Cored or un-cored hull?

[Hardhead]

Originally Posted by Davidhoy

Thanks Ann! It’s a bit of a roller coaster ride right now, trying to deal with the other guy’s insurance company. Fortunately there’s no question of fault, as my boat was docked at the time. The damage in the photo I posted is only the most obvious “wound”, there’s much more. I hope you’re right, and that things will be made right, but right now it’s looking like we will end up with the short straw. Why does the law seem to protect the insurance companies more than us?!?

-David

I'm a lawyer, and unfortunately, I can tell you that insurance carriers will play games and chisel nickels to no end, unless they know you have a real ability to actually sue them.

I'd try talking to a lawyer ASAP, before any holes get dug deeper. It's hard to change the trajectory of an established case. Good luck and hang in there.

[boatpoker]

Originally Posted by Davidhoy

Thanks Ann! It’s a bit of a roller coaster ride right now, trying to deal with the other guy’s insurance company.

Why are you dealing with the other guys insurance company ? That is the responsibility of your underwriter.

[hellosailor]

david-
An insurer has limited liability, as per the policy. But unless the policy-holder has no assets, that just means you sue them directly for the entire balance and try to collect on whatever their insurance doesn't cover. Whether you do that yourself, or with an attorney or your insurer helping, it is still the same process. You can collect from their insurer, and them have their boat seized and auctioned off to pay toward the balance remaining. Or their house, or their bank account, or 10% of their wages for the next twenty years. Plenty of options, if this is news to you, get an attorney at least for a consult.

Cored hulls and decks provide acoustic and thermal insulation, as well as making the boat substantially lighter and faster and stiffer. And yes, substantially cheaper than using the extra coupla hundred gallons of resin and all that fiber. One can easily argue that ANY frp hull is a weak hull, compared to other options. So coring? Not entirely pointless or useless.

[boatpoker]

Originally Posted by hellosailor

And yes, substantially cheaper than using the extra coupla hundred gallons of resin and all that fiber.

I am not a fan of cored hulls for a number of reasons however I completely disagree with this statement. Core materials are not cheap and there is much more labour involved than an all FRP hull for the same nominal requirements.
They are most often more expensive to build if done to a reasonable standard.

[coopec43]

Originally Posted by FPNC

The skill required to bed core properly and limit unbonded and void areas in the core is seldom seen in marine manufacturing.

I built my yacht using a male mold so I was laying glass /resin onto the Airex core. I can assure you there was no trouble bonding the glass to the foam!

But then using a female mold it would be a different story and it could present problems. Divinycell have a special thick resin called Divyllette(?) which I think could overcome the problem

Clive

[Dockhead]

Originally Posted by boatpoker

I am not a fan of cored hulls for a number of reasons however I completely disagree with this statement. Core materials are not cheap and there is much more labour involved than an all FRP hull for the same nominal requirements.
They are most often more expensive to build if done to a reasonable standard.

This is a fact. And to make an excellent cored hull is really, really expensive, which is why you typically find them nowadays only in high end boats.



Also, does anyone believe GRP is weaker than other materials, like steel, alu, or wood?


GRP has higher specific strength than steel or aluminium. Any given boat hull is as strong as it is designed to be. It is not particularly difficult to make a GRP hull immensely strong. The main challenge is making the hull thick enough to be stiff -- and that is where coring comes in.

[deluxe68]

Originally Posted by boatpoker

I am not a fan of cored hulls for a number of reasons however I completely disagree with this statement. Core materials are not cheap and there is much more labour involved than an all FRP hull for the same nominal requirements.
They are most often more expensive to build if done to a reasonable standard.

Pacific Seacraft sells boats with solid hulls, but they offer cored hulls as an option. I am pretty sure they have high standards for construction.

[Cheechako]

Originally Posted by coopec43

Despite what the experts say?

What many don't think about is theory vs reality. In theory a cored hull may have better characteristics. But that may only apply in a perfect world. And it may be true for some percentage of boats in the real world.
Manufacturers have forever had a lot of trouble finding good people to work in the "layup" department. Why? Because it's a dirty, sticky noxious job. I know people who worked there. So it ends up being a job that newbies or starters work for a while.
The more complicated a layup becomes, the less you want an ex burger flipper who is high on fumes doing it.

Decks are nearly always cored now. My experience is, there are more often than not, problems with a cored deck when you are buying a boat. I have had 4 surveys done on boats in my time. Every one of those had at least a small area of concern. One boat was saturated and about 7 years old. Another I got to read a survey done before my prospective purchase and it was pretty much a total loss. (Celestion 51).

So it's the real world that is a problem, not the theory. A fully engineered carbon composite boat in the America's Cup sank in 2 minutes by breaking in half in light airs. The theory was correct I imagine.
It's all just a matter of reducing risk.

I'm not willing to say you cannot get a good cored boat, just saying that you better be lucky and intensely involved in inspection and purchase.

[Colin A]

Originally Posted by boatpoker

I am not a fan of cored hulls for a number of reasons however I completely disagree with this statement. Core materials are not cheap and there is much more labour involved than an all FRP hull for the same nominal requirements.
They are most often more expensive to build if done to a reasonable standard.

Have to agree with this. The labor and materials costs generally would make most cored hulls more expensive. If you add the done right qualifier there is no question a cored hull is more expensive.

[Colin A]

Originally Posted by Cheechako

So it's the real world that is a problem, not the theory. A fully engineered carbon composite boat in the America's Cup sank in 2 minutes by breaking in half in light airs. The theory was correct I imagine.
It's all just a matter of reducing risk.

On a side note I met one of the guys that built that boat a little while after that happened. He told me their motto during construction was "if it doesn't break we made it to heavy" oops.

[a64pilot]

No, a cored hull is less expensive than a solid hull that is just as stiff.
All things being equal, however an exotic cored hull can be astronomically expensive.
Then there were many solid hulls that were essentially junk, remember “chopper” guns?

So the answer is as always, it depends. It depends on who did it, how it was done and which materials were used.

My take on it is, if it can get wet, it’s going to get wet eventually. I don’t think most Cats are going to age gracefully, cored hulls is a big reason I think that.
Time will tell.

Remember balsa decks that were end grained blocks couldn’t get wet, cause they were individually sealed blocks, only the block where the leak was could wet, right?