Small working tugboat

[kengrome]

I'm posting these images for the hull of a small working tugboat I've begun to design.

It's an 11.7 foot boat for towing heavy loads and working in shallow water. It's about 6.5 feet wide and has a box keel and a tunnel-stern like the Atkin Seabright skiffs which means a protected prop and rudder (not yet shown).

It's not designed for semi-planing speeds, this one is strictly a displacement speed hull with the specified 5-10 HP inboard diesel. It should be easy to build in plywood, there's only a little bit of twist in the bottom panels, the rest of the hull is just simple bends. I'm thinking of plywood / epoxy / fiberglass composite sandwich construction but I suppose any sheet material would work.

Comments welcome, but remember it's not finished yet ...

[aztek]

lovin the boat

[Village_Idiot]

Maybe consider enclosing the prop totally inside a tube or at least a shroud. This should increase thrust, especially if you can keep the prop tips close to the wall of the tube/shroud, say within 0.5% of the prop blade length. Sort of like a tractor jet, but with better efficiency.

I still like the idea of a transverse tube in the bow (below waterline) with a TMD (tip magnetic driven) prop that could be used as a bow thruster - but it's probably overkill for this project...

[robmill54]

I like it, it looks a lot like the 14ft Candu E_Z tug. I have the plans for it and it's close.
What program are you using to design this?

[kengrome]

I used FreeShip 2.6. The original file was sent to me from someone else, but I remember that the boat started as a 9 footer before I enlarged it just enough to make it useful -- and totally changed the bottom. If there's a 9 foot version of the Candu E_Z maybe that's where the original file was drawn from?

The person shown is sitting and if he wants to stand in the house it's going to have to be taller, I can see that.

[robmill54]

Originally Posted by kengrome

I used FreeShip 2.6. The original file was sent to me from someone else, but I remember that the boat started as a 9 footer before I enlarged it just enough to make it useful -- and totally changed the bottom. If there's a 9 foot version of the Candu E_Z maybe that's where the original file was drawn from?

The person shown is sitting and if he wants to stand in the house it's going to have to be taller, I can see that.

Thanks, there is a 11ft model here is the link;


http://www.berkeley-engineering.com/CanduJr.html

[kengrome]

Cute design, and almost the same as mine from outward appearance. The bottom is probably much different though because mine has a classic tunnel-stern Seabright bottom and the CanduJr has really huge planing fins which mine does not, but they do look a lot alike from the side.

[Tad]

I doubt this arrangement or hull form makes much sense for a truly useful working boat. Tugs are shaped and arranged the way they are for very good reasons.

The cabin and freeboard forward on this design makes it impossible to get on or off (or work over the bow) easily around a large portion of the boat. A low rail and easy access all around are required, otherwise you have to turn the boat completely around to get off....a waste of time.

Controllability is another key factor in the usefulness of a small tug. This boat has far too much windage and not enough under water. While the shallow draft may be useful on occasion, having the boat blow all over hell and having to constantly goose the throttle to get her to turn will be a constant pain. These tunnel stern boats are notoriously lousy trying to maneuver at zero speed.

We have a couple of very useful ting tugs here in Silva Bay, with relative mouse-power they do a great deal of work. The larger boat is Seka (13'6" LOA), with 6 HP BMW diesel turning a 11" by 8" prop, the smaller boat is Sophie (10'4" LOA), 13HP Beta turning a 12" by 12" wheel. Both boats draw 12-15" of water.

[yosipanji]

After I read this Interesting article from this link http://www.ratson.com, i got an idea to make 3d models and miniaturs of Tug Boat for business & military purpose..

does anyone have other references?

brgds,
yp