repairing a crack in the grid

[thomashoebus]

I have a crack in the grid of my boat (oceanis 440). I grinded out the crack and found out that the crack went halfway the depth of the polyester. In fact it was a piece of polyester (from the grid) 8 by 5 cm wich was delaminated which I cut away.. The underlying polyester matting is ok. I don't know if it is ok to leave it like that. I could fill it up with 3m 5200 but that won't give any extra structural strength. I could also start with polyester and fiberglas matting but then i have to open up my water tanks and grind a much bigger piece away.

And i clould leave it like that. The crack didn't go through the grid just halfway and just for 8 cm long , the grid is a lot bigger than that. Iobserved that the crack opened up 1-2 mm when the boat was put ashore that's wy i grinded it out. Perhaps the opening of the crack when put ashore was the reason wy it was cracked since this suggests a lot of stress at that point. I bought the boat 5 years ago and sailed with it like that since then. I observed the outside of the hul around the keel for signs of evenual grounding and can't find any cracks in the gelcoat around the keel. No lumps in front of or depressions behind the keel.

Has anyone some advice about what to do

 

[vyv_cox]

I suspect you know the answer already. The correct action to take is to repair it properly, with epoxy layup resin and chopped strand glass. Epoxy will give a better bond than polyester resin. If you consider that this is too extreme a repair for the extent of the defect, then don't do it but the risk assessment is up to you. Putting some filler in it will do nothing for the strength, as you say.

I think it will be very difficult for anybody here to give definitive advice. As your boat is made by such a major manufacturer I suggest you try to get them involved. It sounds like some sort of manufacturing defect and they just might be prepared to help with a repair. Contact the local Beneteau agent.

 

[savageseadog]

I'd have a word with the designer and Beneteau, Your insurance company might have something to say if they hear about it /forums/images/graemlins/frown.gif

 

[Talbot]

[ QUOTE ]
Perhaps the opening of the crack when put ashore was the reason wy it was cracked since this suggests a lot of stress at that point.

[/ QUOTE ]

Which obviously needs some beefing up to help take the load.

 

[srp]

You can't (or shouldn't) use chopped strand mat with epoxy. It is held together with a binder that is only soluble with with polyester resin, so if used with epoxy it doesn't wet out properly. Use something like biaxial glass cloth instead - it'll be much stronger.

 

[rickp]

I didn't think epoxy was the thing to use with chopped strand matting, because the lack of solvents in the epoxy don't break down the PVA holding the chopped strand matting together?

Edit: ahah - someone else thinks the same too /forums/images/graemlins/smile.gif

Rick

 

[vyv_cox]

Oops

I forgot about that little problem! The reason I suggested csm was that it's much easier for a novice to accommodate all the likely stresses by using this material. Using woven cloth requires that each layer be rotated to achieve the same thing. I bought a roll of woven stuff many years ago and it's still got plenty on it.