Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 25-11-2011, 18:51   #31
Registered User
 
leftbrainstuff's Avatar

Join Date: May 2011
Location: San Francisco and Australia
Boat: Liberty 458
Posts: 1,978
Stainless steel is not a viable choice for a yacht hull. As another respondent mentioned stainless steel can corrode quicker than mild steel in certain situations. Specificall crevice corrosion with pitting rates of mm / week. The weld joins and penetrations would be an issue. Other hi alloy materials such as the nickel based superalloys are cost prohibitive.

To build a ss yacht i would look into explosive forming and 100% weld inspection. The mold for the forming would likely cost more than the yacht. Xray quality welds would also consume a big expense for consumables and inspection.

The high manganese steels used to build containers and ship hulls is a cheaper, readily weldable and suitably corrosion resistant option.

Also any repairs to your ss yacht would seriously degrade the integrity of the hull. Fatigue being the main issue.
__________________

__________________
leftbrainstuff is offline   Reply With Quote
Old 25-11-2011, 18:51   #32
Registered User
 
Tristan's Avatar

Join Date: Aug 2006
Location: Cruising
Boat: Custom Ketch Asperida
Posts: 211
Re: Stainless Steel Yacht ?

Yeah !
Asperida is my boat. Still alive and still floating.
According to my calculation there is still around 500 years to go. (Cannot sleep at night because of that.)
T.
__________________

__________________
Tristan is offline   Reply With Quote
Old 25-11-2011, 19:16   #33
Registered User
 
Ctrich's Avatar

Join Date: Sep 2005
Location: Vancouver, Canada
Boat: custom 65 steel
Posts: 20
Images: 3
Re: Stainless Steel Yacht ?

COMPARISON WITH CARBON STEELS
The fatigue strength of austenitic and duplex stainless steels are compared with those of high
strength ferritic-martensitic carbon steels, DP steel, at the same yield strength levels.
500
450
200
304
301
250
300
350
400
150
100
50
0
Rp=270 Mpa
Rp=450 Mpa
Rp=600 Mpa
Figure. 14. Comparison of fatigue properties between stainless and carbon steels at different
yield strength levels.
The result of this comparison is given in fig. 14. On all strength levels studied the stainless
steel showed better, and often substantially better, fatigue properties than corresponding
carbon steel.
www.outokumpu.com/files/Group/HR/Documents/​Fatigueproperties.pdf
Mmmm.... the graph did not copy.
A shiny stainless sailboat, I think her name will be Bling,
Tristan, do have a SS boat?
__________________
Ctrich is offline   Reply With Quote
Old 25-11-2011, 19:30   #34
Registered User
 
Tristan's Avatar

Join Date: Aug 2006
Location: Cruising
Boat: Custom Ketch Asperida
Posts: 211
Re: Stainless Steel Yacht ?

Quote:
Originally Posted by Ctrich View Post
COMPARISON WITH CARBON STEELS

Tristan, do have a SS boat?
No, Asperida is 70/30 copper-nickel
T.
__________________
Tristan is offline   Reply With Quote
Old 25-11-2011, 19:31   #35
Registered User
 
Ctrich's Avatar

Join Date: Sep 2005
Location: Vancouver, Canada
Boat: custom 65 steel
Posts: 20
Images: 3
Re: Stainless Steel Yacht ?

Is a stainless steel boat possible? - Boat Design Forums
__________________
Ctrich is offline   Reply With Quote
Old 25-11-2011, 19:38   #36
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
That report is very positive about cupro nickel. A metal boat always looses plate thickness over years and this is a '60s built boat ! Also, it really seems to be the ultimate anti fouling hull.

About the Monel hull that fell apart... It was the steel structure that the monel plates were welded to that failed. Never mix different metals that way; same would happen with aluminium on steel etc.

Cupro-nickel still sounds like a winner to me :-)

ciao!
Nick.
__________________
s/v Jedi is offline   Reply With Quote
Old 25-11-2011, 20:00   #37
Registered User
 
Ctrich's Avatar

Join Date: Sep 2005
Location: Vancouver, Canada
Boat: custom 65 steel
Posts: 20
Images: 3
Re: Stainless Steel Yacht ?

BIG YACHT NOW JUNK AFTER 6 WEEKS' USE - Sea Call's Monel Metal-Steel Hull Ruined by Electrolysis, Builders Admit. COSTLY EXPERIMENT FAILS Action of Sea Water Attributed by Metal Makers to Failure to Use Zinc Insulation. - Front Page - NYTimes.com

Big yacht junk after 6 weeks.... published in the NY times in 1915
__________________
Ctrich is offline   Reply With Quote
Old 25-11-2011, 20:08   #38
Registered User
 
Ctrich's Avatar

Join Date: Sep 2005
Location: Vancouver, Canada
Boat: custom 65 steel
Posts: 20
Images: 3
Re: Stainless Steel Yacht ?

Triatan, well done ! Was the welding of the 70/30 difficult to learn? The artical mentioned trapped gas in a few of the welds, did you use MIG and what gas was used?
Just curios
__________________
Ctrich is offline   Reply With Quote
Old 25-11-2011, 20:16   #39
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Please read the report, not just the sensational headline. The monel is okay, the steel is okay, but don't weld the two materials into a hull and think they won't start electrolysis. They should have done the experiment in a lab instead.

ciao!
Nick.
__________________
s/v Jedi is offline   Reply With Quote
Old 25-11-2011, 20:25   #40
Registered User
 
Tristan's Avatar

Join Date: Aug 2006
Location: Cruising
Boat: Custom Ketch Asperida
Posts: 211
Re: Stainless Steel Yacht ?

Quote:
Originally Posted by Ctrich View Post
Triatan, well done ! Was the welding of the 70/30 difficult to learn? The artical mentioned trapped gas in a few of the welds, did you use MIG and what gas was used?
Just curios
I used MIG / argon with 70/30 copper-nickel wire and yes, it was difficult because deep oxide formation on the surface. I tried to minimize grinding and tried to avoid chemical cleaning. Unfortunately some of the internal structural elements were made of carbon steel and those were really corroded. I replaced them with 304 SS and in this case I used 30/70 (monel) wire to weld it to the copper-nickel.
T.
__________________
Tristan is offline   Reply With Quote
Old 25-11-2011, 20:35   #41
Moderator
 
Boracay's Avatar

Cruisers Forum Supporter

Join Date: Feb 2004
Location: Pelican Bay, Great Sandy National Park
Boat: Steel Roberts Offshore 44
Posts: 5,175
Images: 18
World's biggest cathode...

The problem as I see it is that with a large amount of stainless below the waterline there's going to be a big difference between the anodes and the hull on the galvanic scale. The anodes may vanish quick smart, followed by the rest of the underwater parts in ascending galvanic order.

It's not a problem on a regular steel boat as there is only a small amount of stainless used and the anodes protect the rest of the steel from it.

But why not use regular mild steel for the hull, and stainless everywhere else.
It would be great for the deck as no worries re corrosion.

Anchor protector, rub rail, all those corners that chip on the stern - they would all benefit from having stainless covers welded on top. Toe rail inward could all be stainless.

The cost would not be huge, and since working with thin stainless sheet and tube would become second nature it may end up a quicker way to build a steel cruising yacht.

Only problem that I can see would be the "bling" factor. Would need sunglasses or some serious abrasive blasting to take the shine off, and some would need to be painted.
__________________
Rust never sleeps
Boracay Blog.
Boracay is offline   Reply With Quote
Old 25-11-2011, 20:40   #42
CF Adviser

Cruisers Forum Supporter

Join Date: Aug 2009
Boat: Custom Van De Stadt 47 Samoa
Posts: 3,744
Re: Stainless Steel Yacht ?

Quote:
Originally Posted by leftbrainstuff View Post
Stainless steel is not a viable choice for a yacht hull.
Really!

You will have to tell that to the three people we know with quite excellent SS boats!

It has pros and cons, like all materials, but you CAN certainly build a very high quality, durable and long lasting hull with SS.
__________________
estarzinger is offline   Reply With Quote
Old 26-11-2011, 07:31   #43
Registered User
 
Ctrich's Avatar

Join Date: Sep 2005
Location: Vancouver, Canada
Boat: custom 65 steel
Posts: 20
Images: 3
Re: Stainless Steel Yacht ?

Boracay has a point, a prop shaft has a lot of zinc for the surface area. On tuesdays child there is about 60 lbs of zinc anodes and the steel is heavily coated in epoxy. How much zinc would it take to protect a 50ft SS boat and how long would the anodes last (cost maintenance). But then the batts and alternator are usually grounded to the engine which grounds to the sea water through the shaft? Mmmmm..........
Estarzinger, if you are in contact with the people with SS boats could you ask them for a short list of pro's and con's.?
__________________
Ctrich is offline   Reply With Quote
Old 26-11-2011, 08:06   #44
Registered User
 
Ctrich's Avatar

Join Date: Sep 2005
Location: Vancouver, Canada
Boat: custom 65 steel
Posts: 20
Images: 3
Re: Stainless Steel Yacht ?

Estarzinger, great web site. been thinking of a static test for righting moments for the boat. Your calculator will make it easy, thanx.
Down loaded your hull structure for ice formula, hope I never have to use it.!
__________________
Ctrich is offline   Reply With Quote
Old 26-11-2011, 08:18   #45
CF Adviser

Cruisers Forum Supporter

Join Date: Aug 2009
Boat: Custom Van De Stadt 47 Samoa
Posts: 3,744
Re: Stainless Steel Yacht ?

Quote:
Originally Posted by Ctrich View Post
Estarzinger, if you are in contact with the people with SS boats could you ask them for a short list of pro's and con's.?
very short list . . .

vs aluminum:
-Heavier than aluminum, but harder (less scratching/gouging).
-Looks nicer than aluminum when unpainted - both holds paint about equally poorly.
-Welding about the same difficulty as aluminum.
-Can use bronze seacocks and copper antifouling paint which are problematic for aluminum.
-Both have about equal potential underwater problems (aluminum:electrolysis vs SSitting/crevice corrosion) both manageable with proper construction

vs mild steel:
- no rust (and reduced cost of painting) vs harder welding and more crevice corrosion problem
__________________

__________________
estarzinger is offline   Reply With Quote
Reply

Tags
yacht

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Steering Cables - Steel or Stainless Steel ? sailorchic34 Construction, Maintenance & Refit 46 14-01-2014 17:46
Rocna Recall - China vs Canada Quality Comparison Hogan Anchoring & Mooring 201 15-12-2011 08:53
For Sale: Scuba Dive Compressor - Compact / Portable / Stainless Steel capnbob5698 Classifieds Archive 4 16-09-2011 19:57
Stainless Steel Ball Valves Celestialsailor Plumbing Systems and Fixtures 15 12-09-2011 21:03



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 03:38.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.