Delamination Eeeek

[tgpt21]

I was washing down the other day when I noticed that there was a bulge on the deck in way of the starboard lower shroud chain-plate. PANIC. I stripped down the deck-head and inspected the fitting. I found that there was a chain-plate fitting bolted on to the bulkhead between the fore-cabin and the saloon but this was connected to only one of the two bolts on the through deck fitting. The other hade merely a nut, not even a washer only a nut.

I think what has been happening is that over the last 25 years the concentrated load on the bolt has caused the deck to flex and there has been delamination of the upper GRP from the plywood core.

I have made a repair by making up another chain-plate and bolting it to the bulkhead. But the delamination is going to be a problem. I have tried to inject epoxy through a series of holes but it appears to be a failure. Has anybody had success with this method? If so what is it I am doing wrong is it hole size. Am I too timid with my 3mm?

Also, I know that there will be a problem with dampness but I have some super duper adhesive used in the oil industry which will work even underwater! When I come to use this I want to get it right.

 

[Deleted member 36384]

What is the boat as that could lead to a better answer?

If you have a problem with dampness then you need to address that first. It is likely that the deck GRP layer which has separated from the core (you say it is plywood) has moisture underneath it now. Unless that is dry a repair will be futile and if it is rotting it needs to be replaced. One the repair has been made to the core and deck, check the top of the bulkhead for water ingress. It may be rotting from the inside of the ply if water has got to the edge of the ply (top of the bulkhead, for example). Reinstate the chain plates as design but with all the nuts and washers this time!

The manual below has instructions for dealing with failed bonding (note that delaminating is usually the layers of individual glass fibre matting separating), you probably have de-bonding. Refer to all of Section 5, "Repairing Core Related Damage" of this manual: -

http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf

Section 5 talks about injection hole size, drying methods, injection methods. It is very important to dry the area, "super duper adhesive" which works underwater is not the answer here.

Note that this manual is from West and they refer to their epoxy products but the techniques are applicable to other manufacturers products too. I just find the manual useful and refer to it often.

Consider the services of a surveyor if it's economically worth it.

 

[davidpbo]

I have been there and posted about it in these threads below:

http://www.ybw.com/forums/showthread.php?316619-Deck-Shroud-Fixing-Fibreglass-repair&highlight=Book%20on%20fibreglass%20repair

http://www.ybw.com/forums/showthread.php?319114-Cutting-Fibreglass-Goscut&highlight=Goscut

 

[sailorman]

What is the boat as that could lead to a better answer?

If you have a problem with dampness then you need to address that first. It is likely that the deck GRP layer which has separated from the core (you say it is plywood) has moisture underneath it now. Unless that is dry a repair will be futile and if it is rotting it needs to be replaced. One the repair has been made to the core and deck, check the top of the bulkhead for water ingress. It may be rotting from the inside of the ply if water has got to the edge of the ply (top of the bulkhead, for example). Reinstate the chain plates as design but with all the nuts and washers this time!

The manual below has instructions for dealing with failed bonding (note that delaminating is usually the layers of individual glass fibre matting separating), you probably have de-bonding. Refer to all of Section 5, "Repairing Core Related Damage" of this manual: -

http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf

Section 5 talks about injection hole size, drying methods, injection methods. It is very important to dry the area, "super duper adhesive" which works underwater is not the answer here.

Note that this manual is from West and they refer to their epoxy products but the techniques are applicable to other manufacturers products too. I just find the manual useful and refer to it often.

Consider the services of a surveyor if it's economically worth it.

extra_3:Gib Sea 372

 

[TQA]

CharlieCobra faced with a similar problem used pull on grease gun nipples screwed onto the underside and a grease gun loaded with wet set epoxy.

But to do a ' proper job ' you have to remove the top skin.

 

[davidpbo]

CharlieCobra faced with a similar problem used pull on grease gun nipples screwed onto the underside and a grease gun loaded with wet set epoxy.

But to do a ' proper job ' you have to remove the top skin.

Or the bottom skin if accessible and the top not cracked. A bit more difficult to repair from underneath but not impossible given it is probably a relatively small area.