Opinions Highfield CL340 RIB with cracked aluminum hull

[rescher]

I'd like some advice from people who are knowledgeable about aluminum RIB dinghies.

I've been shopping for a new dinghy and a dealer has offered me a "deal" on a 11' Highfield CL340 dinghy that was replaced under warranty. The dealer says the dinghy was only used for six months, but to my eye it appears to be older. I have been offered this dinghy for $2500US as is.

The dinghy has a 1" crack (see pictures) on the port side just forward of the transom. The crack extends under the area where the hypalon is bonded to the hull. This implies to me that the crack cannot be welded because it is so close to the hypalon. The dealer told me the crack can easily be fixed using G/Flex epoxy. There also appears to be a similar crack forming on the starboard side in the same position, just forward of the transom.

How did the cracks form? The dealer tells me he suspects the owner used too large of an engine. He speculates that put too much stress on the transom, and hence the cracks.

What are your thoughts? Should I buy this dinghy? I live aboard an older catamaran and my wife and I and four kids are planning to cross to the South Pacific from Panama next year. We are looking to replace our 10+ year old dinghy with something newer that will, hopefully, require less maintenance (ie. patching) than our existing dingy.

Thanks for the help.

Rick aboard s/v Aphrodite
www.aphrodite.cat

[KD8NPB]

Originally Posted by rescher

How did the cracks form?

Untrained Chinese welders.

Puddle is too large for the substrate... effectively, both surfaces have now been overheated. The cracks will likely continue to propagate through the extremities of the weld as the aluminum undergoes use and heating/cooling cycles.

[hobopacket]

I would pass. Unless the deal was a heck of a lot better than they offered. More like 1000$. Then use a product like marine Tex. I worked for a city renting out 30+ aluminum johnboat's. They would develop cracks and holes and what not. The marine text product worked very well. Stays fairly flexible.

[KD8NPB]

Originally Posted by hobopacket

I would pass. Unless the deal was a heck of a lot better than they offered. More like 1000$. Then use a product like marine Tex. I worked for a city renting out 30+ aluminum johnboat's. They would develop cracks and holes and what not. The marine text product worked very well. Stays fairly flexible.

GFlex 655K kit works a lot better than marinetex.

I've peeled it out of mixing cups...you can almost fold it back on itself before it snaps. Lots of elongation before failure.

[Fence Man]

Originally Posted by KD8NPB

Untrained Chinese welders.

Puddle is too large for the substrate... effectively, both surfaces have now been overheated. The cracks will likely continue to propagate through the extremities of the weld as the aluminum undergoes use and heating/cooling cycles.

X2. It could be fixed, but it would be expensive to do it right. Filling the cracks with goo will stop it from leaking, only until the cracks worsen.

[a64pilot]

If you buy it, be sure to stop drill the cracks first before sealing them. If not stop drilled a crack will often continue, the hole relieves the stress riser at the end of the crack, usually. Sometimes if the condition that originally caused the crack continues, the crack will grow past the stop drill.
I can see how too big / heavy an engine would cause the problem

[twohapence]

Walk away and spend your money elsewhere as this looks like an expensive mistake in the makng.

[Jim Cate]

Depends somewhat on what size engine you intend to use on the boat. If content with something like <5 hp, and eschewing planing, and if you follow A64's advice about stop drilling, it might well last a longish time. With a 15, heavy loads from your large crew and planing through rough seas, I'd expect further issues.

I would personally not buy it, but YMMV.

Jim

[JPA Cate]

In your circumstances, Rick & family, I would not buy it either. Your plan is to play and have fun with your family. As you get away from civilization and out further into the Pacific, your dinghy is your car, your pick-up truck, your means of exploring while the mother boat is home in a safe anchorage. You really want it to be bullet proof; and, carry a spare prop in the dinghy bag.

In terms of used RIBs, generally, we have some friends that got a used Caribe, about 10 yrs ago, and it is still going very well.

There are many dinghies in the world, some of which are used, and for sale. I hope you can find a good used one, or, if not, then spring for a good new one. There are better ways to economize.

Ann