And the safest hull material is...

[El Pinguino]

Originally Posted by Steady Hand

Ping,

Thanks for posting the video clip. I really enjoyed it. It was like watching a Monty Python sketch. Hilarious!

About your point about bulk carriers lasting just 15 years:
I recently looked at a list of about 20 commercial freighters and ships (all steel) that were built in 1980s. They were made by a wide range of builders (some in Europe, some in Far East, some in Asia), and they had a variety of types and sizes (all over 200 feet long). They were large ships. They were ALL scrapped after just about 15-20 years (average) use. When I saw that, I was surprised at the short life of the commercial ships.

That was John Clark aka Fred Dagg and John Dawes.... still going after the news on a Thursday evening with some political satire.... in this case sending up Senator Collins who actually had said the ship 'was no longer in the environment'...

Ships are surveyed every 4 years with the surveys getting progressively harder and 20 years was always the killer... bulk ships always had a short life with passenger ships typically being the ones that lasted longest.

[mstrebe]

The Navy keeps ships on average for 30 years. By then, the cancer is winning and the crew spends a lot of time keeping up with it.

On commercial ships, they're not turning the crew to painting, chipping, needle-gunning, and generally keeping the ship up. They just let them rot and write them off.

[FamilyVan]

Originally Posted by mstrebe

The Navy keeps ships on average for 30 years. By then, the cancer is winning and the crew spends a lot of time keeping up with it.

On commercial ships, they're not turning the crew to painting, chipping, needle-gunning, and generally keeping the ship up. They just let them rot and write them off.

You decked on different commercial ships then me. I once did a 93 day trip as a mucker and all I did was chip and paint for 12 hours a day 7 days a week. Good weather- outside, dirty weather stuck down in a pump room or tunnel.

Bulkers built in the 50's and 60's are a common site on the great lakes where the fresh water let's them last.

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[estarzinger]

First fact: the majority of pleasure boat losses happen at 'at the dock'. And statistically wood boats are worst followed by steel, both with potential "hidden problems". Glass is most reliable 'at the dock' . . . it essentially lasts 'forever' with essentially zero corrosion or other degradation problem (blisters and wet core usually don't sink the boat at the dock).

Second fact: IF you design/build to the SAME WEIGHT . . . . the most advance composite can easily be made the 'strongest' . . . and excellent at essentially any engineering criteria you pick (for instance modulus or fatigue) depending on the exact composite design . . . . but also by far the most expensive (by a factor of 10 or more) and most difficult to repair (to full strength). Aluminum will be a close second in strength and much more 'reasonable' in cost. (this is why planes are composite and aluminum). And (usually) pretty easy to repair back to full strength.

Third fact: in common construction, without equalized weights, steel boats are the 'toughest' - abrasion and cut resistant (unlike aluminum), elastic enough to adsorb blows without breaking (unlike common glass), and the easiest to repair to full strength. But steel (in common construction) is heavy (slow) and requires significant maintenance work and has typically has relatively low resale value.

Fourth fact: for normal cruising, any of the materials is perfectly fine if used in a well designed and well built hull. They all work, they all can be excellent, and they all can be terrible. It depends much much much more on design and construction quality than on the particular material. For special purpose uses (like very big or very small hulls, or ice usage or extremely high fatigue usage) it is a bit more complex and there are some material preferences but they are really beyond the scope of this thread.

[tkeithlu]

I agree that there are too many uncontrolled variables in these data to reach a conclusion about safest hull material (I used to teach research methodology). That said, I own a 44' steel trawler. It weighs 60,000 pounds. If it hits anything made of fiberglass, or even a dock, it's going to win. I own steel because I could build in it, and it's high maintenance, but I do worry that fiberglass burns like greased paper.

[RaymondR]

First fact. If the boat is going to sink I for one am very partial to it sinking at the dock where I can just step off.

In the thirty odd years I have been in this yachting business I have witnessed:
one FG boat burn up at sea,

two others which were complete write offs because they were heat affected by the one which burnt up between them in the marina,

the aftermath of one which burnt in the marina, was cut loose and drifted over against a steely and burned up it's mizzen, rubber duck and paint job but did not catch fire,

one in a slip yard which had burnt out but did not sink and was lifted out for insurance purposes then scrapped,

one which burned up whilst being built.

During the same period I have had my own steel boat on a reef without damage, passed one on the beach at Cape Bowling Green which was salvaged, have a friend who spent six weeks on a reef in the south west Pacific until the steely was dragged off by two trawlers, and have a friend who's steely was dragged out of the mangroves and relaunched in the Carribean after a hurricane.

My personal experience and observations are that whilst steel may require work and attention to retain it's hull integrity, providing this is done there is no practicable safer material from which to build a boat.

[med]

This aluminium boat caught fire or rather melted due to a fire in it while being built. It was written off and construction restarted on a new one to replace it.

The Fire by Alan Wagner | Photobucket

[estarzinger]

Originally Posted by RaymondR

one FG boat burn up at sea,

Just FYI . . . . steel boats can and do burn to a 'total loss'. The steel itself of course (usually) does not burn but it is only a very small fraction of the total value of the boat. Often they sink in the process . . . when for instance the rubber/plastic hoses burn, and the UHMW stuffing box, rudder bearings, or rubber lip seals melt. The propane tanks can blow up in the process, blowing the stern apart.

I'm not at all 'against' steel boats. But they have vulnerabilities just like all other materials.

[FamilyVan]

I'm a bit surprised that aluminum is held in such high regards by forum members. I've spent lots of time on commercialised aluminum yachts, cat and mono. Some were very nice, all would break your back in any kind of sea because they're so stiff and some were real pieces of junk.

Old aluminum welds that have been subject to years of hard use are scary. I've just seen way too many crack and let go when they shouldn't have. Structural stuff too, columns cracking and becoming dislodged, skin separating from frames. To make it worse, they are a pain to repair, not just anyone can weld aluminum.

I'm not saying aluminum doesn't have some great building attributes because it does. But I don't like it that much and I certainly wouldn't be willing to pay the extra bucks for it.

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