steel V grp hulls

[Rob_karen]

can anyone give us any advice on steel hulls are they a lot of work, what to look for when viewing boats as we have anly owned grp yachts and are interested in the pros and cons of steel versus grp

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[andyball]

There's a lot of info in books/websites out there, ones I read seemed to say that properly prepared/painted steel was no more hassle overall than grp, though of course if an aging grp vs aging steel hull ....the grp'll look/be better for the neglect (no rust spots) & can usually be polished up again....but, I've seen plenty of painted grp boats, so presumably that can be a lot of time & effort.

f you buy a badly repainted steel boat & have to shell out for a proper sand-blast/repaint then doubtless grp wins every time....unless there's loads of blisters; hmmm.

Steel wins easily for hitting things & going aground (but you knew that) relatively easy to repair.

An article in Dec pbo compares steel/grp/aluminium hulls.

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[alec]

From what I have read, the drawback to steel is weight.

Despite what we all may say, none of us like a very slow boat to sail.

Steel seems to make sense over about 45 feet. I have sailed on both steel and ferro of this length and they sailed well. 'Wrong way' Chay Blyth left no doubt as to the strength and sailability when you get the boat 'right'.

Best of luck with your search.

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[MainlySteam]

Re: steel V grp hulls (very long)

Putting aside the weight issue for yachts of up to moderate size, where it is not possible to build a servicable steel vessel any lighter than a heavy frp one, I do not think there is a lot in it as far as maintenance is concerned provided it is a well finished steel vessel. Of course a poorly finished frp vessel will have maintenance problems too.

A low maintenance steel vessel needs to be properly prepared at building for epoxy build coats and linear polyurethane top coats, and to have alot of stainless steel in its structure at points were corrosion is likely to occur such as where lines may rub and in places most do not think of such as ss strips around water tank inspection ports for the cover set screws to be tapped into. All corners should be heavily radiused so that the coating is effective around corners and these should preferably be done with a press rather than by welding sections cut longitudinally from pipe in. The inside of the hull needs the same paint specification as the outside apart from the top coats.

The main difficulties are with chipping of the coating on the decks, which if through to the steel will weep rust and sometimes travel under the surrounding intact coating unless touched up. We use a Dremel every few years to tidy up with a touch of primer, undercoat and top coat - is much easier than a gel coat repair. Our own boat is fully faired top and bottom (although it was built very fair) and this provides some protection from damage right through to the steel from chips - the fairing was done with this in mind so is normally a mm or so minimum thickness. Some boats use timber decks (or teak) and superstructure to avoid some of these problems (and claimed less top hamper), but my personal view is that this is a bad move as they are materials of very different strain performance.

While for deck maintenance for steel one has to be more conciencious than for frp, for hull scrapes, etc from bad docking, etc steel is cheaper to repair the coating of than a gel coat repair. Steel vessels, after a few years usually have small repairs required underwater due to paint failure. These are usually very small flecs where the epoxy releases and the repair is just a simple hit with a small grinder, epoxy and thats it fixed. I have not heard an explanation for this problem but think it is due to water migration through the paint after time resulting in a galvanic reaction with a zinc based primer (if used, some paint manufacturers specify without it now) or between the steel and the copper in the antifouling.

Steel boats are normally structurally very strong, but in areas of cycling forces it pays to have a good check, the main one being in the rudder stock area. Despite their popularity, skegs can be a problem on steel (and other) vessels unless taken through the hull into the internal structure of the vessel (they are commonly just welded to the exterior of the plating). While few steel vessels have spade rudders, if so the stock tube should go through the keelson, which is normally much thicker than the surrounding plate, preferably at a frame and be braced to that frame and the vertical false keel on top of the keelson - apart from some difficulties with plate deformation in the forward slamming areas through inadequate longitudinal spacing, this is the most likely structural trouble spot.

The attachment of the keel does not seem to be much of an issue in practice but unless it is taken up through the bottom of the boat and welded to the internal floors then one needs, in my opinion, to be sure of how it is attached to the hull. If just butted to the hull (our own is, for example) then there needs to be internal floors in the keel which are also continuously welded to the bottom of the boat transfering the load to floors internal to the vessel. This is very hard to check on an existing vessel (the boatbuilder took photos of ours for me for future reference).

My opinion is that plastic thru hulls and seacocks are much preferred in order to avoid corrosion problems. Avoid boats with mild steel piping welded to the underwater hull for salt water services (it rusts out). If plastic, one should ensure that they are of reputable glass reinforced type. For galvanic protection my experience is that people get carried away. Have someone who really knows what they are doing look at the boat - avoid the marina myths which are just that, steel boats are easy to protect and there is no black magic to it. If the prop and shaft are of good materials and insulated from the boat and engine do not protect them. For the hull itself, with plastic fittings, you only need something to protect against minor paint damage. We find that a single smallish anode lasts 2 years easily. You should ensure that the earth of the shore power supply has a galvanic isolator in it or that an isolating transformer is used. You should also ensure that a two wire system (ie the hull is not used as the negative return) is used for DC power, and it is my view that the DC negative should not be connected to the hull (the DC negative bus is often connected to the AC hull ground) - while that is against ABYC the aluminium boats we are associated with going into Class are done as I suggest.

To build a good steel boat is expensive, and will cost at least as much as a timber/glass composite boat if the internal finishes are to be of the same standard, and several times more expensive than a production white boat. While most of my work is with much larger vessels I think custom non-steel 40 foot boats cost around the equivalent of GBP300,000 plus. While the steel hull materials are cheaper the finishing costs are higher, including the need for good insulation and internal hull linings.

In my opinion then to get a good steel boat it would have been expensive in the first place, but not necessarily so second hand. If you can find one of those that matches your needs then go to it. However, even though I own a steel yacht (a professional custom build) my view would be that unless one can find such a boat at an acceptable price on the second hand market, or come across a very good amateur built boat (unlikely) or can stretch to a high quality new build, one is likely to avoid a lot of future heartache by buying a good frp (or even aluminium) boat instead.

John

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by MainlySteam on 16/11/2003 22:44 (server time).</FONT></P>

 

[MainlySteam]

On the subject of weight. It is possible and simple if one knows how, to built a steel vessel 40 foot or over which is the same weight as a typical solidly build frp vessel. For example, our own yacht is approximately the same weight as similar volumed vessels from the quality builders such as HR, Alden, etc.

Obviously, if one wanted a light boat for fast cruising or for racing then one would not choose steel, just as one would not choose heavy frp construction. However, as far as moderate construction weight cruising vessels are concerned a steel vessel need not be slow. I remember one cruise boat day race (I crewed on a beautiful Hinckley) where the only requirement was for the boat to be over 10 tonnes displacement, two well designed steel vessels came in well ahead of the next boat - the fleet included vessels up to approx 55 foot.

Just as with any other boat, its design has alot to do with performance. We spent some time in the same port as Wanderer IV (the Hiscocks old approx 48 foot steel yacht) and while there was never a race we several times found ourselves on similar courses to a destination - our 40 foot fin keeled, spade ruddered yacht outsailed it by far insomuch as speed was concerned.

Again, if one wants a faster boat than most others, steel is not the way to go. However, if that is what one wants then one would have to be careful with your frp choices too.

John

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[oldsaltoz]

Glass boats as a rule are less work but more expensive to repair.

Steel boats can be hot in summer and very cold in winter, they also have more problems with condensation than glass boats.

Glass boats made a few years ago may develop some form/s of osmosis, steel will rust if exposed, even a pin hole is a problem.

When looking at a steel boat make sure you inspect the internal frame, any sign of corrosion here is a major problem, as replacing a frame can mean removing a lot of the hull to gain access.

Heaven is a soft rock if your aboard a glass boat.

Avagoodweekend...

<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.