Small Steel Workboat Design

Glen-L often details out an outboard option. look up client build pictures of this and other tugs. You can design your own cabin to suit your needs. more HP will give it to you as well as some pitch changes to the bottom frames and a redraw of the transom for an outboard. Glen-L has a great forum also and you can find someone who has built that model. many make lots of changes

 

What gauge did you have in mind to be using ?

 

A small steel boat is always going to be heavy, maybe 7-900kg for a 18-20 footer with some stuff aboard, An outboard is a terrific option, steering gearbox & engine in the one neat unit, portable tank & hose ... off you go!
Anything under 2.5mm really doesn't belong in a saltwater environment, as much as coatings can be good scratches happen, your weldout will be easier with thicker plate, go 3mm, nice pipe sponson/gunnel & accept that small & steel will be "heavy".
Speed will be lower............. with a heavier boat, your going to be in displacement mode & 5-6 knots.

For translation, just copy & paste the text into a "google translator", the phrasiology will be a bit different but understandable, that article is more about young blokes having some fun than design & building though

Jeff.

 

Wanting to cruise at 7 knots makes this a little difficult, a 16' heavyweight boat, regardless of hull form, will not be happy at that speed. If you want to run faster, say 15 knot cruise with a planing hull ( possible with a beamy, flattish bottom) you will need 80 or 90 hp on the back.

 

Jeff, I agree with you that anything less than 2.5 in salt water is not a good idea. I often work on larger steel boats 60ft +, I have re-plated a few, hence my desire to avoid thin plate.

So thats one reason I want to build from 3mm, the other is, that its much quicker to weld and easier to fair.

Mr Efficiency, i think Im going to have to accept that the boat i need, and can afford to build will have to have a max speed of 5-6 knots, thats ok.

I like displacement hulls, I find them more fuel efficient (maybe Im wrong?) and Im rarely in a hurry. I feel safer in a boat thats riding "in" the water rather than one thats riding "on".

Having said that, my knowledge and experience is very limited, just tugboats and planing dinghies.

 

Rasorinc, thanks for the tips.
Sweet 16, seems to be the only realistic candidate so-far.
I dont really want or need a cabin, which would make for a quicker build.
I assume I would then have more weight carrying capacity?

 

You might go to the Glen-L site and look at their Pacific Dory's. All outboards, very easy builds and easy to make changes. Work well in heavy water and can carry huge weight. Stan They have them from 13' to 26' + 10%

 

There are couple of old threads about small steel boats:

http://www.boatdesign.net/forums/metal-boat-building/steel-dinghies-8856.html

http://www.boatdesign.net/forums/metal-boat-building/my-one-sheet-steel-boat-project-28485.html

Few designs:
http://www.bootdesign.eu/home/17
http://www.dutch-barges.net/

 

Milan, thanks that's very helpful
http://www.bootdesign.eu/home/17 looks really interesting
The "Billy 500" looks like it might fit the bill, just need to translate page now

 

I have decided to build my own design in steel,
After all, what could possibly go wrong

I have done the drawings, and worked out the frames,
It is 15ft 8" length
6ft 10" beam
It's a hard chine boat with 3 planks/strips
Each side
Sharp bow, and I've put in a rocker in the bottom.

As I'm building from 3mm plate, I'm going to use minimum framing,
Heavily relying for strength on a semi monococ design using a foredeck and side decks, also welded flotation tanks fore&aft will add rigidity.
I will also be adding an out board well , again I can use this to gain structural strength. A water tight floor will be welded in to add safety, and will be filled
with foam. And a combing to top it off.

I've drawn up the panels, and calculated the weight at 300 kgs, dry weight.



on a hard chine

 

Oops, forgot to add weight of outboard well and combings
340 kgs dry wieght

 

a heavy steel workboat, no kidding,
its just what you need
i guess your N A is not dutch

 

Your right there, he's English.
His comments were that, "years ago he used to build small Line Boats (25ft), the feedback he received from clients was that they were Unstable, so he had to greatly increase Beam to correct this."

 

In the Netherlands there is a popular boat called the Lelievlet. They are used by the scouting, and over 1500 have been built.

Wikipedia: http://en.wikipedia.org/wiki/Lelievlet

Build Video: https://www.youtube.com/watch?v=06_eI0PqwV8

Build instructions and plans: http://bds.home.xs4all.nl/lelievlet/De_lelievlet_8e_druk.pdf

In Dutch but very comprehensive and many construction details shown.

-Thomas

 

Thomas, thanks so much for the links
What a beautiful boat, I love it!

This is exactly what ive been looking for!
5.6 meters is a bit big for me, however if I can build it to 4.8 meters then I think that this is perfect for me.


Would a 15hp outboard be enough power for propulsion?