Flexible deck

Post Reply
Lively22
Posts: 7
Joined: Wed Jul 09, 2014 8:30 pm
Anti Spam measure: Yes
AntiSpam Text: Westerly

Flexible deck

Post by Lively22 »

Hi all

My 1969 cirrus has a flexible foredeck, the owner of a marina that she is currently in told me that the core in the fiberglass laminate had rotted away and would need replacing a very expensive job. I'm not so sure as a friends cirrus also has a flex in the foredeck.
Is this something no should worry about look into? When I drilled through the cabin bulkhead to fit a depth sounder I didn't find any balsa...

Thanks
User avatar
Nigel Birch
Posts: 679
Joined: Wed Apr 25, 2007 11:42 am
Anti Spam measure: No
AntiSpam Text: Westerly
Location: Exeter "Willow" in Topsham, Devon

Re: Flexible deck

Post by Nigel Birch »

I think I would drill an exploratory hole in the centre of the flexible bit and see what comes out. I don't think it's necessarily an expensive job if you do it yourself. Get yourself a copy of Don Casey's book (http://www.amazon.com/Sailboat-Hull-Dec ... 0070133697) if repairs are necessary....
Nigel
Konsort "Willow" K200 Topsham
Lively22
Posts: 7
Joined: Wed Jul 09, 2014 8:30 pm
Anti Spam measure: Yes
AntiSpam Text: Westerly

Re: Flexible deck

Post by Lively22 »

Thanks for that I did have a look, one half of the foredeck is lovely fresh (40yr old) wood the other half is a gooey mess of the constituent parts of what was once wood... Thanks to a badly fitted deck vent...no sealant of any kind, now trying to decide how much fiberglass to remove and if the mast needs to come down again.
User avatar
rhumlady
Posts: 678
Joined: Tue Feb 21, 2006 9:26 pm
Anti Spam measure: No
AntiSpam Text: westerly
Location: Clyde area

Re: Flexible deck

Post by rhumlady »

Tap with your knuckle around the area you think has the problem to get a rough idea of the area to be treated then use your drill to go through the underside of the deck to find the actual boundary. You know what you see when you hit the good stuff so the messy bit is removing the glass layer which you should be able to clean up and reuse once you have removed the grotty balsa. The biggest headache is sticking it all back up and not getting it all down your arms and in you hair and eyes. Having said that you need to grind the edge of the hole so as to get a good joint and that is messy no matter what you do to try and contain it.
Derek
Konsort 'Rhumlady' KT213
Jolly Roger
Posts: 1005
Joined: Mon Sep 02, 2013 1:08 pm
Anti Spam measure: No
AntiSpam Text: Westerly
Location: Kent, UK

Re: Flexible deck

Post by Jolly Roger »

If when you cut the fiberglass away and find some rot close to the edge of the cut, do not panic. You should be able to dig it out with a screwdriver or chisel and then pack the are with an epoxy filler.

When cutting the fiberglass, try and do it in one large section as you will find it easier to then refit neatly ready to fill and prepare for painting.
Roger
Concerto Fulmar FR38
Photos at http://s1294.photobucket.com/user/Conce ... 2/library/
Lively22
Posts: 7
Joined: Wed Jul 09, 2014 8:30 pm
Anti Spam measure: Yes
AntiSpam Text: Westerly

Re: Flexible deck

Post by Lively22 »

That all sounds like sound advice, thank you all. It's looking like half of the foredeck needs a nice lump of ply, got a feeling I'm opening a can of worms here....
Should I not worry about the mast being up as there is no real structural integrity anyway?
User avatar
rhumlady
Posts: 678
Joined: Tue Feb 21, 2006 9:26 pm
Anti Spam measure: No
AntiSpam Text: westerly
Location: Clyde area

Re: Flexible deck

Post by rhumlady »

I don't know the Cirrus so can't comment directly but on larger boats such as the Konsort the mast step is seperate and includes a plywood plate above a compression post to the deck. If this is not the case on the Cirrus and it is just sitting other balsa sandwich then yes you could well have a problem with the mast and it would probably be better down than up. Roger Ball has done the foredeck replacement on his Centaur and has detailed it on his blog. I don't have the link to hand but a Google search on 'a gentleman's yacht' should get you a mine of information on repaired to our boats or should that be rebuilding our boats.
Derek
Konsort 'Rhumlady' KT213
Jolly Roger
Posts: 1005
Joined: Mon Sep 02, 2013 1:08 pm
Anti Spam measure: No
AntiSpam Text: Westerly
Location: Kent, UK

Re: Flexible deck

Post by Jolly Roger »

A quick comment. Balsa sandwich would never have been under any load area, so there will be a plywood pad to spread the load. So you should be able to do the work without removing the mast.

Most repairs to rotten cored sandwich decks involve the deck layer being carefully cut out as one piece. Then all the old balsa core is removed and replaced with a fresh core material (can be balsa or foam) that is bonded to the lower skin. Then the deck section is bonded to the new core and all the cut edges are ground back on about a 10 to 1 slope and re-fiberglassed to create a strong join. This fiberglass is then ground to just below the finished deck level and coated with a gel coat to stop water penetration. This is sanded smooth and polished where it can be seen, otherwise just paint on top.

There was an article in Practical Boat Owner about 6 to 9 months ago of the repair of a small motor boat foredeck undergoing this process with lots of photographs. I might still have the magazine, if so I will advise which issue and if necessary scan the article for you.
Roger
Concerto Fulmar FR38
Photos at http://s1294.photobucket.com/user/Conce ... 2/library/
Post Reply