On Tue, 21 Aug 2007 18:30:09 -0500, "KLC Lewis"
wrote:


"Richard Casady" wrote in message
.. .
On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long"
wrote:

Strong as wood, heavy as steel, about sums it up.

My inland lake fishing boat is 22 feet of riveted aluminum. It has a
bow locker with two tiny bunks. Too thin to weld. It is both strong
and light and I love it. It cost two grand, and if the available steal
had been glass, I would have that. Steel is either too thin for good
welding, or too heavy, in anything smaller than maybe seventy five
feet. You can perhaps rivet that stuff too. Aluminum killed the wood
boats before there even was glass. Where I do my boating there are a
bunch of aluminum boats mostly fifty years old, no maintainence ever,
and lighter than the wood they replaced. Aluminum is good, but it is a
bit noisy in the sheet metal type thicknesses. Of course, destroyer
hulls were famous for noisy oil canning. Why they called them tin
cans. Quarter inch plates.

What is this repeated comment about "steel...too thin for good welding"?
Unless we're talking about foil, thinner gauge steel (16 or even 18 ga) is
entirely weldable. I should think 1/4" steel would be excellent for
below-the-waterline on a 35 footer, perhaps going to 1/8th or 3/16ths above
the waterline and for decks. Frames could be trussed to achieve strength
without excessive weight. I believe that the biggest reason for having
extreme thickness in steel hulls is to provide more material that can be
lost to corrosion before compromising the hull. But with modern epoxy
coatings, perhaps overlaid with glass or some other material for abrasion
protection (to protect the epoxy barrier), this could be made unnecessary.

Just thinking aloud.

What he is talking about is that the wrinkled steel hulls that you see
are generally pretty thin. But the wrinkles are generally a factor of
economics. If you want to pay for the experience and the time there is
no reason that a welded metal boat can't be pretty damned fair. But it
is going to cost you so much money that it won't seem worth it. Much
cheaper to slap on the filler and sandpaper it.



Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long"
wrote:

They are heavy for their length though and you'll probably find that
you can carry a lot more sail then the fiberglass boats.

But a LOT less than a cored glass boat of the same shape and equal
displacement with the weight saved in the hull carried as ballast. The
glass boat will also be much stronger if some of the weight savings is used
to add material.

Give the ferro a break and compare it to cheaper solid glass, and it
still comes off second best. How is cored for home building? I like
riveted aluminum myself, and it is easy to work with. They use it for
airplanes. Some are home built. Nice thing about it is, you can drill
out rivets, replace mangled metal, and have it exactly like it was.
How do you repair ferro after say, a collision. Can you say shipping
container. Those weigh almost forty tons when awash.

Casady

On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long"
wrote:

They are heavy for their length though and you'll probably find that
you can carry a lot more sail then the fiberglass boats.

But a LOT less than a cored glass boat of the same shape and equal
displacement with the weight saved in the hull carried as ballast. The
glass boat will also be much stronger if some of the weight savings is used
to add material.

Give the ferro a break and compare it to cheaper solid glass, and it
still comes off second best. How is cored for home building? I like
riveted aluminum myself, and it is easy to work with. They use it for
airplanes. Some are home built. Nice thing about it is, you can drill
out rivets, replace mangled metal, and have it exactly like it was.
How do you repair ferro after say, a collision. Can you say shipping
container. Those weigh almost forty tons when awash.

Casady

On Aug 24, 10:33 am, (Richard Casady)
wrote:
... How is cored for home building? ...

Very good. For one offs it is about as cheap to build cored hulls as
solid glass on male tooling and cheaper than solid glass on female
tooling. There are many strip-plank methods that involve laying
strips of core over bulkheads (typically produced with a flat panel
cutter) and then glassing. These methods eliminate lofting and
greatly reduce tooling. Done well they do require a lot (really huge
amounts of back breaking horrible work) of fairing after the planking
stage otherwise they will need to be heavily bogged to get them as
fair as traditional female tooled boats. There are other methods like
(http://www.kelsall.com/methods.html which I've seen used with
impressive results) that can cut down on fairing. Of course, the job
really starts once you've turned the hull over. Fit-out costs are
pretty much unrelated to the hull construction method and for a
typical cruising boat the great majority of the work and cost is fit
out. The hull may only represent 20% of the completed cost of a
nicely fitted yacht.

-- Tom.

On Fri, 24 Aug 2007 20:32:24 GMT, (Richard
Casady) wrote:

On Fri, 17 Aug 2007 08:52:17 -0400, "Roger Long"
wrote:

They are heavy for their length though and you'll probably find that
you can carry a lot more sail then the fiberglass boats.

But a LOT less than a cored glass boat of the same shape and equal
displacement with the weight saved in the hull carried as ballast. The
glass boat will also be much stronger if some of the weight savings is used
to add material.

Give the ferro a break and compare it to cheaper solid glass, and it
still comes off second best. How is cored for home building? I like
riveted aluminum myself, and it is easy to work with. They use it for
airplanes. Some are home built. Nice thing about it is, you can drill
out rivets, replace mangled metal, and have it exactly like it was.
How do you repair ferro after say, a collision. Can you say shipping
container. Those weigh almost forty tons when awash.

Casady


Actually they make some sort of almost instant curing "cement"
originally designed to fix leaks in water tanks. The "Fero" boys all
carry that and according to a mate who sailed into a rock at about 7 K
it works real well in fixing holes in fero boats.

The whole point to fero boats was that they are cheap to build.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)

On Sat, 25 Aug 2007 09:34:34 +0700, wrote:

How do you repair ferro after say, a collision. Can you say shipping
container. Those weigh almost forty tons when awash.

Actually they make some sort of almost instant curing "cement"
originally designed to fix leaks in water tanks. The "Fero" boys all
carry that and according to a mate who sailed into a rock at about 7 K
it works real well in fixing holes in fero boats.

The whole point to fero boats was that they are cheap to build.

Good point.

I will check out that quick curing cement, my curiosity is aroused.

As others have pointed out, the hull is a relatively small part of
the cost of the finished boat. On a slightly related note, as people
like to say about building a warship with room for growth in equipment
fit: " Steel is cheap. and air is free "

Casady

On Sat, 25 Aug 2007 16:00:32 GMT, (Richard
Casady) wrote:

On Sat, 25 Aug 2007 09:34:34 +0700, wrote:

How do you repair ferro after say, a collision. Can you say shipping
container. Those weigh almost forty tons when awash.

Actually they make some sort of almost instant curing "cement"
originally designed to fix leaks in water tanks. The "Fero" boys all
carry that and according to a mate who sailed into a rock at about 7 K
it works real well in fixing holes in fero boats.

The whole point to fero boats was that they are cheap to build.

Good point.

I will check out that quick curing cement, my curiosity is aroused.

Home Pro here sells several brands. But do read the instructions and
where it says, "you have 60 seconds working tim," believe! It is fast.

As others have pointed out, the hull is a relatively small part of
the cost of the finished boat. On a slightly related note, as people
like to say about building a warship with room for growth in equipment
fit: " Steel is cheap. and air is free "

Casady

That is true but not what people who are building a dream want to hear
or believe and most of the ferro boats were built by that kind of
people.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)