Hull survivability in a collision FRP vs Steel

I have sold about 30-40 steel trawlers and attended survey on almost all of them. "Scars" show up on haulout that present interesting stories where hulls were dented or "doublers" required to patch damage. Hurricanes, groundings, collisions, allisions, have all left their marks with zero water intrusion.

Judy

Do you think sometimes the steel owners think of their boats as tougher and therefore do more banging into things resulting in scars and dents? Much like on likes those with big rub rails seem to bang the docks constantly.

Good point and I do think a steel hull can provide a sense of over-security. The only one in particular that might relate to is the owner of a 65' steel yacht with a 6' draft who did the Great Loop and had a few significant mishaps. However, many were from storm incidents: one was at the dock in Phuket when the tsunami hit and he suffered a knockdown with subsequent paint damage from the docks (he was the only boat to survive in the marina); another was in a hurricane in Fl or he had 2 sailboats break free from their moorings and crash into his boat and subsequently they both sank (he was the only surviving boat in that marina); another was a hurricane in Maine and the 65' boat broke away from the mooring and was tossed ashore (it took numerous cranes to drag it across the rocks several hundred yards back to water.) Recently, a steel trawler had a mechanical problem and needed a tow in bad weather and the 85' steel tugboat inadvertently rammed the hull causing significant dents. Lots more stories...

This is information on steel in isolation - it doesn't offer anything at all in a comparison between steel and FRP.

If you could tell us about steel hulls and FRP hulls you've sold that would at least be something (although strictly empirical).

You're right, but I waited a few days before posting to see if anyone had anything specific to offer and then decided that my input might have been helpful to the o.p.

Everyone knows of fiberglass hulls that have been damaged in hurricanes, collisions, and groundings, but we don't see the reports and YouTubes on steel hulls or their near misses which is where I thought my perspective might be helpful.

I gave a seminar on the differences between the hull materials and searched fairly extensively for data of any kind on the statistics or comparisons and found very little. At that time I asked several boat builders if they had performed any tests and none had. Subsequently one of the builders is planning on doing a steel vs fiberglass test for stress, abrasion, impact, etc. but it hasn't happened yet.

Judy

Considering that that beach was selected for that purpose because it provided the softest grounding possible may have something to do with that, don't you think?

There is a reason they don't do that kind of shipbreaking on the coast of Maine or west coast of Vancouver Island.

Speaking of which, there are dozens of amazing photos of wood, steel, and glass boats perched on rocks in BC and Alaska that can be used to support any argument for any material.

In my opinion, this whole discussion about which material is "better" seems a bit ridiculous. There is no "standard" collision, grounding, or allision so what happens is what happens. There are many reasons to choose one material over the other but worrying about what happens when you screw up is probably among the least important.

I once saw an 18' outboard that ran over the bank at the edge of the lake doing 60 mph, got airborne and landed about 20 feet up in the woods. When the owner, who was drunk, figured out what had happened the engine was still running. Running engine wide open out of water wasn't good for it, but boat had no damage other than scratches. Problem was somehow the boat went between two trees that were angled out but too close at the bottom for it to fit. This was in woods, not near a home. Landowner wanted the boat gone quickly though. Yet, he didn't want a tree cut down. Took several hours to get dollies, turn the boat partially on it's side and ease it out.

I didn't say the beach was soft - like mud - I said the beach was selected because of its inclination, it's geometry old boy, it's all in the angles.

That beach could be made of steel or granite and the ships would ease onto it just as gently.

There's one thing going for steel from the paranoid pov: even at awful quality it's still not likely to have only a tiny fraction of designed strength.
A freak in grp (especially cored) could make it locally little better then waxed paper. To the point of unprovoked failure.
But then again, chances of encountering that in vivo aren't really much noticeable.