minimum size steel?

[zeljkomrsic]

I'am new on the forum. Sorry on my bad English grammar-Thanks!

What is the smallest size of steel boat what we can built (houseboat)?

I hope you understand me!:)

[marshmat]

Steel construction doesn't really have a lower size limit.... well, it does, but it's pretty darn tiny. You could build a 4-millimetre boat out of steel if you wanted to.
What's the intended use of the boat? How many crew, what kind of sea and wind conditions?

[zeljkomrsic]

Hmm, yes you are right.
I want to make small boat from 5 to 7 meter (about 20 foot) for the first time? I live in Croatia, we have many island and many bays, the sea and wind is silent.
May I make boat of this size? What is the thickness of hull (steel)? We have many boats in our town but I didn't find steel boat this size. I find aluminium small boats but I want steel?

Thanks!

[martinjancar]

I have a steel boat of type Wibo 740. It is located in Pula. If you wish more information, just send an e-mail on martinjancar@yahoo.com.

[marshmat]

Zel- the simple answer is yes; how heavy you make the plating depends on how the structure is set up and how much abuse it will have to take. Will it be used as a workboat, or just for fishing from.... will it be hauled out on rocks..... how much speed/power do you need.... Take a good hard look at how you'll use the boat, and with whom, before you commit to anything.

[zeljkomrsic]

Mars_ Thanks you!
I find some information, Martinjancar help me lots. I don't decide yet what technic to use. Martin have boat Wibo 740 7 meter, loks verry good.

Thanks you again and sorry on my bad English grammar!:)

[Wynand N]

Steel construction doesn't really have a lower size limit.... well, it does, but it's pretty darn tiny. You could build a 4-millimetre boat out of steel if you wanted to.
What's the intended use of the boat? How many crew, what kind of sea and wind conditions?

4mm plate actually builds large boats....
The Dix 65 (Lorrigray featured in Dix's webpage) I built was with 4mm plate on entire hull sans keel and 3mm on deck.
Incidently, the Dix 57, Dix 38 (frameless) v/d Stads 34 / 40's were built of the same combination ; 4mm hull & 3mm deck

I also built a few Tom Thumb 24's (Grahaeme Shannon designed) frameless method, 3mm plate on hull, keel and deck and they were extremely strong - one even done a circumnavigation.

OTOH, I designed a little pocket 23ft steel cruiser similar to TT24 with a very light but strong frame, plated with 2.5mm hull and 1.6mm deck plating. To make it last is a question of an extremely carefull applied epoxy paint system

[zeljkomrsic]

Wynand,
Do you have picture of 23ft steel cruiser similar to TT24?
Do you make frame with 2,5mm?
How you weld steel 2,5mm, with electrode or gass?

Thanks!

[Wynand N]

Zel,

Unfortunately the design was done on AO sized plan paper and I must get it redused for posting and do not have the facilities closeby to do it now.
But I include a picture of my Tom Thumb 24 under construction many moons ago and she have since done a circumnavigation with her current owner.

My design looks 90% like her but the main difference is that it is raduised chine whereas the TT24 is multichined.

No, the framing is 40 x 6m transverse frames with 25 x 5mm longitudinal stringers and the keel area have 4mm transverse reinforcing/floors.

Do not bring a gas welding unit near steel!! It will overheat and distort the plates as it is a very slow process.
Rather use arc (electrode) welding although I personally prefer the Mig Co2 welding process.

[Richard Hillsid]

I also built a few Tom Thumb 24's
THIS one is good bought the drawings, made model but never built it.

[zeljkomrsic]

Thanks Wynand,
verry kind from you