find its way and create hissing noises in the best case and a path for water in the worst case. the vent is the way to prevent all this.
Yeah that makes sense. Ran it this season as I want to find a better solution for it. Didn’t have any wall flex or anything but it should have it for this one as I have found a solution.
The vent was added for what Marcus was saying but more to prevent leaks at the raising hardware from the pressure. @@AlexGoesSailing
You make a mould ?
Nope! The balloon helped a lot!
Great work :) and good epoxy skills, love your videos
Thank you!
Another thought, could the hose be there to stop water hammer in the centre case in rough seas?
Interesting thought! I had it in some rough stuff and didn’t see anything out of place or hear anything.
You know I wonder if that hose inside of the mast support was a previous owner's attempt at creating a wire chase for running new masthead wiring after the mast replacement. They might have had trouble with the stock wiring and thought it easier to run new wires through the keel box instead of pulling down the headliner. After the install of their attempt at the wire chase, they had weakened the mast support base which caused the support compression that created the dip in the coach top.
I found out it was a vent hose but as I found out this season, there was no problem not having one. Just glad I don’t have an extra hole in the boat under something under high load!
Alex pretty sure the through hull was a vent for the keel box not sure what it will do not having probably slap and splash and you might find the centreboard rattles a bit more without the damping effect of water in the box, but as you previously pointed out the centre board winch system can leak so water should fill the keel box and without a vent it will just trap air and maybe cavitate
Yeah I think it was! Ran with it this season and didn’t have any issues which is good! Very annoying place for a vent and I’m glad I have one less hole in the boat. Really easy to raise and lower and you can kind of see what’s happening in the box through the window at top which is nice too!
@@AlexGoesSailing how far back in time are we?
@@arch1etatts511 this was 10ish months ago! Did lots of sailing so couldn’t edit as much but I’m catching up quickly!
@@AlexGoesSailing Looking forward to it!
Air burp from the keel box?
Yeah it’s an air vent in a silly place so will be putting one in a better place!
In a big sea the CB case may come out of the water, fill with air then as the boat slams back down the water pressure will compress the trapped air that has nowhere to go. It will go for the weakest point and could blow a hole in the case. It needs that vent.
It will be getting a vent but just in a better place!
Cool video
Cheers!
Yes serious structural repairs like that MUST be done in Epoxy. Polyester or even Vinyl Ester just don't have the permanent adhesive strength for that job.
Exactly my thoughts!
I hope u left a vent there I would just put 10mm vent tube in
Not yet but considering the best option because what it had wasn’t it! Worked fine this season but will be good to have one.
Not finished watching but i would recommend G10 or similar on the top. Pound for pound stronger than steel. Only problem diamond's are cheaper. Keep up the good work
Yeah I agree! Also quite hard to find too. Thanks for watching!
@AlexGoesSailing I picked some 5mm A4 sheets on ebay, and doubled them up
@@grahamm2015 oh nice!
well that was unexpected 🤷♂ Let water out of the mast. 🤣🤣
You are improving the boat and making it a lot safer, but it was a bit of a random setup.
Very strange indeed!
Might that be someone's attempt to run a board raising line back to the cockpit?
Just an air vent after I did some research. Will be getting one again but just in a different place!
Don’t you just love uncovering some previous owners bodges! The joys of old boats. You did good there.
It’s always an interesting experience 😂 thank you!
Another 5 minute, 3 day boat job!😅
😂
you dont really need a mast support in a deck stepped mast, a transversal beam all the way under deck and both sides of the hull will do the load spreading for the weight of the mast and it will keep the area clearer too
That would be cool to do but would be a big modification too. This post also supports the side to side on the centreboard casing a little too so plenty to consider.
Yes it is,@@AlexGoesSailing For next year you could consider a dagger board slipped port side like in the corsairs and this will be used as mast load spreading too ;-p
@@ammartinezguzman I will check that out!
Sounds like a different way of making a mast support.
I'd love to know more about that hose fitting and why, curious. I've read the thoughts below.
Definitely an air vent but also had no effect without it so just glad I don’t have the extra hole in a silly place.
it's called a compression post... it's supposed to compress... or was that the crumble zone...? well it's crumbling as well... so either way, it's fine, I guess?
The post didn’t compress luckily! The centreboard wasn’t supposed to either but the force they must have applied in transport but have been a lot!
Its called a compression post because it counters compression forces. It's not supposed to compress.