Fibreglass vs Aluminium Impact Strength

[atoll]

Originally Posted by goboatingnow

In practice only a very small number hit reefs in the first place. After the owner has paid the repair bills on the steel boat to bring it back to full cosmetic standard , including removing half the interior to allow welding , then t he full two pack repaint. I suspect he'd prefer it went to the bottom. !!!


My yard where I keep the boat specialised in steel repair. It's far more costly to repair steel to the original cosmetic standard, yet its relatively easy and cheap to do so with GRP. In fact most average cruisers would have the skills to repair non cored GRP to a good standard. Few could do so in steel with a high quality LPU finish.


Dave

as much as i enjoy your many astute posts,on this one i beg to differ, having spent many years in hurricane areas,and tropical waters.

i will never forget sailing into the lagoon in st martin after "hugo" and seeing all those fiberglass boats ground to a pulp on the shoreline.

the numerous glass boats wrecked in the red sea "at anchor" when the wind changed.

and all the grp wrecks on numerous reefs around the world that have been holed from minor groundings,that had they been metal would have survived with minor inconvience.

[DeepFrz]

FG success in boat building is because it is cheaper and a mold can be used over and over. That doesn't make it a better material. Now, vacuum resin infusion using vinylester resin or epoxy resin and e-glass does make a very good hull, and now you are talking big bucks once again.

[goboatingnow]

Originally Posted by DeepFrz

FG success in boat building is because it is cheaper and a mold can be used over and over. That doesn't make it a better material. Now, vacuum resin infusion using vinylester resin or epoxy resin and e-glass does make a very good hull, and now you are talking big bucks once again.

The vast majority of large scale production builders have switched to close mould , vacuum infusion with vinyl ester and exotic fibres in collision areas. European Heath,regulations have made open moulding virtually a thing of the past and low solvent vinyl ester is prevelant

Dave

[Kettlewell]

I think it is pretty routine to hit stuff. I've hit rocks within sight of my home mooring! Shallow river, very low tide, and I was in the wrong place, but it does happen. Despite all our wonderful anchors, boats do drag, storms still happen, and people make mistakes. When we were down in the San Blas a single hander dragged up on the reefs and lost his boat and almost his life. We helped rescue another small Colombian sailboat that sailed up on one of the reefs. I helped get a big trawler off the coral after he had dragged aground in a big blow. A Valiant 40 dragged and went up on the reef next to us during a 56-knot chocosana, and required pretty major fiberglass repairs. A steel schooner dragged onto the reefs and only got off with some major work. A Dutch boat hit an offshore reef that was only barely above water and poorly charted. A backpacking boat sunk on an offshore reef and the passengers managed to swim a mile or two to shore. And, all of that was within one year!

[noelex 77]

Originally Posted by DeepFrz

FG success in boat building is because it is cheaper and a mold can be used over and over. That doesn't make it a better material. Now, vacuum resin infusion using vinylester resin or epoxy resin and e-glass does make a very good hull, and now you are talking big bucks once again.

I agree. The pity is the construction you talk about would maybe double the cost of the hull, but given the that the hull is only about a 1/3 of the cost of the finished boat would not be a great deal more. Leave off the teak deck and you are close to breaking even.

[noelex 77]

Originally Posted by goboatingnow

The vast majority of large scale production builders have switched to close mould , vacuum infusion with vinyl ester and exotic fibres in collision areas. European Heath,regulations have made open moulding virtually a thing of the past and low solvent vinyl ester is prevelant

Dave

Very few manufactures are using vinyl ester, or the better epoxy resins thought their layup.
There are exceptions Morris, Apogee Tartan etc, but these manufacturers use cored materials, with the associated delamintion problems.

What about a solid epoxy, or at least vinyl ester hull?

Unfortunately the vast majority of boats are constructed with polyester resin with a token vinyl ester layer close to the water.

Give us a strong easily repairable, waterproof hull with good fittings an encapsulated keel, or at least lead, strong chainplates and rig.

[goboatingnow]

Originally Posted by atoll

as much as i enjoy your many astute posts,on this one i beg to differ, having spent many years in hurricane areas,and tropical waters.

i will never forget sailing into the lagoon in st martin after "hugo" and seeing all those fiberglass boats ground to a pulp on the shoreline.

the numerous glass boats wrecked in the red sea "at anchor" when the wind changed.

and all the grp wrecks on numerous reefs around the world that have been holed from minor groundings,that had they been metal would have survived with minor inconvience.

Atoll. The fact is there are so few metal leisure yachts sailing that comparisons are very hard to draw. For example I've seen a high quality steel boat hit a rock and split a weld. , she sank, earlier in the Month a GRP boat also hit it, she survived.

I've seen a steel boat aground on a reef , she was intact, because of that she was stripped by the locals of everything in her as her weight proved impossible to get her off. The hull was fine, the boat however was abandoned. The net result was a full loss situation.

I've seen quite minor damage to steel boats require a full LPU awlgrip repaint costing thousands , removal and rebuilding of interior cabinetry to allow welding, and the liberal use of epoxy resin to restore the contours as panel beating was going to take too much time.

We had a steel yacht that fell off its cradle , the resulting panel damage was minimal, and the boat perfectly Sailable. The owner wanted his pride and joy restored to the pre accident condition, this resulted in major panel surgery, interior cabinetry removal, and a full sand blast, multiple re coat , repaint job, its cost $$$$$. The equivalent damage in a similar GRP one was a few fillings and a compound , the result was indistinguishable from new.

Build it like a fishing trawler, steel is brilliant. , build it like a car and its as similar delicate. If I want a boat to go ice bumping in the Artic, ill get steel, built like a shithouse and painted by a man with a brush. It's will be brilliant, I can fix it with me stick welder , it will however be a ball of rust in 5 years, be worth nothing and look ****.

Steel or aluminium is great in abstraction, but in a high quality finish its an expensive and difficult to justify material with dubious real life advantages. Not to mention the huge additional cost etc etc.

[sailronin]

"Why are ships built of steel? Because whales bounce off of them."
Quote from one of my ship captain friends.

[DeepFrz]

We had a steel yacht that fell off its cradle , the resulting panel damage was minimal, and the boat perfectly Sailable.

I have seen a FG luxury trawler that when the aft strap on the boat lift parted the aft section dropped 12 to 18" and the boat was a write off...total.

Maybe we all see what we want to see...

[noelex 77]

Originally Posted by goboatingnow

Atoll. The fact is there are so few metal leisure yachts sailing that comparisons are very hard to draw. .

I think this would be accurately stated as " There are so few metal leisure yachts in the USA"
There are plenty in the worlds cruising grounds.

[goboatingnow]

Originally Posted by noelex 77

Very few manufactures are using vinyl ester, or the better epoxy resins thought their layup.
There are exceptions Morris, Apogee Tartan etc, but these manufacturers use cored materials, with the associated delamintion problems.

What about a solid epoxy, or at least vinyl ester hull?

Unfortunately the vast majority of boats are constructed with polyester resin with a token vinyl ester layer close to the water.

Give us a strong easily repairable, waterproof hull with good fittings an encapsulated keel, or at least lead, strong chainplates and rig.

" Epoxy construction has in the past only really been used for racing yachts where strength and reduced weight were more important than cost. What was less important to the racers was osmosis prevention, which is another quality of Epoxy resins. Hanse build ALL of the their models using epoxy based vinylester resins AS STANDARD, which further adds to the strength of this stunning range of yachts"

A major medium market production builder.

[atoll]

Originally Posted by goboatingnow

Atoll. The fact is there are so few metal leisure yachts sailing that comparisons are very hard to draw. For example I've seen a high quality steel boat hit a rock and split a weld. , she sank, earlier in the Month a GRP boat also hit it, she survived.

I've seen a steel boat aground on a reef , she was intact, because of that she was stripped by the locals of everything in her as her weight proved impossible to get her off. The hull was fine, the boat however was abandoned. The net result was a full loss situation.

I've seen quite minor damage to steel boats require a full LPU awlgrip repaint costing thousands , removal and rebuilding of interior cabinetry to allow welding, and the liberal use of epoxy resin to restore the contours as panel beating was going to take too much time.

We had a steel yacht that fell off its cradle , the resulting panel damage was minimal, and the boat perfectly Sailable. The owner wanted his pride and joy restored to per accident condition, this resulted in major panel surgery, interior cabinetry removal, and a full sand blast, multiple re coat , repaint job, its cost $$$$$. The equivalent damage in a similar GRP one was a few fillings and a compound , the result was indistinguishable from new.

Build it like a fishing trawler, steel is brilliant. , build it like a car and its as similar delicate. If I want a boat to go ice bumping in the Artic, ill get steel, built like a shithouse and painted by a man with a brush. It's will be brilliant, I can fix it with me stick welder , it will however be a ball of rust in 5 years, be worth nothing and look ****.

Steel or aluminium is great in abstraction, but in a high quality finish its an expensive and difficult to justify material with dubious real life advantages. Not to mention the huge additional cost etc etc.

i am probably biased,as for me visiting some of the more remote parts of the world,endurance is more a factor than elegance.

above the waterline i have no paint,apart from the decks,corrosion is not an issue,neither is lying along side a fishing boat in a third world port.

if you want a pretty boat then go fiberglass by all means,what suits me is what i have and after 2 circumnavigations it has proved its worth,and paid for itself as an expedition boat.

[Andrew Troup]

Originally Posted by europaflyer

Interesting. I always believed that since fibreglass is more brittle than aluminium (or steel) it would shatter in an impact, while aluminium would only bend..... What do we reckon, true comparative test or not? ...

I don't find this a convincing test, because of the proximity of free edges.The aluminium adopts an origami topology which it could not do if restrained along all edges. (As any portion of a hull invariably is: if there's a free edge nearby, it's heavily framed).
You'd never see a fold like this in an impact fracture on a hull, tank or pressure vessel engineered from metal.

The fibreglass panel on the other hand, being a resilient material, benefits from the free edges: they enable the panel to act like a spring, storing the energy temporarily as it deforms elastically, then returning it to the (unrealistically light, high velocity) impacting element.
If properly and realistically restrained it would be unable to do this to the same degree.

I'd be more impressed if the same panels had been gripped immovably all round their edges, and a more massive, slower impacting element used to impart the same energy. I suspect the results would be very different, but then of course you would not see them in a video made by a fibreglass boat vendor.

[goboatingnow]

Originally Posted by noelex 77

I think this would be accurately stated as " There are so few metal leisure yachts in the USA"

Noelex, walk around las palmas ( well last week ) walk around Port Vauban, walk around les Sables , Brest , visit dusseldorf or Southampton, tell me how many metal sailboats under 50 feet you saw. Then remove Ovni and alubat, now do that again. You will not need more then one hand.

Sheesh.

Dave

[goboatingnow]

Originally Posted by atoll

i am probably biased,as for me visiting some of the more remote parts of the world,endurance is more a factor than elegance.

above the waterline i have no paint,apart from the decks,corrosion is not an issue,neither is lying along side a fishing boat in a third world port.

if you want a pretty boat then go fiberglass by all means,what suits me is what i have and after 2 circumnavigations it has proved its worth,and paid for itself as an expedition boat.

I salute your vessel , but its not the norm Atoll and it confirms exactly what I said.

Me I like a strong functional AND pretty vessel. After all its my " fancy"

Dave