Spider cracks

[margav]

I am considering making an offer for a 1988 Beneteau First 305. I would like to ask your advice on the following. The deck has spider cracks around shrouds and hatches. There are no soft spots. Does this threaten structural integrity. Would you recommend immediate repairs?
Many thanks!

[perchance]

For the most part these are probably gelcoat cracks and are generally more aesthetic rather than structural but a good survey will rule out structural issues.

[Suijin]

No and no, with an added dose of "it depends".

It's not at all unusual to find spider cracks in the gel coat around high stress points on a boat from this Vintage. My Valiant has them on the cockpit seats right below the primary winches. It is simply cosmetic and is a result of the gel coat being less flexible than the glass underneath. That said, you should examine the area to determine the source of the stress (such as the cleat) and check the seating of the fixture and it's backing plate/nuts if you can.

If the crazing is not symmetrical on both sides of the boat then there is always the possibility that it is the result of an impact on the topsides, such as from a collision. Check the topsides directly below the cracking for signs of repairs.

The only way to repair it is to fair it all down and recoat it, or paint it, which is needless to say a lot of work. Since it's cosmetic you can simply leave it but if the cracks widen or chips start to come out you would want to correct it at that point.

[Igotnuthin]

Often if you grind away the gelcoat, you'll find white lines in the glass..... DAMAGED. If it were MY boat, I would repair them right away..... but then, I repair boats. Everyone says,"it's just gelcoat cracks". If you leave them, you will eventually be able to feel the cracks "pucker" ....water getting in....water+glass= no good!

[David_Old_Jersey]

Those spider cracks don't seem to be specific to any fittings, and indeed also go along the bulwark / toerail - if all the decks are like that pic it would suggest to me that the entire deck has been flexing a tad (and if so also the hull - whilst all boats flex to some degree, nonetheless some flex a bit more than intended). Could be still simply cosmetic, but sooner or later it won't be. A grind and fill will solve the cosmetics and reveal whether they extend into the glass......whether fixing any underlying problem makes sense is another matter, for both costs reasons and avoiding creating new stress points.

Boat now 25 years old - I suspect builder and designer were thinking primarily about performance and cost, not so much about longevity. But 2 out of 3 really ain't bad.

Would be of interest to know whether her sister ships are the same (not to say that is a good thing!), but could mean that this one has simply led a harder than average life. or had heavier than average owners!

One thing is for sure, if it was cheap and easy to fix the Vendor would have done it pre-sale!

I would buy on price (and likely leave as is).......just not as an heirloom! (or for going RTW for a couple of years).

[barnakiel]

Bendy. Laminate flexed and gelco cracked. Shrouds: deck lifted by the element anchoring shrouds down below. Hatches: are just openings in the panel and that's where you see most cracks (esp close to corners).

b.

[GordMay]

See also ➥ http://www.cruisersforum.com/forums/...ction-619.html

And ➥ http://www.cruisersforum.com/forums/...t-1-a-944.html

[margav]

Our next step is to get a survey! Thanks for all the input, this is very helpful!

[hd002e]

Is there any way to test (without a professional survey) if the structural integrity has been compromised?

[minaret]

Originally Posted by Igotnuthin

Often if you grind away the gelcoat, you'll find white lines in the glass..... DAMAGED. If it were MY boat, I would repair them right away..... but then, I repair boats. Everyone says,"it's just gelcoat cracks". If you leave them, you will eventually be able to feel the cracks "pucker" ....water getting in....water+glass= no good!

You are clearly a pro. I'd say at least 90% of the "cosmetic" cracks I grind out are actually glass fractures. The spider web shape is a dead giveaway, cosmetic gelcoat cracks generally don't spiderweb. Cracks like this can only be permanently fixed by grinding them out and glassing them, not just by filling over them. I've mentioned this here many times to much disbelief. Nice to see a fellow pro on the forum!

[David_Old_Jersey]

Originally Posted by hd002e

Is there any way to test (without a professional survey) if the structural integrity has been compromised?

Bounce up and down on the decks - if available, bring a fat mate!.......and look at the Vendors face!

[David_Old_Jersey]

Originally Posted by Igotnuthin

Everyone says,"it's just gelcoat cracks".

Probably because it mainly gets mentioned when a boat is being sold / purchased!

In any event whilst not normal or great, pretty much all boats have some somewhere - to me it is a scale thing as localised can also fix the underlying problem (if can be arsed!), designers / builders rarely get everything 100% right......at least not for the 2nd decade plus.

[Adventurebound]

A cheap common method of determining the integrity of a composite is to tap on the surface with a coin and listen for the dull thud. This indicates significant delamination and other damage. From my experience the gel coat can display significant damage, but after grinding it away the fiberglass is intact. Your coin test tells no lies if used properly.

[GordMay]

Originally Posted by Adventurebound

A cheap common method of determining the integrity of a composite is to tap on the surface with a coin and listen for the dull thud. This indicates significant delamination and other damage. From my experience the gel coat can display significant damage, but after grinding it away the fiberglass is intact. Your coin test tells no lies if used properly.

Hammer-Sounding a Hull (Tap-Test):

The methodical process of Tap-Testing or Hammer-Sounding a hull leaves a lot of room for interpretation, which only comes with experience.

While the layman may not to be able to interpret the exact tonal qualities returned, you should be listening for any sudden change in sound.

Lightly tap the hull with a clean*, lightweight (4 oz?) plastic (or rubber) hammer, hitting the hull squarely (to avoid leaving marks). Generally, begin your tapping in a visually “good” location, higher on the hull. This should give you a baseline reference.

* I wrap the hammer head in a clean cotton scrap of rag (secure /w elastic hair band)

As the hammer strikes the fiberglass hull, a clear, crisp report should be heard.
Good, dry, solid laminates give a clear, crisp, higher pitched return (ring), and the hammer will be lively, springing back with each tap.

If the report is dull or dead, and sounds like a watermelon, there may cored material that is wet.

Cored hulls return less ring, and wet laminates gives an even lower dead tone (thud).
Bulkheads, stringers, and grid liners also return lower dead tones, somewhat like a slight echo or drum sound.

Place your fingertips near the strike location, feeling for a sharp crisp vibration (tingling).
Your eyes should also be focused on this area, looking for blemishes, disturbances, discolorations, etc.

[cagney]

margav

Did you check the state of the mast support down below?
IIRCC there is a flat square piece at the top of the mast support pole, that is bolted through the ceiling/deck. Check for cracks in the welds between the flat piece and the pole, or for recent repairs.
If you find any, that will be a clear indication of "oil-canning". Squeeze on the topsides (going through a big-ish wave) leads to the mast step is pushed upwards.

This is, in my mind, a possible cause of the cracks.

Thomas