Repeating cracks in the bottom of the hull

[bret]

What do you all think about this? Anyone experienced with recurring hull cracking?

The last two years (the length of time we've owned the 2000 moomba mobius V - we bought it used) we have been having issues with cracking near the lowest point at the bottom of the boat - right below where the ski locker ends and the fuel tank begins. (We believe the previous owner sold us the boat in this condition without disclosing the problem as it looked like it had been patched the first time we tried to have the crack fixed) The crack is a V shape that spread up the boat but is less than a few inches long on each side.

We had a fiberglass person patch it twice now which involves removing the fuel tank and patching it inside and outside, and both times over the summer the crack has started to appear again. The second time we had it patched the inside patch held, but it still started to crack again. He is recommending he re-fiberglass the length of the boat on the bottom figuring that there is just too much flexing going on between the hull layers and a smaller sized patch isn't enough. It is going to be a rather large sum of money, and I'm only willing to commit if it will solve our problem permanently.

Below are 3 images, one that just shows our boat looking all nice, and the other 2 pics are of each side of the bottom of the boat showing the crack as it creeps up the hull. Again, the location is right below where the ski locker ends and the fuel tank begins.

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[bergermaister]

Remind us - how many hours on this hull?

I'm curious about how much stress your boat sees - running w/ front ballast slammed? lots of rough water? what kind of supports it sits on in the lift? Basically anything that could cause a lot of stress/load in specific areas resulting in the cracks starting and spreading. Did the cracks start when it lived on the trailer or just since it's been in the lift?

[kaneboats]

Did the previous owner keep it in the water all season? Or on a lift?

[bret]

The previous owner trailered it. We use it on a lake that is usually relatively calm and smaller in size. We have no fat sac in the bow, but we do have an 1100 one in the ski locker. We noticed cracking before we had any ballast system installed. It sits on a shore station with two bunks that run lengthwise.

The only time we fill the center sac pretty full is when we surf. We have a 750 that we fill next to the engine and a 400 that sits on the seats for additional weight in the rear.

[ryan_8099]

Boat has about ~620 hours on it. This has been extremely frustrating for us as it has now delayed us getting into the water for 2 years and it still is not fixed...We have already put a bunch of money into this fix and it just keeps happening.

[maxpower220]

Do you have issues with the window closing properly? Are there any other indications that the hull is flexing too much?

Gel coat is very stiff and is prone to crack. There are different epoxies that can be used in fiberglass to allow flex or be rigid. Just a thought, that the repair was made with the wrong epoxy and is causing this.

I would get another opinion from a different fiberglass shop.

[bret]

We do have some issues with the window (closes tight), but if I recall correctly it is also bent slightly on one side. You are thinking the fiberglass needs more flex in it, correct?

[maxpower220]

I really don't know specifically. I do know that most fiberglass is put in with polyester resin, which isn't as rigid as epoxy and other type resins. In either case, gel coat doesn't flex, which is one reason for general spider cracks in gel coats.

Really, it was just a thought as to the reason that it may be happening. I can't recall anyone having a repeating issue in a forum before.

You may try calling Skiers Choice, I mean Boarders Choice, and see if they have an input.

[bret]

We called skiers choice the first time we had the crack and it wasn't too helpful. They talked about was drilling a hole in our ski locker to try to remove water at the end of the season, but it didn't sound like they had any suggestions for fixing the cracking. We like the moomba brand, but definitely doesn't give me an incentive to buy another. We know a bit more now, so I might try calling them again but I'm not really that hopeful.

[parrothd]

Those are tiny.. Why are you so worried? It sucks that it happened but nothing you can so about it now. Here's what I found on my last boat, got it cheap and in the dark...

That's about 16inches long, the guy hit something very hard at full speed. My point is yours isn't that bad..keep an eye on it but nothing to worry about, definitely get it insured incase it sinks...I wouldn't mention this thread with the insurance folks.. :D


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