Rebedding or repair of deck block

Neicy · #1 04-10-2006

Hi all, Fairly new boat owner and a 28yr plus boat. While sailing a week ago a deck mounted block located on the gunnel area of the cockpit that guides the genoa line before wrapping the winch lifted and pulled loose from the deck. The deck in this area is solid glass (no core), however, the force bent the ss screws over at right angles and tore 2 of the holes in the glass pretty good. The block has been removed by cutting the screws and I am trying to decide how to proceed. The glass underneath the block in crazed but the main problem is the "large hole" from the pull up. Does this area need to be reglassed by a professional or would martex, 5200, or 4200 do the job? I have already removed the block on the other side to prevent the same thing in the future. On this side all I did was clean it really well, lightly sand, added 4200 to the surface, and as a strenghened factor bolted a piece of white marine plastic on the underside. Would this same approach work for the side in bad shape? It is not level at this time, I am just not sure of the best way. Thanks for input.

duffer1960 · #2 04-10-2006

You should use a stainless steel backing plate underneath, not plastic.

Neicy · #3 04-10-2006

Actually what I used was 1/2 inch Marine Lumber ( high-density) polyethylene that I purchased at West Marine and I put it on the underside not on deck top. However I get the picture. But the question is what about the side that pulled up. What constitutes glass repair vs filling with 5200 and redrilling. I can see the fibers as the gelcoat is missing all around one of the holes. This is the question. The 5200 I can probably handle, but the other I'll have to check in at the boatyard. UGH!!

Faster · #4 04-10-2006

This block actually will have twice the load of the jib sheet if it turns the sheet nearly 180 degrees and heads to the winch, so must be very securely anchored.

A quick and dirty job would be to level the deck side as best you can, fill the holes with long-stranded fiberglass filler (available at hardware stores), re-drill and reinstall the block with oversized SS backing plates (at least 3/16" thick - 1/4" better) The backing plate should be supported by the undamaged area of the underdeck.

Probably better: grind out the damage (as much from below as possible), and re-lay it up with roving and matte from below to minimize damage to the deck finish. Then redrill and reinstall using proper backing plates and good bedding compound.

Lucky it didn't come free and nail someone on deck!! (Been there)

Cheers
Ron

Neicy · #5 04-10-2006

Ron, Thanks for the info. You mention leveling the deck, but the block was factory attached to a raised circle just like the raised area the winches are on. The winches have a block of wood glassed over top and bottom per the Dufour owners manuel. This raised area the block was attached to is just glass and had no additional support but has lasted almost 30 years. I cannot level it with the deck, as it a raised circle the size of the goiot block. I attempted to leather mallet it slightly but could not tell if it would be the proper way to work it so I stopped. I had read some articles about drilling out and filling and them redrilling but this really does not look like that kind of job. I do not think I could fool with the fiberglass myself.

Faster · #6 04-10-2006

Hi Neicy
Do you have good access to the underside of the raised pad the block sat on? From the cockpit perhaps? Presumably there will be a raised hollow there. A backing plate shaped to fit and predrilled for the block bolt pattern could be slipped in place from below. Bed this plate in some fiberglass putty and reattach the block (or a new one) with longer bolts.

You can probably sand/grind the damaged area of the raised circle flush for the reinstall without too much trouble - wear a dust mask in any event.

Working with glass is not difficult, especially when you are not too concerned about the finish when you're done. I would think you would not have trouble getting advice (and assistance perhaps) from any DIY oriented boater you may know nearby.

In the meantime if the lead angle to the winch is reasonable from the rail or the track (should be 5-10 deg or so below horizontal) you could sail without using the damaged block, leading the sheets direct to the winch.

Good Luck
Ron

sailnaway · #7 04-10-2006

It is not clear if you have screws or was the block bolted all the way through the glass. It should be all the way through as someone here already pointed out. It should have flat washers 10-24 machine screws or 1/4-20 machine screws lock washers or nylock nuts and a backing plate would be even better. Bed both sides the block and the backing plate. If the thing was screwed in or bolted you can buy, fiber fill 3M high density filler. First wash the holes out with ACETONE and vac the dust out. If you have a dremel under cut each hole < > this will hold the filler in use masking tape on the underside wash again with ACETONE this makes sure it is moisture free dry is good. Martex is not white and is a little off colored. also Martex is not structural so don't use it where real strength is needed. After the 3M High density filler is cured you can apply gel coat Clearcoat makes good gel coat it only comes in quarts and stores for about 4-6 months after opening maybe less. If the block was screwed in with pointed screws then this is the way you should do it. Re drill and bed the filler will be as strong as the old glass. I had several times while building boats over the years when a crew put shaft struts in the wrong place or even drilled the through hulls wrong using staggered layers of cloth and resin over a hole on the inside with filler in the hole and painted with gel coat outside and wet sanded and buffed you would never know that hole was ever in the hull. I get to see some of the boats from time to time and I never saw one problem with doing it this way.

Neicy · #8 04-11-2006

Sailnaway,
Thanks for your information. It definately sounds like the way I should proceed. The block was through bolted with long screws, washers and nuts. The long screws on the back side pulled out and bent at 45, with the washers and nuts still attached. That is where the damage to the glass occurred. I cut the screws to be able to remove the block. I can get to the underneath via the quarter berth but will have to cut away some glass to be able to easily access the area for a backplate. The existing hole is only about the size of the bottom of a regular drinking glass. Also I can only see 2 of the holes as there is an overlap of glass for some reason. The other side was more easily accessed from the cockpit locker and I have already rebedded it and added the backplate.
If you have anything else helpful to add, please do as I plan to tackle this the weekend. Thanks!!

Petar · #9 05-17-2006

Neicy,

I will check my Dufour over the weekend and see what can be done. Do you have two winches on each side or only one? I have two and I guess when using those blocks you need to use the forward ones (if fitted) for better lead and less of strain on the line and the block. Suggestions for repair by other guys seem very practical. Last weekend i spent rewiring and relocating my instruments (finally). This long weekend I will go sailing for four days.

regards

Petar