Thinking of buying a Steel boat - what to consider?

[GHB]

Would a steel hull stand up to a high powered rifle shot?

Yes. Though not sure of the rifle, met a guy in Trini with quite a small steel boat with bullet dents in the cockpit coaming from some Venezuelans wanting to redistribute a bit of wealth.
Same boat ended up well away from the water in a hurricane so he did some welding & popped a few dents then went sailing again.

 

[geem]

Very few GRP boats are built with a layup which is thick enough to have the same weight per square metre as a steel boat.
I.e. they are built to be lighter.

So the comparison is much harder than looking what got broken after a hurricane. Almost all of those GRP boats will have been built to be lighter than a steel boat of the same size.

Would a steel hull stand up to a high powered rifle shot?
Mercedes Guardian cars will stand up to a high powered rifle shot. And what are they reinforced with? Carbon fibre and GRP!

I am not talking about theory. I am talking about reality. I explained what happens in practise based on what I saw. Steel boats are what they are. If they are built from thicker steel that maybe because their intending use was ice. Why build a steel boat and have the hull as fragile as GRP. You have no advantage. You may as well have chosen GRP.
I am sure the GRP boat builders didn't consider bullet proof as part of the build spec when they laid up the hull. Quite a different construction to a bullet proof vest or car armour

 

[GHB]

I am not talking about theory. I am talking about reality. I explained what happens in practise based on what I saw. Steel boats are what they are. If they are built from thicker steel that maybe because their intending use was ice. Why build a steel boat and have the hull as fragile as GRP. You have no advantage. You may as well have chosen GRP.
I am sure the GRP boat builders didn't consider bullet proof as part of the build spec when they laid up the hull. Quite a different construction to a bullet proof vest or car armour

afaik hull thickness can be quite thin in steel but they go a bit thicker to allow for wastage due shoddy maintenance

 

[AndrewB]

Would a steel hull stand up to a high powered rifle shot?
Mercedes Guardian cars will stand up to a high powered rifle shot. And what are they reinforced with? Carbon fibre and GRP!

Moitessier claimed that the 6mm steel plate used in the construction of "Joshua" would withstand automatic gunfire at short range. I think he meant an AK47, a favoured weapon of pirates in his day. A bit heavy though for a Mercedes!

 

[westernman]

Moitessier claimed that the 6mm steel plate used in the construction of "Joshua" would withstand automatic gunfire at short range. I think he meant an AK47, a favoured weapon of pirates in his day. A bit heavy though for a Mercedes!

Mercedes-Benz's armored S-Class can withstand AK-47 bullets

 

[Wansworth]

Cautionary tale….an friend had built a large eventide about 33feet it was built by a firm in the Midlands.Anyway having fitted it out for world cruising it was launched and floated well below its marks and the cockpit floor was awash.My friend knew little about boats and I suspect he overspecked the plating thickness or was offered a good deal on thicker plate.The friend was very non committal .Itwasa very cranky boat I am afraid onthe sea trial we did,very tippy.Anyway he sailed off and not heard since,that was 30years ago.

 

[AndrewB]

Cautionary tale….an friend had built a large eventide about 33feet it was built by a firm in the Midlands.Anyway having fitted it out for world cruising it was launched and floated well below its marks and the cockpit floor was awash.My friend knew little about boats and I suspect he overspecked the plating thickness or was offered a good deal on thicker plate.The friend was very non committal .Itwasa very cranky boat I am afraid onthe sea trial we did,very tippy.Anyway he sailed off and not heard since,that was 30years ago.

That is a problem with steel boats - the design may be sound, but then the owner 'adapts' it during construction. The most common mistake is to add head-room, because a steel yacht under 40' won't have enough. Raising the COG results in a tippy yacht. This can be, as you suggest, very uncomfortable if not virtually unsailable in an open ocean swell. Having discovered this, the would-be blue-water owner then quietly disposes of it and returns disillusioned with no further interest in sailing. Perhaps that's what happened to your friend.

 

[RunAgroundHard]

Yes, steel can be deformed past its elastic limit, without yielding. GRP doesn't do this. ....

No it can't by definition. If it deforms past its "elastic limit" then it has yielded, that is the very definition of yield point. Yield strength is the maximum stress that can be applied before permanent deformation, which is the "Elastic Limit" i.e. before this limit is reached, the steal will not deform permanently. Tensile strength is the point at which it breaks. It would be correct to say that steel can be yielded before tensile failure. However, yielded steel is not a place to be on a boats hull because the steel will work harden and be more brittle, therefore less resistant to further deformation i.e. further small movements will cause tensile failure, the forces required to deform, may have stressed other areas of the hull beyond their elastic limit, which is not noticeable. GRP has the same response but at different stress and dimensions than steel.

It is pretty obvious that steel is a suitable material for yachts, as is GRP, but GRP is more forgiving in general use and is better suited to the foible human being. It is also more productive to plan on avoiding the situations where steel's properties may be more survivable.

 

[Wansworth]

Looking back If I was going to do it again I would consider a steel hull married to a wood deck and cabin sides ,maybe with bulwarks with deck low to the water.With wooden deck bless maintenance easier to fix stuff less painting on deck and lighter

 

[geem]

Looking back If I was going to do it again I would consider a steel hull married to a wood deck and cabin sides ,maybe with bulwarks with deck low to the water.With wooden deck bless maintenance easier to fix stuff less painting on deck and lighter

Surely the joint of the steel hull and a wooden deck is its failure point. Steel in contact with wood loves to rot

 

[Wansworth]

Surely the joint of the steel hull and a wooden deck is its failure point. Steel in contact with wood loves to rot

Yes,needs thinking about

 

[Bouba]

Let’s face it, boats are made from GRP because they can be made into exotic shapes and be mass produced

 

[Wansworth]

Let’s face it, boats are made from GRP because they can be made into exotic shapes and be mass produced

And don’t need maintenance ?

 

[Tranona]

Looking back If I was going to do it again I would consider a steel hull married to a wood deck and cabin sides ,maybe with bulwarks with deck low to the water.With wooden deck bless maintenance easier to fix stuff less painting on deck and lighter

Much more common in commercial vessels and some steel hulled superyachts to have aluminium superstructures.

 

[NormanS]

Steel boats can be built one off, by an appropriately skilled person, relatively cheaply. GRP requires sophisticated and expensive moulds, and is more suitable for mass production.
Some years ago, I built an Alan Pape designed 33' multi chine steel yacht. I completed all the steelwork, hull, deck, ballast keel, coachroof, cockpit etc. My circumstances changed, and there was a pause, someone made me a good offer for the boat, so I didn't complete the fitting out, and never sailed her.
At the time of building, I had a big (60') carvel built elderly wooden boat, so the idea of a sprung plank, was always somewhere in my mind. The steel boat had no such worries.
I now have an excellent GRP yacht, and would now never go back to either wood or steel.

 

[Wansworth]

Steel boats can be built one off, by an appropriately skilled person, relatively cheaply. GRP requires sophisticated and expensive moulds, and is more suitable for mass production.
Some years ago, I built an Alan Pape designed 33' multi chine steel yacht. I completed all the steelwork, hull, deck, ballast keel, coachroof, cockpit etc. My circumstances changed, and there was a pause, someone made me a good offer for the boat, so I didn't complete the fitting out, and never sailed her.
At the time of building, I had a big (60') carvel built elderly wooden boat, so the idea of a sprung plank, was always somewhere in my mind. The steel boat had no such worries.
I now have an excellent GRP yacht, and would now never go back to either wood or steel.

Ebbtide

 

[Wansworth]

Much more common in commercial vessels and some steel hulled superyachts to have aluminium superstructures.

Or grp?

 

[NormanS]

Ebbtide

No, it was a Steelmaid, or Steelmaiden . It may have been 34'. It's a long time ago, and my memory isn't what it was.

 

[westernman]

Steel boats can be built one off, by an appropriately skilled person, relatively cheaply. GRP requires sophisticated and expensive moulds, and is more suitable for mass production.
Some years ago, I built an Alan Pape designed 33' multi chine steel yacht. I completed all the steelwork, hull, deck, ballast keel, coachroof, cockpit etc. My circumstances changed, and there was a pause, someone made me a good offer for the boat, so I didn't complete the fitting out, and never sailed her.
At the time of building, I had a big (60') carvel built elderly wooden boat, so the idea of a sprung plank, was always somewhere in my mind. The steel boat had no such worries.
I now have an excellent GRP yacht, and would now never go back to either wood or steel.

GRP boats can be built one off by an amateur as well. No expensive moulds are needed. For instance with C-Flex fibreglass planks (other methods are available as well).
For instance:-
C-Flex

 

[Bouba]

GRP boats can be built one off by an amateur as well. No expensive moulds are needed. For instance with C-Flex fibreglass planks (other methods are available as well).
For instance:-
C-Flex

Very clever stuff...I’m not impressed with the guy holding a plank without gloves