Fuel consumption for Hankinson tug

[JimD]

Let's say I was going to build something like this:

GOLIATH

#028 an 18'6" tug for work or pleasure
by Al Sorenson & Ken Hankinson Build in
PLYWOOD, ALUMINUM, STEEL

http://glen-l.com/designs/hankinson/kh-images/028goliath-l.gif
CATEGORY: Tug yachts
CONSTRUCTION: Sheet plywood/wood framing, or welded aluminum or steel
Characteristics Length overall 18'6" Beam 7'2" Draft 2'6" Displacement 3300 lbs. Suggested power range 5-20HP Speed within HP range 5.5 kts. Fuel capacity 30 gals. Looking much like any other steel boat in progress, the novel SHRINK-WRAP techniques make construction quicker and more accurate. These amateur-proven methods assure super-smooth, fair surfaces virtually free of distortion. Fairing and filling compounds are virtually unnecessary. The final boat is so fair it might be confused with one molded in fiberglass.


And let's say I was going to power her with either a 10 hp inboard diesel or outboard gas engine. Cruising at 4 to 5 knots anyone have a fair guestimate as to how many miles to the gallon (or litre) could I expect?

[paladin]

I have a similar unit in draw right now...ballasted...a true displacement hull, and if you hold it to hull speeds of about 5.5-6.5 knots the fuel should be less than i liter per hour......I am basing mine on a 20+ hp diesel turning a rather large prop with a large reduction, and at reduced rpms for long range cruising.

[JimD]

That would be about a dollar per hour per five miles at current fuel prices. Even if they double over the next few years we could holiday around the Gulf Islands cheaply and comfortably. A further description of these designs includes:

...these are serious vessels meant for work or pleasure. They feature deep-draft, heavy-displacement hulls for the motion and feel of little ships. With their oversize props, big rudders, and deep keels, these boats can turn on a dime and punch through seas that would stop or flail about less-able "flyweights" of similar length...

[willmarsh3]

I have a 32 foot 12000 lb displacement steel vessel w/ a 24hp diesel. She uses miniscule fuel - about 10 mpg at 5.5 knots. Or about 2 liters per hour. This is running at 1800 rpm with a 2:1 reduction turning a 3 bladed prop approximately 13x13 in size. I think these figures would scale down roughly to 1/3 to 1/2 for the tug given the dimensions.

BTW that is a pretty cool design. I hope you decide to build her and if you do pls post pictures here and/or in the Metal Boat Society.

[Rob Stokes, N. Vancouver]

you could even extend the cabin a wee bit, incorporate a galley and some sittin' space and still keep the lines :)

http://www.robswoodworking.com/images/Temp/tug.JPG

http://www.%20robswoodworking.com/images/Temp/tug.JPG

[JimD]

BTW that is a pretty cool design. I hope you decide to build her and if you do pls post pictures here and/or in the Metal Boat Society.

I would be very happy with this design. My first choice would still be a small motor sailer but a wheelhouse with standing headroom is a rather tall order for a sailboat in the 18-20 foot range. Cathy (Mrs JimD) also really likes the tugboat concept and given the choice between the tug or a pure sailer of similar length the tug may very well win out. I've already changed my mind about a hundred times over the past couple years on the right boat for holidaying in the Gulf Islands. But now that we finally live here and see the type of boats that actually spend a fair amount of time on the water not many of them are sailboats, or else they are motoring with the sails down.

[RonW]

Jim, hankinson's tugboats are first class and very neat and usefull.
I am glad to see that the plans are available again for who ever wants one. I will make the suggestion that if you do build one, try and go the steel route, and if not steel, then heavy frames and strip planking or heavy carvel, but not plywood. I just think these tugs ought to be heavily and well built and deserve better then ply.

[JimD]

Jim, hankinson's tugboats are first class and very neat and usefull.
I am glad to see that the plans are available again for who ever wants one. I will make the suggestion that if you do build one, try and go the steel route, and if not steel, then heavy frames and strip planking or heavy carvel, but not plywood. I just think these tugs ought to be heavily and well built and deserve better then ply.

Ron, for better or worse I would build in plywood. I'm not about to start welding or strip planking and I believe plywood can be done very well. I would sheath both inside and out.

[Paul Fitzgerald]

Diesel consumption is around 0.2 liters per Hp per hour.
Four stroke around 0.25 liters per Hp per hour.
Two stroke around 0.4 liters per Hp per hour.

[RonW]

I also just noticed that you mentioned outboard, in your first post, that little tug is designed with a massive prop on it.
But hankinson does have a slightly bigger tug style boat, for outboard power and would be perfect in plywood.Check it out.

http://glen-l.com/designs/hankinson/vandal.html

http://glen-l.com/designs/hankinson/kh-images/057vandal-shert5.jpg

[JimD]

Vandal only looks like a tug. Its actually a fast planing hull good for towing skiers. I would consider an outboard in Goliath only in a well in the cockpit and I would search for a slow turning engine with a larger prop, possibly such as the ones offered by Yamaha that are meant for displacement hulls.

[Spokaloo]

Jim, looks like it will fit in wonderfully in the Gulf/Sunshine coast/San Juans. Your right about the sailboats, nobody ever seems to have their sails up much. Id have to say the Oysta boats that Sam Devlin has been kicking out are a pretty close fit as well, and a motorsailer to boot.

Or I could bring my 9' tug out!

E

[JimD]

Those Oysta designs are among my favourite but way outside our means. And Cathy really likes the look and concept of a small heavy tug. Plenty of creature comfort, economy, safety, low stress boating, and style. I've had tunnel vision for the past couple years focused on sailboats and if it were just for me it would definitely be a sailboat but for us this tug has actually got me excited! Gonna order the study plans tonite. :)

[Mark T]

I ordered study plans for the 20 and 26 foot designs . Appear to be the same vessel,can't wait to get them. I've been hunting for a low to mid 20's design for quite some time. Was looking at the 25 footer that Jay Benford has but the design is in steel. I do want a wood hull. Cost to have the plans converted to wood is expensive.

[RonW]

Here is a 24 foot wood tug.....

http://www.boat-links.com/Atkinco/Misc/JudgeHooker.html

[JimD]

Here is a 24 foot wood tug.....

http://www.boat-links.com/Atkinco/Misc/JudgeHooker.html

http://www.boat-links.com/Atkinco/Photos/JudgeHooker/JudgeHooker-02.jpg

http://www.boat-links.com/Atkinco/Photos/JudgeHooker/JudgeHooker-01.jpg

http://www.boat-links.com/Atkinco/Misc/images/JudgeHooker-3.gif

[JimD]

Sorenson/Hankinson Fred Murphy:

https://www.boatdesigns.com/images/027fredmur-28B.jpg

[JimD]

I ordered study plans for the 20 and 26 foot designs . Appear to be the same vessel,can't wait to get them. I've been hunting for a low to mid 20's design for quite some time. Was looking at the 25 footer that Jay Benford has but the design is in steel. I do want a wood hull. Cost to have the plans converted to wood is expensive.

Had a look at McNaughton's Bufflehead?

Bufflehead
http://www.macnaughtongroup.com/buffle1.gifhttp://www.macnaughtongroup.com/buffle2.gifhttp://www.macnaughtongroup.com/buffle3.gifYou could have a wonderful winter taking Bufflehead down the East Coast Intracoastal Waterway. The dinghy on the cabin top can be a sailing dinghy for exploring creeks and harbors.
LOA 22' LWL 22' Beam 9' Draft (varies with engine & propeller choice)
Whereas Bantam (http://www.macnaughtongroup.com/bantam.htm)is fundamentally a work boat that has found a lot of appreciation as a yacht, Bufflehead is planned from the start as a cruising boat. She retains the character and construction of the smaller boat, but provides a larger cabin with two berths, a galley in the wheel house, and an enclosed head, all with standing headroom. The aft deck is still large enough for deck chairs, and a small pram can be lifted onto the cabin top with the derrick. There is a large storage area forward, which could offer a couple more berths if the fore deck was raised to the height of the rails, in the form of a turtleback.
Modest as this investment would be, one could have a wonderful winter cruising South from Maine along the Intracoastal Waterway as far south as you cared to go. A tiny single cylinder diesel is plenty for this boat so the only significant cost for the winter is your food! That little pram can even be a sailing dinghy for a little gentle evening’s exploration in an intriguing spot.

http://www.macnaughtongroup.com/bufflehe.htm

[Tom Robb]

JimD,
What's the shrink wrap technique?
Tom

[JimD]

JimD,
What's the shrink wrap technique?
Tom

Tom, apparently this:

Looking much like any other steel boat in progress, the novel "Shrink-Wrap" techniques make construction quicker and more-accurate. These amateur-proven methods assure super-smooth, fair surfaces virtually free of distortion. Fairing and filling compounds are virtually unnecessary. The final boat is so fair it might be confused with one molded in fiberglass.
Five photos at right & below from Kari Ruuth who is building his "Fred Murphy" in Finland in steel. Note the fair plating surfaces possible as a result of Mr. Ruuth's care and craftsmanship applied to our "Shrink-Wrap" methods.
http://glen-l.com/designs/hankinson/kh-images/027fredmur-kariru1.jpg http://glen-l.com/designs/hankinson/kh-images/027fredmur-kariru2.jpg http://glen-l.com/designs/hankinson/kh-images/027fredmur-kariru3.jpg http://glen-l.com/designs/hankinson/kh-images/027fredmur-kariru4.jpg http://glen-l.com/designs/hankinson/kh-images/027fredmur-kariru5.jpg
Photos of the Sorenson Steel shrink wrap process (http://glen-l.com/designs/hankinson/steel-shrink.html)
About our Mini-Tugs (http://glen-l.com/designs/hankinson/tugs.html)

About Al Sorenson & his metal boats... (http://glen-l.com/designs/hankinson/steel-shrink.html#sorenson)
SHRINK WRAP STEEL

This admittedly low-tech and forgiving variation on steel boatbuilding is ideal for the short-handed do-it-yourself boatbuilder who can weld, and who wants a small steel boat that will look great. While in use, the process looks much like any other steel boat in progress. But we’ve perfected some novel techniques making construction quicker and more accurate. At the same time our methods allow the use of thinner plates than is typical so that the work is easier and the completed boats are not too heavy. Finally, our SHRINK-WRAP methods assure super-smooth, fair surfaces virtually free of welding distortion. The need for surface fairing and filling compounds becomes largely unnecessary. As these photos show, final hull surfaces end up so fair that they might be confused with a molded fiberglass boat. SHRINK-WRAP methods are used for all our steel MINI-TUGBOAT designs.
STEEL SHRINK-WRAP METHODS IN PROGRESS

The photos below show the Sorenson steel boatbuilding methods in progress building the FRED MURPHY design.
http://glen-l.com/designs/hankinson/other-images/shrink-wrap-1.jpg http://glen-l.com/designs/hankinson/other-images/shrink-wrap-2.jpg Fig 1 - Hull is built upside down over light frame having straight line contours between sheer and chine, and chine and keel. Round bars back up longitudinal junctions at chines and sheer.
Fig 2 - Flat bar longitudinal stiffeners are bent around and notched into frames, but not welded. Thin "door-skin" plywood is used to make templates of plating areas because they are lightweight and easy to fit with accuracy. Once cut, these are traced around over the plates which are then cut and welded in place around perimeters.
http://glen-l.com/designs/hankinson/other-images/shrink-wrap-3.jpg http://glen-l.com/designs/hankinson/other-images/shrink-wrap-4.jpg Fig 3 - Note the smooth hull surfaces. Panels are welded only around perimeters at this stage. Interior welding largely takes place after righting the hull.
Fig 4 - Righting a hull is not as difficult as many think. Most attention has to be paid to letting the hull down in the right side up position. A chain hoist, fork lift, light crane or similar means is helpful in this regard.
http://glen-l.com/designs/hankinson/other-images/shrink-wrap-5.jpg http://glen-l.com/designs/hankinson/other-images/shrink-wrap-6.jpg Fig 5 - Flat bar stiffeners previously in place are now bent to the plating from inside and lightly welded to it. Stiffeners are in turn lightly welded to the frame. But frames are NOT welded to the plating. The result is fair, smooth plating surfaces as the next photo shows.
Fig 6 - Completed FRED MURPHY - the hull is so fair you’d never guess it was a welded steel boat.

About Al Sorenson & his metal boats...

While now retired and no longer building boats, Al always thought like an amateur builder even though his work was of professional stature. The care and quality of his design work has garnered the admiration of professional designers and boatbuilders nationwide.
Once one of his steel tugs was inadvertently docked near a classic wooden in-water boat show and won the "people’s choice" award. While not an official entry and an embarrassment to him, the judges let it stand since the boat did have a wood cabin and Al was a local institution. More to the point, the steel hull was so fair and true due to his simple, proven methods that no one could tell it was a steel boat.
These qualities of Al’s work are reflected in the metal tug plans we offer. Because he has largely worked alone, Al knows what an amateur is up against. Thus he’s refined and developed his methods based on this condition, and we’ve worked it all into our plans and building manuals so you too can achieve professional results with a minimum of work.