Deck / Hull Fastenings

[Old Forum]

Keith Dennis
   
Posted on Saturday, February 16, 2008 - 07:11 pm:      
Whilst refitting the restored rubbing strakes to Thurn Too, I found the starboard bow area of the hull was flexing. Further investigation showed that four of the the pop-rivets used to secure the deck to the hull had pulled through the deck leaving the two unconnected for some 3 or 4 feet. My boat has twice been badly hit by incompetent cruiser skippers on the Norfolk Broads. On neither occasion was I present but bystanders left me in no doubt that both strikes had been substantial. My guess is that the hull flexed and pulled the rivets through the deck. I have used quarter inch, one inch long brass set screws to reunite the deck and the hull. Any one else had this sort of problem?

[Old Forum]

Adrian Evans
Username: Adrian_evans

Registered: 03-2007
   
Posted on Tuesday, May 20, 2008 - 08:21 pm:      
Keith when I pranged Peggoty, it pulled several rivets out of each side at the prow. as part of my repair I fibreglassed the seam between deck and hull for the first couple of feet on each side, and I'm convinced this is now Stronger, more rigid than it was. if I needed to taKe the deck off in the future, I could easily zip the fibreglass open with a cutting disc in my angle grinder

[Old Forum]

Keith Dennis
Username: Keith_dennis

Registered: 04-2008
   
Posted on Saturday, June 14, 2008 - 09:49 pm:      
Thanks Adrian. If I meet the same problem again I'll follow your example.

[Old Forum]

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Friday, November 21, 2008 - 09:03 am:      
Hi Adrian. I am thinking of doing your deck seam treatment this winter. How much do you have to abraid the surfaces before applying the fibreglass and what tool do you use for this?

[Old Forum]

Adrian Evans
Username: Adrian_evans

Registered: 03-2007
   
Posted on Friday, November 21, 2008 - 03:48 pm:      
Hi Martin! nice to hear from you! I used a 4 1/2" angle grinder, which sounds drastic, but the idea is to cut through the resin and expose the existing glass at least here and there, so the new resin wets and bonds with the existing glass. It is quite difficult using the grinder in the confined space, and definitely needs googles and dust mask!

the working conditions meant that for me the abrading job wasn't too thorough, but the result is clearly stronger that it was. The fibreglass is fine cosmeticly on the inside. Don't be tempted to glass too large an area at once though - my repair all went fine, until I got cocky and tried to do a bigger piece, which wouldn't stay in place upside down, and the fumes from the resin became unbearable.
I would stick to pieces 6" by 18" or so maximum.

I used ratchet straps and blocks of wood to make sure the deck was tight down to the hull, but if you haven't got the repair to deal with that I did and leave the rivets in place, this obviously wont be an issue. I sealed from the outside by gunning puraflex (cheaper brand than Sikaflex!)into the seam.
Good luck!

Adrian

[Old Forum]

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Friday, November 21, 2008 - 04:14 pm:      
Thanks very much Adrian.Sounds rather a nasty job. Perhaps I'll wait until the Spring!

[Old Forum]

Geoffrey Osborn
Username: Geoffrey_osborn

Registered: 01-2009
   
Posted on Tuesday, January 13, 2009 - 09:24 pm:      
On Calidris (WB36) I noticed salt water inside around the port midships - after some heavy weather sailing. I found some of the hull/deck rivets had corroded. I believe salt water had penetrated the joint. I expect to remove the rubbing strake this Spring, and replace those rivets (and possibly others) with marine quality.
Has anyone else had this problem?

[Old Forum]

Martin_cartwright
Username: Martin_cartwright

Registered: 04-2008
   
Posted on Wednesday, January 14, 2009 - 06:26 pm:      
Hi Geoffrey. When I replaced the rubbing strakes last year I noticed that some of the rivets were a bit suspect (one or two had actually 'missed' altogether!). However, rather than drill out the suspect rivets, I merely replaced the mastic joint and enlarged the screws holding the rubbing strake (so that these clamp the hull and deck together as well). I have had no problems todate despite the heavy weather we had last year.