How thick should the steel or aluminum be.

dlochner · Sunday at 8:03 AM

Cohl said:
How thick should the metal be (both) for a 24 and a 30 ft ship?

I searched on Google it tells me 8mm to 10mm and I can't even find sheets that thick. I just searched it again today and it says 3 to 6mm thick. Google sucks.

It depends on where the steel is being used. Different areas of the hull will require different plate thickness, any where from 3/16" to ½". Using a simple internet converter 3mm is ⅛" and 6 mm is 15/64".

Building and maintaining a steel boat is not for the feint of heart. I'm deep into refitting/completing a steel boat, I'd much rather be working in wood or fiberglass. Steel has a few advantages, mostly strength and impact resistance, maintaining a steel hull and dealing with rust and corrosion is a big job and the electrical design is complicated by the steel hull.

dlochner · Sunday at 8:16 AM

Cohl said:
Thanks so you think the deck should be 3mm and the hull 6mm just to confirm?

I'm not a Naval Architect so, I won't advise on scantlings. Sorry.

Aluminum also has issues and is even more reactive than steel. Corrosion and galvanic action can be a real issue.

colemj · Sunday at 8:20 AM

Are you building a metal boat to existing plans? If so, they should tell you which metal, how thick, and where it should be placed.

If freewheeling a design, then I think you should know this stuff before getting into it. Google and this forum probably aren't the best resources for that.

Mark

dlochner · Sunday at 10:11 AM

Cohl said:
Well if nobody here does there own repairs then your right this definitely isn't the place for me.

Although many of us do repair out own boats, very few, if any, SBO members have steel or aluminum boats. The advice and guidance you might get here will be limited.

Try searching for a metal boat forum, there is probably at least one out there.

Tally Ho · Sunday at 11:31 AM

These “kids” built a steel boat by themselves, from scratch, in California. The girl was the primary welder.

They have now retired and Emerald Steel was sold (I think).

Watch the early episodes when the designed and built the boat. Quite a fascinating life they have lived.

Sailing Emerald Steel

LIVING THE DREAM ON A LOW BUDGET For 30 YEARS!! We gave up many of the trappings of a materialistic world in exchange for freedom from entanglements .This channel is more then just about sailing... It's about 2 young people that fell in love and worked hard to accomplish their dream. After...

youtube.com

Greg

dLj · Sunday at 1:12 PM

Your first post:

Cohl said:
How thick should the metal be (both) for a 24 and a 30 ft ship?

I searched on Google it tells me 8mm to 10mm and I can't even find sheets that thick. I just searched it again today and it says 3 to 6mm thick. Google sucks.

Some of us here have quite a bit of steel boat experience.

There is so much missing information in that question - I would need to ask many questions to even begin to address what you seem to be looking for...

Then you post:

Cohl said:
Well if nobody here does there own repairs then your right this definitely isn't the place for me.

Not only do I do my own repairs, I also do a whole lot more...

But you know? You may be right. This may not be the place for you. Go try Sailing Anarchy.

dj

shemandr · Sunday at 8:36 PM

Over a period of about a year I watched a guy build a steel vessel of around 40'. He used it for tours of the East End of LI. At first I couldn't believe he was building a boat. He worked largely by himself and outside. Trucks would deliver materials and he would set up frames station by station and weld them himself. I regret I didn't approach him to teach me to weld but I think he would not wanted to slow down for that. Sooner than I expected he was welding steel panels on the frames and went on to finish the hull. I think the boat moved somewhere to be finished. It did go on for touring for a while and was sold out of the area. I was amazed that one guy could manage that project pretty much by himself.
I have no idea what thickness the plates were. But in steel hull construction there isn't much bending. The design has to have pretty flat panels. I think it's interesting that the build material dictates the shape of the boat to a large degree.

dLj · Sunday at 10:22 PM

shemandr said:
Over a period of about a year I watched a guy build a steel vessel of around 40'. He used it for tours of the East End of LI. At first I couldn't believe he was building a boat. He worked largely by himself and outside. Trucks would deliver materials and he would set up frames station by station and weld them himself. I regret I didn't approach him to teach me to weld but I think he would not wanted to slow down for that. Sooner than I expected he was welding steel panels on the frames and went on to finish the hull. I think the boat moved somewhere to be finished. It did go on for touring for a while and was sold out of the area. I was amazed that one guy could manage that project pretty much by himself.
I have no idea what thickness the plates were. But in steel hull construction there isn't much bending. The design has to have pretty flat panels. I think it's interesting that the build material dictates the shape of the boat to a large degree.

Steel boats are not difficult to build really.

There are a number of ways to build them - not all methods produce hard chine boats. Brent Swan used to have designs he called "Origami" boats. There were no stringers - the steel plates were bent into shape with come-a-longs and welded in place. Using that method you ended up with curved smooth sided boats. He used to say you could build one of his boats in about 6 months. I imagine that would be with fairly utilitarian interiors and working long days every day. His designs were aimed at home building. He was actually on here a few years ago for a short while. I haven't heard anything about him in some time now. I used to see him in various forums. He would design a boat for you. He also had a book you could buy. I never saw any stability curves for his boat designs however - but maybe I just haven't seen them.

You've also got Zeyang Lin in Norway that built a large aluminum hull boat all with volunteers - he called his project "Sailing the Farm". Had a Facebook group but it hasn't been active in about 3 years.
https://www.facebook.com/groups/138...86poxtZqeEwjDqrJZ8QdNYzVUMGQ&__tn__=,d-UC,P-R
So no, you don't have to just use only flat panels - at least as an end product...

dj

colemj · Monday at 4:31 AM

Cohl said:
Well if nobody here does there own repairs then your right this definitely isn't the place for me.

You haven't described what you are doing. Are you repairing an existing boat? If so, then wouldn't the steel adjacent to the damage, or the corresponding steel opposite of the damage guide you to the type and size?

I have no experience with steel boats, but a lot of experience with fiberglass. There isn't much difference in this - if I am doing a repair, I take into account the adjacent scantlings and structure, or those on the mirror side of the boat, in guiding me.

Mark