FOUND A MAJOR STRUCTURAL PROBLEM ON MY NEW TRIMARAN | Ep.125 

hi Alex, I think that hose is to vent the centreboard case.

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.

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.

Hi Alex. I also believe the hose is a vent for the centreboard housing. Great video’s keep them coming.

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.

31:28 -> There you got the -2º :D Great vid - love it

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.

Alex, suggestion: don’t use plywood but use a piece of G10 solid GRP.

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

Nice one Alex, sorted…. Andy UK

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.

good job proper repair and will make a difference

Good job Alex, looks great

The channel Refit and Sail has an episode of gellcoating the topsides of a contessa 32 very useful

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.....

Really interesting episode! 😎

Nice job. Those oscillating tools are brilliant.

Great Job!

Nice video and good job 👌 Greetings, Felix

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.

Best diy vid

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.

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?

Great work :) and good epoxy skills, love your videos

A stonking repair job, bombproof now! Did the balloon come out OK and how was the finish in the centreboard case?

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.

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.

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.

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

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

Don’t you just love uncovering some previous owners bodges! The joys of old boats. You did good there.

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.

Cool video

You make a mould ?

Another thought, could the hose be there to stop water hammer in the centre case in rough seas?

I hope u left a vent there I would just put 10mm vent tube in

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

Might that be someone's attempt to run a board raising line back to the cockpit?

Air burp from the keel box?

I'd love to know more about that hose fitting and why, curious. I've read the thoughts below.

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?