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back of hull transoms bulging between gudgeons
http://www.hobie.com/au/en/forums/viewtopic.php?f=14&t=56572		 Page 1 of 1
Author:  Josefk [ Fri Dec 11, 2015 6:06 am ]
Post subject:  back of hull transoms bulging between gudgeons
About 6 months ago I noticed the gap between the rudder pin and transom on the port side hull was closing. At first I thought the gudgeons had been pushed in - perhaps by reversing the rudders into coral or beach but now after watching it closely over the last 6 months it seems as if the actual hull rear is swelling or bulging out somehow and now is contacting the rudder pin making steering tough. The rudder pin lines up perfectly well between the gudgeons and hole through the gunwale just now when I assemble the rudders the lower casing rubs against the hull there. I have some pictures below that may make more sense. I have seen mention of an aluminum plate the gudgeon screws attach to corroding - could this be the problem. The port hull is worst, the outer glass has now cracked and in fact some sort of beige substance (looked like filler) was around the area today. Any ideas? Am I looking at rebuilding the transoms?


Here is the port hull transom closeup. You can see the beige gunk on top of gudgeon which seems to be coming from the hull.

Image

A look at the transom side on.

Image

This is the same hull from the other side

Image

and finally, the starboard hull transom. this is also starting to bulge as the port hull looked 6 months ago.

Image

Your collective insight and wisdom is always appreciated!

Josef
Author:  John Lunn [ Fri Dec 11, 2015 8:57 am ]
Post subject:  Re: back of hull transoms bulging between gudgeons
After a good sail, is there water in your hulls?
How do you drain the hulls after sailing?

Do you leave your drain plugs in when you park the H16?
As you probably know, this is not a good idea, as the hulls have to 'breathe'.

It is possible that the water came in through the gudgeon screw-holes
OR
through the drain-plug housing (should be removed every year or two, fresh silicone applied and replaced).

I'd wait for others to comment, however my suspicions are that you've got some long term damage to the sterns.
The transom is built up from a sandwich of an aluminum plate and plywood, underneath the fibreglass.
Looks to me like there has been a build up of water which is causing the plywood to swell and delaminate.

This can be repaired, although it will not be simple.

Hulls should always be kept as dry as possible, and vented.
Author:  srm [ Fri Dec 11, 2015 9:11 am ]
Post subject:  Re: back of hull transoms bulging between gudgeons
I agree with the above. It looks like long term exposure to moisture has caused the plywood to swell (and probably rot too). I suspect you're going to be doing some glass work on the transom. Probably best to cut an access port into the aft deck and get a light in there and see what's going on. Definitely doesn't look good though.

sm
Author:  mdgann [ Fri Dec 11, 2015 2:00 pm ]
Post subject:  Re: back of hull transoms bulging between gudgeons
Can you say DE-LAM-IN-ATION. Yep, water, stress and time. Who says plastics don't corrode.
Author:  MBounds [ Sat Dec 12, 2015 10:52 am ]
Post subject:  Re: back of hull transoms bulging between gudgeons
John Lunn wrote:
Looks to me like there has been a build up of water which is causing the plywood to swell and delaminate.

Bingo.

I see much fiberglass work in your future. Or a new (to you) boat. (That one has been ridden hard and put away wet a few too many times.)
Author:  jim-doty [ Sun Dec 13, 2015 6:33 am ]
Post subject:  Re: back of hull transoms bulging between gudgeons
My H-17 did this. The swelling is caused by the wet plywood rotting. I was able to fix mine by cutting out the wet wood, letting it dry, then putting in a piece of marine plywood and glassing it back up.
Author:  Josefk [ Sun Dec 13, 2015 7:09 am ]
Post subject:  Re: back of hull transoms bulging between gudgeons
Thanks everyone,

I greatly appreciate the input and combined wisdom. This forum is a great resource especially when I'm about the only Hobie guy on this island. The boat is from the early 80s and it was in a sorry state when I got it 4 years ago. Lots of delam in the decks, holes in hull sides from typhoon damage after it was blown from its trailer and smashed up a bit. I did a fair bit of work on it just to get it back in the water and it has given me 4 great years.

After each sail it was drained (by leaning back on the beach wheels) then parked flat covered with tarp on beach with out drain plugs. I did a keel job last summer and that stopped most water intake. For future reference should I have been doing it differently? Perhaps parking it with bows slightly raised?

I wouldn't have spent the time restoring it if there was the chance of getting newer or better hulls where I am (a rock in the pacific) In the same spirit I'll have at it and see what I can do - if I get another summer out of it it'll be time well spent. Resin and glass is cheap and there's nothing more fun than messing around with ole boats. I found a couple of references on similar jobs which have given me an idea on what to expect. posted here in case it helps anyone else down the line.

viewtopic.php?f=45&t=35893

http://s1319.photobucket.com/user/jsaut ... t=2&page=1

viewtopic.php?f=14&t=43099&p=180001&hilit=transom+fix#p180001

So my plan of action is to cut holes for ports to be able to access the area. Take out the damaged ply/aluminum plate and rebuild. Is the construction of the transom (outside to in) glass>alum plate>ply>glass? I'll know soon enough I suppose but if anyone has more detailed info let me know.

thanks
Author:  jackB [ Sun Dec 13, 2015 5:00 pm ]
Post subject:  Re: back of hull transoms bulging between gudgeons
Josefk wrote:
So my plan of action is to cut holes for ports to be able to access the area.


Make sure to cut a hole, do your repair, and then install the ports. This will give you an extra inch space to work with.
Author:  jim-doty [ Mon Dec 14, 2015 6:18 am ]
Post subject:  Re: back of hull transoms bulging between gudgeons
My 17 was (from outside to inside) glass, plywood, aluminum plate, glass. I think my plywood got wet from leaking gudgeon holes since the worst of the the swelling was right there. I was able to fix one side without cutting a porthole. You could try working just from the outside and then cutting the porthole if you need to.
Author:  abbman [ Mon Dec 14, 2015 9:46 am ]
Post subject:  Re: back of hull transoms bulging between gudgeons
So far the transom repair I did is holding up. You referenced my photobucket pics. I glued the plate in with thickened epoxy. I used 1708 biaxial cloth layers to cover the plate. I then chopped mat to fill small gaps and thickened epoxy to fill in the rest. I ordered all the materials from US Composites.

James
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