Advice Welcome: Purchasing 40ft Catamaran with wet core

[MartinR]

Boat Hulls - Cores and Structural Issues: Online Articles by David Pascoe, Marine Surveyor

[Montanan]

Honeycombs have a relatively small area for the
skins to bond to, producing weak core/skin bonds
and poor fatigue resistance. The open cell structure
of honeycombs is susceptible to water infiltration
and bond degradation. $0.02

[Ken Z]

Not seeing the boat or know location it s hard to be precise, but I think you should walk away. The damage is probably more than is visable. The labor of repair could be a lot. Resale could be compromised, and if surveyed disclosure, although not all are honest. I would advise bailing out. I have done and do extensive work on boats and I bail when asked, told to use bandaids.

[DerekKelsall]

Originally Posted by sailhand

For my money walk away and cut your losses unless you want to spend time in a boatyard. It might only be water but the constant action of waves at sea will eventually cause it to delaminate it there is enough water in there. Are you really gonna be confident on a rough ocean passage in this boat. Polycore or honeycomb is definitely not the best material for a bridgedeck in a wide low heavy cat, and given that there is a lot of fitout on the bridgedeck it will be a massive job and mostly overhead to repair it. I was wrong actually, i wouldnt walk away id RUN. One of the ways to remove a hull from a mold is to put water between the mold and the hull as water will not compress. You push on the inside of the hull and it forces the water to spread between the hull and the mold breaking it free in the process. This is the same type of hydraulic action that delaminates glass from cores and it is in the bridgedeck and hulls, i say again "RUN"!!!!!. New sails and a perfect fitout wont matter when the boat falls apart. If it delaminates you lose nearly all your structual strength, and if it is as you describe it will delaminate if it hasnt already.

A few years back, a few companies were promoting plastic honeycomb as a better and cheaper alternative to PVC foam. My tests showed that water travelled between the cells. ie there is not a full seal of skin to core. Not good enough in my view, when PVC foam and Corecell have proven to be 100% reliable over decades and no down side. Thin skins cannot be guaranteed to keep water out of the core anyway. Freezing could be disaster. Happy boating, Derek.

[gulfcoastsailor]

omg... another topic question that leaves me scratching my head. I have a file full of them.

[Scout 30]

Originally Posted by 44'cruisingcat

Everything is repairable.

This is not true. If the repair is not financially feasible it is technically not repairable.

It appears that this may be a systemic problem. I would be wary of this brand.

[Montanan]

Reference articles: Boat Hulls - Cores and Structural Issues: Online Articles by David Pascoe, Marine Surveyor

[Montanan]

Another reference article:

Cored Hull Bottoms

[Scrimshaw4]

Run, don't walk away and find another broker while you're at it!

[JasonS]

Hi,

We have a 1999 Manta 40 and absolutely love it, so would not give up on the brand and there are several currently on the market. Awesome owners group will help you with all sorts of issues.

I'm not clear from your post exactly where you are finding wet core. Pat Reischmann who has been involved in the composite technology since it first began designed these boats and he is still around and actively responds. I'd recommend that you reach out to him to discuss findings and get his opinion and what might need to be done. That way you can make an informed decision. It's a huge purchase and you want to make a good choice. Pat's email is preischmann@msn.com.

FYI - all elements of the Manta's were vacuum bagged. Hull, deck and bulkheads utilized a varying schedule of traxial, biaxial and unidirectional cloth applied with isophthalic and vinylester resins. Below the waterline, the hulls are solid glass and vinylester; above the waterline and in the deck, Nida-Core polyproylene honeycomb which reduced weight and increased stiffness and strength. Aluminum backing plates were inserted into the actual layup in many cases. The hulls-to-deck used 3M 5200 adhesive sealant, mechanical fasteners on 10-inch centers and glass tabbing. I've found our boat to be very well-build, stiff, and after 19 years, few cracks even in the now getting old gelcoat. I've seen many other cats that are newer with large cracks, severe gelcoat crazing, and many other issues.

When we purchased our Manta almost 6 years ago, the only moisture readings we got showing any dampness were around a portlight and in the two front hatches. Doesn't surprise me with the two front hatches (which are nidacore) as the perko type locks that seal these hatches leak. Manta really should have ground out some of the Nidacore, epoxied around the holes and then inserted the latches. It's been on my list to take them apart and do just that, but that's a really small issue.

I believe much of the rounded bridgedeck above the galley/main cabin is solid fiberglass. I don't believe there is any nidacore there but I could be wrong. Possible that some water got in around the hatches??? All this being said, I haven't heard of significant wet core issues with any of the Mantas so definitely worth investigating or moving on to another one. We seriously looked at 5 Manta's, passed quickly on 2, lost one to another buyer and then finally settled on Breathe, Hull #49.

Good luck and hope you'll be part of the Manta family. Definitely join the Manta owner's forum at mantaowners.org and our Manta Owners Facebook page once you purchase. There's also a Manta WannaBe on the owners Forum, MantaTech. You can post your questions there and also let people know that you are searching for a Manta. You never know when someone is ready to move on.

Jason
Breathe
1999 Manta 40, Hull 49

[sailingchiro]

Sailing a boat that has problems that could never be repaired on long passages is uncomforatable at best. A wet hull is a very expensive problem that will never get repaired because it would take recoring. How in the world do you recore? By stripping off layers of fiberglass and putting new fiberglass over dry core. Absolutely not a DIY project.
I had my boat repainted recently, essentially the same size boat as the Manta. The bids ranged from $30,000-40,000. I only had small areas of soft core on deck. I am guessing $50,000-60,000 to recore that Manta. Find another boat, take your money and buy new rigging, sails, engines, etc. but don't pay to recore a boat. Please. Stinks for the previous owner. Just don't make it stink for you after you purchase and have no idea how to get rid of the thing.

[sailingchiro]

Oh, and by the way, thank that surveyor with a nice bottle of scotch. He earned his money!

[nomadsailing]

Originally Posted by LeeV

I'm amazed that you even did this: "this was identified by:
First clue: pulling 3 fasteners out of forward starboard cabin sole - water immediately weeped in from the holes"

Unusual to walk through the boat and pull fasteners out of the sole; what made you even think to do so? Certainly glad you did! :-)

Just a thorough surveyor I guess. Happy he did. But I imagine it was still blinding obvious from the moisture meter from the outside anyway.

[nomadsailing]

Thanks all for the advice/information.

all taken aboard and much learnt!

[texpie]

Originally Posted by Scout 30

This is not true. If the repair is not financially feasible it is technically not repairable.

It appears that this may be a systemic problem. I would be wary of this brand.

I’m intrigued by the statistical data you have used for your conclusion. I’m very familiar with this brand and this is a statistical outlier regarding Mantas. Please enlighten the forum about the data you are using to support your conclusion.