Oyster Problems?

[Exile]

Originally Posted by boatpoker

If I spent the time to go through my files I could show you hundreds of photos that would make any reasonable person wary about buying a boat. How about the new 45 catamaran found to be only 3mm (not a mis-print) thick around the saildrive.

Some of you wonder about the cynicism of those of us in the business. I can assure you it is well earned.

I think cynicism is in fact well-earned skepticism! Yes, there does seem to be a lot of consensus from the pros. Both on the forums and from the anecdotal encounters I've had at various yards. Just look at the 'Yard Guys' thread!

While I'm not in the market for a different boat and wouldn't be inclined towards most of the newer crop in any event, as a sailor I would much prefer to believe that the latest incarnations are well found. They are still being purchased in large numbers, and many have done impressive voyages on them, but I suppose that only gets you so far. The nature of cruising makes it difficult to track problems & failures.

[Jim Cate]

Originally Posted by boatpoker

If I spent the time to go through my files I could show you hundreds of photos that would make any reasonable person wary about buying a boat. How about the new 45 catamaran found to be only 3mm (not a mis-print) thick around the saildrive.

Some of you wonder about the cynicism of those of us in the business. I can assure you it is well earned.

Holy cow!

And yet we have folks assuring us that the "modern, robotic construction methods" employed by Lagoon and others of the Beneteau group assure us of a quality product, far better than hand made items.

Go figger...

Jim

[neilpride]

3 mm are 2 layers of 300 Gr matt...

[Just Another Sa]

Originally Posted by neilpride

3 mm are 2 layers of 300 Gr matt...

Yes, but only with 8% fiber ratio by volume.

3600 grams/sqm is 3 mm thickness with 48 % fiber ratio by volume, a more typical value if vacuum bagging or some better method is used.
More than enough for a drive leg as long as it doesn't hit anything solid.

[Muckle Flugga]

Merry Christmas, Buon Natale, Joyeux Noel!

[Muckle Flugga]

Originally Posted by Just Another Sa

Yes, but only with 8% fiber ratio by volume.

3600 grams/sqm is 3 mm thickness with 48 % fiber ratio by volume, a more typical value if vacuum bagging or some better method is used.
More than enough for a drive leg as long as it doesn't hit anything solid.

You mean like one of the tens of millions of solid things floating around "out there"?

[Exile]

Originally Posted by Just Another Sa

More than enough for a drive leg as long as it doesn't hit anything solid.

I think that's the point, at least for a boat used in a cruising application.

[Exile]

Woops, MF beat me to it. Must be those great minds thinking alike again.

[boatpoker]

Originally Posted by neilpride

3 mm are 2 layers of 300 Gr matt...

Looked like chop to me, couldn't tell if it was chopped mat or gun

[Just Another Sa]

Originally Posted by Muckle Flugga

You mean like one of the tens of millions of solid things floating around "out there"?

They should not be allowed to hit the drive leg by design.
Put that extra weight into the keel structure which is going to hit those solid things, and not to somewhere else that is (or at least should be) protected by the keel. Pretty easy to add a horizontal string from the bottom of the leg to the back edge of the keel preventing any hits to the leg, while being much lighter than all the laminate needed to make the leg and the structure around it capable of withstanding the hits.

[minaret]

Originally Posted by Just Another Sa

They should not be allowed to hit the drive leg by design.
Put that extra weight into the keel structure which is going to hit those solid things, and not to somewhere else that is (or at least should be) protected by the keel. Pretty easy to add a horizontal string from the bottom of the leg to the back edge of the keel preventing any hits to the leg, while being much lighter than all the laminate needed to make the leg and the structure around it capable of withstanding the hits.

Guess you missed that big Lagoon which sank because it wrapped a line around the prop which was tied to a cleat on deck. The side load on the drive leg tore the bottom out (it probably looked like the layup in question, certainly couldn't possibly have been any less ), and the boat sank. It's easy to pretend at a nice clean drawing board that things like this shouldn't happen "by design", but IRL they most certainly do.

[Just Another Sa]

Originally Posted by minaret

Guess you missed that big Lagoon which sank because it wrapped a line around the prop which was tied to a cleat on deck. The side load on the drive leg tore the bottom out (it probably looked like the layup in question, certainly couldn't possibly have been any less ), and the boat sank. It's easy to pretend at a nice clean drawing board that things like this shouldn't happen "by design", but IRL they most certainly do.

It didn't sank because of the rope around the prop causing a leak, but because it wasn't buoyant like it should have been, just as a multihull always should be.
The engine compartment was also supposed to be watertight, and it wasn't.
The propeller also was way too strongly attached to the leg. It should have broken off with much less force than the leg attachement can support, which is easy to do with a shear pin.
That's how outboard props and their attachements are designed, and the same should be done with saildrives.

[minaret]

Originally Posted by Just Another Sa

It didn't sank because of the rope around the prop causing a leak, but because it wasn't buoyant like it should have been, just as a multihull always should be.
The engine compartment was also supposed to be watertight, and it wasn't.
The propeller also was way too strongly attached to the leg. It should have broken off with much less force than the leg attachement can support, which is easy to do with a shear pin.
That's how outboard props and their attachements are designed, and the same should be done with saildrives.

Whole lot of "should have" in there.

[Just Another Sa]

Originally Posted by minaret

Whole lot of "should have" in there.

That's also the case for most accident investigation reports. I don't find that surprising.

[neilpride]

So now 3 mm are enough if, if, if, if , if......