Cracks in bilge

[Quirocat]

Hile cleaning out my bilge to rewire and replumb ny 1995 sunbeam 44 i found these cracks in the mold. There are two just aft of the keel and two just forward of the mast compression pole.

Wondering if this is strucural damage or cosmetic?

Help, advice?

Tobias

[Jimbo485]

Start grinding!

If the cracks disappear before you reach FG, you are fine.

If they continue, start to worry.

No answers here until you grind....

[boatpoker]

Originally Posted by Jimbo485

Start grinding!

If the cracks disappear before you reach FG, you are fine.

If they continue, start to worry.

No answers here until you grind....

[chrisjs]

If you do not have any water intrusion, it is very hard to think these are anything but cosmetic. You have the maximum hull intrusion pressure in the bilge, given just how easily water gets into a boat, it is hard to see how these could possibly penetrate the hull. I assume there are no deformations or cracks visible from the outside??

[djmarchand]

It does look ominous. Those look like classic cracks where the stress on the hull overloaded the tensile strength of the fiberglass on the upper surfaces. These wouldn't necessarily penetrate to the bottom surfaces until they got worse.

OTOH I would have thought that the static stress in those areas puts compression on the top and tension on the bottom and wouldn't lead to that kind of crack. Maybe it was caused by a really hard grounding.

As others have said, grind them out. You might try a test place that is easy to access and patch if you find that the cracks are only through the surface. If they go deep, then call in a professional.

David

[minaret]

Not very good pics, but looks like its delaminated stringer tabbing to me. Is that a limber hole in a stringer which someone has run some wires through? If so, it's almost certainly stringer delam related to a grounding or similar.

[Oceanride007]

Is this the Sunbeam 44 that was for sale in Thailand till recent? Did you have it surveyed.

[onestepcsy37]

I had similar cracks on an older boat some years ago, but I had actual drops of water slowly coming through! I picked it up out of the water and added a couple of layers of glass over it. No further problems. The crack was at a stressed bend in the hull.

Sent from my GT-P3113 using Cruisers Sailing Forum mobile app

[barnakiel]

I would inspect this thoroughly. Looks like damage from grounding or else the boat lightly built and sat on her keel in the boatyard.

Not a thing to disregard or pretend it is not there.

b.

[Quirocat]

Thank you all for the advice. I am talking with the boatyard re construction tecniques and possible answers. The boat is a typically robust nordic build, very solid. They say it was probably due to a grounding. Nothing came up on the survey except the starboard settee cracking on the inner mold with a bad repair attempt. On outhaul, the keel and hull were impecable. This boat was bought in florida from the original owners whom cruised her lightly from build date of 95. One atlantic crossing and 15 years in the carribean. The cracks where the cables are seen are around a cable pass between the salon through the bulkhead into the forward cabin.
I don't mind grinding, it's removing all of the water tanks that is daunting.

[David_Old_Jersey]

Maybe start with a bit of test grinding (with a dremel?) to see how deep the crack goes. and keep yer fingers crossed!

[Dale Hedtke]

Are the cracks "new"? If they've always been there, they could be shrinkage cracks when the polyester resin was curing. This often happens in confined spaces (that don't allow sufficient cooling-the cure is an exothermic reaction that produces heat.)

Is there a layer of built up resin/filler in that area, such as to level out the bilge? It looks like that. Do the cracks run in a specific direction (indicative of stress cracking) or are they random (indicative of shrinkage cracks.)

I agree that doing some grinding is required to better undertand the extent of the problem. It could be a serious structural issue.

[Steve W]

Is it possible the cracks are in poured epoxy/resin? My Newport 28 has poured epoxy encapsulating the keel bolts and forming a very small, shallow bilge area for the bilge pump, something Newport thought was a good idea (no idea why). The epoxy had a hairline crack in it since I bought it in 1999. Surveyor said this is common and not an issue. No leaks, no evidence of corrosion it has never grown and it is a 1986 model. I like the idea of test grinding an area with a Dremel.

[Quirocat]

So, the previous owners confessed that they had a soft grounding and then got pounded by waves before getting her afloat. The boatyard then advised them that it was not a structural issue, so they left it unrepaired and continued to sail her for over ten years with no problem. The surveyor completely missed it and was very cavalier about having done so. No big deal?
Stringer delam due to a grounding seems to be the winner. I will pull out the 7 water tanks and grind and glass like the devil.

Thanks everyone for your help. What a wealth of experience!

[Quirocat]

Actually, according to the boatyard, so say the previous owners, this is not stringer delam. It is some kind of filler desgned as a shock absorber in case of grounding. They advised then that it was no big deal. I'm still talking to the boatyard as to how best to proceed. I won't rest well until the cracks are repaired.