Jump to content

rotten deck repair. advice please

Recommended Posts

I discovered an area of the bow deck that appears to be softer than the surrounding area and am wondering what the best practise would be for a repair.

Im assuming that this area is glassed over marine ply though Im not 100% sure (1981 Compass H28) Does anybody have any ideas on what may lie beneath the glass?


My 1st question is this:

Should I attempt a repair by lifting the deck covering, opening up the deck GELCOAT + fibreglass and repair from the top OR should I avoid damaging the gelcoat on the deck and repair from beneath (which I presume would take a bit of thought to excecute.) /


Im not 100% in favour of disturbing the deck covering as I would not be able to duplicate the finish. Repairing from below might be difficult but can be concealed when complete.

It appears that the glass fibre beneath the fault might be at least 3mm-4mm thick as it withstands the pressure from above when somebody applies downward pressure however. it moves in & out when pushed by hand on that soft spot only. The area outside that spot is rock solid.



What type of repair would you advise?

Im aware the typical rotten plywood repair would be to remove all rotten material, then cut a new piece of marine ply to fit and glass over a couple of layers.


Since I might be repairing from below, what would be a suitable repair method?


It would be difficult to support a piece of marine ply from below get it to set.Could I....Instead of using a new piece of plywood... would a thick paste of powdered resin to fill the gap (which might stick better than plywood), then covered with layers of fibre cloth smothered in resin after be just as structurally secure.?


your ideas please. Ive tried to include some pics to show the area but this site does not allow pics greater than 500kb and I dont know how to compress the images to make it smaller. :problem:



finally got a solution to resize pics for upload.I used a wet cloth to wet/mark the soft area.above deck.

marked area of faulty soft spot - Copy-400.jpg

area on deck where soft spot exists-400.jpg

area imediately beneath deck where fault exists-400.jpg

approximate thickness of deck taken from anchor hold looking towards faulty area 2-400.jpg

faulty area uncovered from below-400.jpg

Link to post
Share on other sites

the glass " Harry's" had balsa core foredeck and cabin tops also cockpit floor and seats, the rest is solid glass, may pay to drill a few random 1/8" holes into the core from underneath to see how wet it all is and do the tap test with a small hammer, repair from underneath which for a foredeck isn't that bad unless the anchor well is the culprit, plenty of grunt in the outer skin so it'll keep shape without sagging etc

Link to post
Share on other sites

Ok. so go in from underneath it is then. :thumbup: Thanks for your thoughts on this.


Next question:

if the original decking is glassed balsa core, would it make any difference if I use marine ply instead?. The area between top & bottom deck glass seems to be at least 8-10mm thick.

Was marine ply available in 1980?


Got some good ideas here on this link: Dripping resin will be my biggest concern...


http://www.cruisersforum.com/forums/f55 ... 00333.html

a little trick when upside down glassing is to cut your cloth to size,lay it on a piece of oven paper and wet it out.


wet out the surface to be glassed.


roll up your wetted out cloth in the oven paper then take it to the repair and with a roller start glassing the cloth to the underside un rolling as you go.

once it is up there,peel off the paper,and repeat with more layers.


if using epoxy thickening the mix slightly with collodial silica helps as well.


So I need to plan this well as I can only work on it on the mooring and /or alongside a wharf on good weather days which is going to be scarce soon with winter coming.

still trying to minimise the size of the pics to upload.... :x



What causes perspex to "craze"?. Can it be repaired ie. the craze remove to make it clear again or should crazed perspex just be replaced?
Link to post
Share on other sites
What causes perspex to "craze"?. Can it be repaired ie. the craze remove to make it clear again or should crazed perspex just be replaced?

No sadly it is a replace job.

bugger :(

dont mind replacing them but its the time factor removing, working whilst on mooring, then taking it away for new ones to be cut, then returned to the boat, fitted....and hoping for a good day to do it in. :thumbdown:


Any ideas wheels on what weather proof material to use to cover the window openings of the H28 after I remove all the perspex windows to have a new set cut in case it rains & I am unable to return while weather is foul. :think: best I remove all at once to save the 8 return trips if I have to do it per window.

:think: :idea: On second thought, the windows are of the same size port & starboard, so may only need to remove and cover one side and have 2 of each new window cut.

Link to post
Share on other sites

pretty sure there are window edge outer moulds/ surrounds floating around for H28's, contact the association (friendly bunch that don't bite) as they're pretty helpful and you may be able to size the windows from the surrounds or someone may have patterns already made

Link to post
Share on other sites

bugger :(

dont mind replacing them but its the time factor removing, working whilst on mooring,


Any ideas wheels on what weather proof material to use to cover the window openings .

Yeah it is a bit. It's the UV that does it. Although it doesn't seem to lessen the strength any, or by much if there is some loss. It seems to occur around the 10yr mark for hatches and for any side ports, a little longer. I have seen someone try sanding the perspex back to remove the crazing, but that was as far as they goit and then they chucked the hatches. So I have no clue if they could have re-polished the perspex or not. As they found, it was a much bigger job than they expected.

I just had all my hatches out and I used 3M 100mph tape and plastic sheet and tapped up all the hatches. Worked a treat for the first few rain storms. I think I stretched the use by date a little too far though and they eventually let go and dumped a heap of water inside the boat. :(

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...