And the safest hull material is...

[Doug4bass]

Ferro?


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[GrahamHO]

Originally Posted by MarinerJo

Shouldn't it be a multi hull made of steel???

Yes and with foils.

[PappysSailing]

MStrebe,
You have brought all of us some interesting raw/hard data to sort out. Thank you for the work you put into that project. Cheers, Pappy

[savoir]

Originally Posted by Ann T. Cate

There are a whole lot of aluminum runabouts. Fishermen go missing from them often. Perhaps that skews the aluminum statistics.

To evaluate that data, it would help to know more about the types of boats involved.

Ann

That's because they flip. Nothing to do with hull integrity.

[thinwater]

Originally Posted by savoir

That's because they flip. Nothing to do with hull integrity.

Bingo.

The truth is that we would need to look only at sinkings due to hull failure (not a through hull, not capsize, not a packing failure, not dismasting, not windows stove in, not flooding through the companionway...), and then we have to control for similar designs.

Then we have to decide what we think about sinkings due to poor maintenance on wood or steel. Even a well-maintained vessel can have a bad seem overlooked.

I'm pretty sure you are not going to find enough data on pure hull failure of similar vessels in similar circumstances to look at stats, only anecdotes.

And the open discussion of 1/4" steel plate is pretty funny. MUCH heavier than the materials it was compared to.

[Manos1955]

Originally Posted by Ann T. Cate

There are a whole lot of aluminum runabouts. Fishermen go missing from them often. Perhaps that skews the aluminum statistics.

To evaluate that data, it would help to know more about the types of boats involved.

Ann

the way he presents the data is like all fatalities or injuries caused because of hull construction however many fatalities caused from simple capsize

[builder dan]

Its hard to fight facts steel is awesome

[RaymondR]

Originally Posted by GrahamHO

Battleships are usually steel. There were some aluminum (frigates I think) battleships in the Falkland War. The aluminum caught fire and burned like magnesium when hit by Exocet missiles.

So my next battleship will definitely be steel. Maybe an aircraft carrier to be really safe.

The aluminium did not catch fire so much as just slumped into balls of molten metal because of it's low melting point. However aluminium can be quiet flameable and is used in rocket fuel.

I came to have a steel boat by way of my wife having read a number of survival stories I had in a file whilst I was trying to decide which material to build in. She glanced through the file and said " Every boat which survived being run down, crushed, beached and burnt was steel so I will go cruising with you if you build a steel boat" end of decision process.

[jheldatksuedu]

If I were going to design a boat, It would have a steel hull and have a fiberglass topsides with steel supporting structure under it. Most of my rebuilding my steel boat has gone into fixing severely corroded (rusted through) spots on the topsides around the ports, companionways, dorades, etc. The topside steel is thin and doesn't last, (45 year old boat). Little punch through strength is needed topsides, but structure is needed to maintain hull shape. I would make sure the fiberglass covers the entire topsides and drains into the sea, never allowing water from the topside to touch any of the steel. The hull is rather easy to repair and replace sections if needed, thick steel is much easier to weld. I replaced rusted hull sections in a couple weeks, and have spent years on fixing all the topside rust problems. Much of it has been replacing small portions of thin rusted steel with fiberglass. Fiberglass is easy to work with to make repairs and modifications and rather maintenance free. I have been a welder all my life and taught engineering. I taught a class on composite materials (fiberglass) design and construction. I was involved in building the first all fiberglass highway bridge. Other problems I have fixed involve bilge access, and rotting wood, my beautiful teak interior on my million dollar yacht is attached to pine that is attached to the steel. The company executive that made the decision to use pine should be keel hauled. Maybe I should thank them, by making the bilge not accessible for maintenance, it rusted through and I was able to buy my boat for $5K with a brand new $15k engine in it.

[Factor]

Lies
Damned Lies
Statistics.

Ones that don't sink might be a start

[valhalla360]

Originally Posted by jheldatksuedu

No question, steel. Small steel boats (less than 100 ft) are much stronger in impact resistance than anything of reasonable cost and normal construction. Take a piece of steel 1/4 inch plate, 3/8 inch fiberglass, 3/8 inch aluminum plate, 1 inch thick wood and attack them with an axe or sledge. The steel will be bent to heck, but still one piece, and it will last much longer than you will swinging the axe or sledge. The aluminum will easily cut with the axe and fatigue with the sledge and break. The fiberglass might survive one blow of either but not much more than one. A small steel boat is the only thing that might survive a collision with a semi submerged container or an iceberg. Small steel boats are typically much thicker than they have to be for strength, they have to be able to have some extra material for corrosion resistance. The bottom of my keel is 1 inch thick plate, the sides 3/8, it could pound on a reef or rocky shore much longer than any other construction. A container collision a full speed in fiberglass, aluminum, or wood boat, if it didn't have sealed compartments, I don't think you would even have time to get your ditch bag out of a locker, there would be a 4 foot hole and the boat would be under in a minute or less. Steel would most likely have a huge dent but probably still be watertight. I did have a 27 foot steel boat for a small time. I think it could probably survive being dashed onto a rocky shore by 50 foot breaking wave.

If you are interested in heavily built boats, fiberglass would be upwards of 1-2" thick below the waterline to compare (our old powerboat which was not "blue water" had fiberglass that thick). 3/8" would be a relatively light built. Also as the years go on, the fiberglass doesn't rust away.

Now if you are going to regularly running it up onto the rocks, steel is probably better but for normal usage, a good fiberglass hull is not statistically more likely to fail.

Likewise, it depends on the build quality of the steel boat. A poor quality weld could easily split the first time it hits the rocks.

Each material has it's pros and cons. As you get ever larger, steel makes more sense as it's relative strength becomes more of a benefit relative to it's weight.

[44'cruisingcat]

Originally Posted by ski69sail

(.Steel is Real )

Glass is class
Wood is good
Aluminium is .... ah....

[thinwater]

Originally Posted by builder dan

Its hard to fight facts steel is awesome

Yup heavy rusts cold hot

A clear case of horses for courses, I think.

[micah719]

Ferrous Composite Flubbersteel. An amazing material! Proven safety record since, because it doesn't actually exist, cannot burn, sink, or be stolen. I was considering starting a Gofundme campaign to fleece attract gullible daring investors. I'll use the profits to build with...heheh.....guess.....

[jheldatksuedu]

Originally Posted by thinwater

Bingo.



And the open discussion of 1/4" steel plate is pretty funny. MUCH heavier than the materials it was compared to.

Much heavier, but typically used in the construction, the weight of the material to make a hull has little bearing on the overall weight of the vessel. Remember we fill a wood/aluminum/fiberglass and steel hull with lead to make it stable.