1st steel boat, and some designs close to what I think I could live with...

I have been thinking lots lately about building a boat.
I attached pictures of something roughly showing the shape I could go after.
What do you guys think, for a 1st boat?
I realize it isn't going to be 100% perfect, as it's my 1st boat, but at the same time, I don't want to waste a bunch of time and money.

I'm really thinking steel is the answer.
I've been crunching numbers, and I should be able to build a 8' wide 32' long boat and still keep it weight legal for a 1 ton pickup truck.

I haven't stumbled accross any designs for steel hulls that shape or similar, but I will find some somehow.
Hull will be 1/8" steel, and then I'll weld in framing made from 1/8" thick 3" angle iron.
The cabin will be thinner framing, with plastic or tin roof, to keep weight down.
So basically the hull will be a 8x32 or so "tub" looking thing, about 48" high. That plus the drivetrain will be the bulk of the weight.

 

They look like easy boats to build. The first picture is a bit square boxy with no sheer

.....no need for a simple boat to look ugly.

I dont know about towing weight regulations

Be careful.. Steel is heavy and all the tankage, interior comforts on a cruiser add a lot of weight.

Better get your pencil out add start calculating...then add some more kilos.

 

I'd stick to ply fo that application, to make steel comfy you'll need to do some timber fitout which is like building another boat inside, with timber the construction is often the lining & fitout. There's plenty of square meters in a 32' boat, 1/8th plate at about 24kg per M2 they'll add up quick. Jeff.

 

I thought about using plywood and fiberglass, but for several reasons, that went out the window. Too bad they don't make 4x8 sheets of rigid semi-impregnated fiberglass sheets, so you could build easy boats without wood or moulds.

What i'm using for an estimate, is a box. The hull 32 ft long and 8 wide and 4 tall, for eg...
A 4x8 sheet weighs 164 lbs @ 1/8".
That box works out to 2952 lbs of steel in 1/8".
I can't find a design, so I'll have to wing it.
Figure in roughly 2000 - 3000 lbs more for the hull framing.
That would bring the hull weight to 5000 - 6000 lbs.
Considering some half ton trucks now can tow 11,000 lbs, I think this is do-able.

Some might say 48" tall hull is too much, I'm sure others thing it's not enough. At some point, I'm going to need to just go for it, or I'll never do this. I figure with about 48", about 3 ft will sit above the water line.

I will make the entire cabin lightweight, with a tinted plastic transparent roof, and tin roof metal for the sides. As much as it would be nice to insulate the walls of the cabin, I think it would add too much weight. I also don't really know what I'm doing, as this will be my 1st boat, so keeping access to the hull is a great plan, I think.
So basically, it will be all metal in the cabin, with removable floor panels. I will try to make it comfortable without adding insulation or interior walls.
Not the prettiest or most functional, I realize, but for a 1st boat I think it should work out great!

 

I tried to draw out the plans I am thinking of, to the best of my ability.

On the framing diagram, "B" are the "ribs?" that will run from wide to side along the hull skin.
"A" are the pieces that will travel along the ribs lengthwise.
I am thinking both could be spaced about every 16 inches.
I am also thinking both could be 3" angle x 1/8" steel.


There would be extra pieces of frame added also, but this is just the main hull frame I'm thinking of right now.

 

http://www.youtube.com/watch?v=mJFcwRmcBiI

That one is very roughly about the similar size, and shape, and looks like very light framing, am I correct in thinking that framing is way too light on that boat?

 

I found 2 interesting pictures.

One is a boat REALLY close to what I'd go for,
And the other is a picture of a steel hull showing the framework.

Looks like I might as well toss out the angle iron idea, use 3" or 4" strips of 1/8" strapping for the ribs, and then weld in little strapping pieces for the lengthwise strips, and to keep other strips from bending.

Another question, am I correct in assuming the boat in the picture would use more fuel becuase the bottom is flat? I am really trying to understand what the best/easiest design will be.

I am thinking single chine would be relatively easy to do, and should work great. Just curious after seeing the red boat below though.

 

Alright guys, I talked to a local steel supplier, and they are insisting the metal I need to use is pre-washed and oil bathed, does this sound right?

They have 1/8" x 4" strapping to use for all the ribbing too, so I'll need to find a design or come up with one eventually.
If I can't find anything, I'm just going to find as many pictures as I can of steel boats of a similar size, and do my best to Re-apply those techniques as best I can to my boat.
Is this oil bathed steel weatherproof at all?
Will it do alright sitting outside, or will it rust quickly?
What if I just spray the welds with oil after welding to replace the burned off oil?
Or will I need tarps or maybe portable garage to work under?

 

I thought you might want some more options for this build. I have some solid fiberglass sheets 30 foot long,x 5' 8" wide, x 1/4" thick. Weight in average is about 380 pounds per sheet. Mail me a t boatbuilder41@gmail.com for more info and pics. It i lots cheaper than steel and lower maintenance. Build cheaper,an last forever with low maintenace. One sie is already slick making sanding and fairing very minimal. I build using these daily.my latest build is featured in NATIONAL FISHERMAN MAGAZINE MARCH 2013. I ALSO HAVE A FEW PICS OF THIS BOAT IN MY GALLERY. I JUST THOUGHT YOU COULD USE ANOTHER MATERIAL OPTION.

 

Are those sheets something you buy, or you make?
I am interested to learn fiberglass, but I feel insecure about it cause I've never used it much.

So with the sheets, you can design the hull without a mould then, is that the idea?

 

With minimal temporary fraiming it allows me to adjust flare, bow lift,and rake. Its great when your building from scratch. Sometimes i dont know what im gonna build. I just temporary frame,stand back, and walk around it for a couple hours, get a virtual image in my mind, tear it apart, and start over

 

I can picture myself doing just as you describe.

So the panels, for some reason I imagine it would be hard for epoxy glass to stick to them? Maybe I'm wrong?
Having trouble imagining what they would be like to work with I suppose.

 

Well after steel place looked around yesterday, only 1 producer has what I need.
And a 4x8x/1/8" sheet comes to 104$ each.
1/8" x 4" strapping is 40$ for each 20 ft length.
I would need some other pieces and sizes too, but those would be the most used.

Years ago I worked at a welding shop, and we welded horse trailers.
Those were mostly 16 gauge steel.
1/8" should be 11 gauge, so this boat should be at least as strong as a horse trailer haha. (if built properly, obviously.)

 

Epoxy stick great..i am going to take a pic or two.

 

Do yourself a *huge* favour and peruse some of the threads on metal boat building both on this site and others.

Then go and buy some of the classic recommended texts written by people who've actually built boats in steel.

Then you will ask questions that at least have some novelty..... we have done the steel plate issue (pickled & oiled vs blasted & primed vs building first, blasting after etc etc) to death.

If you buy a set of plans the designer will *tell* you what sizes & shapes of steel to use. All you then have to do is follow the plans.

PDW