Is a stainless steel boat possible?

I've used what my friend had in shipyard...no choiche!
The boat was built on 1986...20 years ago...!

 

I would ask the grade of varies type..... 316 seem to be the norm? the special would cost a lot more and still if you have a dream then burning money is still an option

 

316/2205

I replaced the standing rigging on my 26' Superseal (Ron Holland design) in spring 2005. 1x19 s/s 5mm wire

Boat is on a swinging mooring in Portland Harbour , Dorset, England.

By September, there were spiral rusty looking marks on all the rigging.

General opinion, which I cannot confirm, was that this is due too insuficient cleaning of the individual strand after wire drawing.

Does anyone know anything about this?

The rigging supplier 'fixed'? this by cleaning the rigging with something like Scotchbrite.

After hearing that someone else had this problem, I enquired with BSSA (British Stainless Steel Association)

The bombshell in the conversation was when the consultant said that 316 was not realy suitable for a marine environment, but you yachties get away with it because you put up with a short life e.g. ten years. He went on to say if the use was for a suspension bridge, for example, with a design life of 120 years, you would specify 2205, which has higher percentages of alloying components including 6% molybdenum.
316 is 2%

My first experience of s/s corrosion was when the mast on my OK dinghy fell over due to the two 5mm bolts holding the wooden block at the mast foot disintegrating.

S/s of ??? spec in permanently wet wood, kind of condition in previous post.

 

"...burning money...". I have used what my friend had in shipyard, it is not a question of money...but for me a dream has no price...

 

I understand about, I am also involved in a friendship building in my yard (long time already...sik...no time!)

 

S.s. Corrosion

I would suggest that messers; IKE and FRANK MARSDEN are on the
right track.

The main concern to me is......

CREVICE CORROSION !!!

Note: Fine cracks, virtually invisable to the eye - dont easily allow
a free flow of air.
Whereas; according to M.I.T. - the capilary power of water is:
- a MILLION p.s.i. !!
( A sobering fact - for boat designers and sailors to consider.)

Meaning: your SS will corrode. For sure. The only debate is:
- How long will it take.
Adding fuel to the fire ( literally) - like immersing your expensive alloy
in a corrosive electrolyte, simply speeds things up !

SS deck cleats work well. - Because they lack CREVICES.
Also they are supplied generously with oxegen.
( Except when you are sailing well heeled over - with the
rail awash.)

WELDING is a major concern as well. ( Especialy in SS.)
It's logical that: as the alloy is formed with heat
- it follows: that heating it, by welding, will undo the alloy's integrity.
- defeating the whole perpose for using SS, in the first place.

Also: Note CORMERAN's 33rd Law:

" The only good weld - is an X - RAYED weld "

(Now; there's an extra cost - that most backyard builders
will not want to hear about.)

Suffice to say:

Check out the history of the ALASKA PIPELINE - where
they tried to skimp on X - Ray testing - and had to
redo miles and miles - and miles of bad welds. At 40 below!

 

SS used mix-gas for shielding...... the gas also cool the job while preventing the oxygen from contiminate the weld....

WDH

 

it is true that polishing minimizes corrosion??? and so why 304 in deck hardware it is acceptable instead of 316??

 

it is true that polishing minimizes corrosion???

polishing minimizes the parts surface area , therefore less corrosion.

Electro polishing removes free iron in the surface of the SS part by plating something with the iron.

Po Boy polishing is simply using Ospho (a weak mix of Osphoric acid) and a detergent to hold it in place on the surface.

A table spoon of Joy and 2 or 3 of Ospho can be scrubbed on with a scotch brite pad and allowed to dry. Do it a couple of times and the surface iron will be mostly gone.
This leaves rather medocre SS looking fine for a few months , at low cost.

FAST FRED

 

Rust at the welds.

Sandard A4 or 316 SS is non-magnetic. However if you weld pieces together, upon cooling, the weld and surroundinng area microstructure turns into A2 (i.e. magnetic).

I know jack about welding, except how to do a half decent weld, but it would be interesting how you would cool your SS so that it remains A4 especially ove large areas?

 

use 316L and there is much less of a problem...the carbon level is especially low in this alloy.

Steve

 

For a really good understanding of the pro's & con's of building in different metals it's worth reading an article by Michael Kasten www.kastenmarine.com
Somewhere in the site in his articles on boatbuilding with metal is one devoted to this that I would recomend anyone read.

316L stainless is used because the lower carbon level reduces precipitation which in turn reduces the tendency to fatigue. Crevice corrosion is still a problem though.

Fast Fred is right. Monel's better. I personally have been considering using 70/30 copper nickel plate on monel frames for a boat to see me out (I'm in my mid 30's) but the issue is cost.

If it cost's 4 to 6 times more to build a hull to last a lifetime, wouldn't I be better to just build 4 hulls in a lifetime:?: But then I remind myself how much I hate barnacles.

 

4 boat in a life-time is better...... you should often the picture gallery and really a need to build a better boat.

Well as long as the SS doesnt sit in salt water then it is a very good shinny material for deck decoration and ultility.

WDH

 

Up to fairly long waterline lengths, it's hard to be more cost/ effective than
- wood and epoxy.
After all: if God had ment us to make steel boats - would he not have created
- steel trees........ ??

 

Stainless steel must be for the look of it
I can see no other reason.