Any super economical motorboats out there?

http://www.boatdesign.net/forums/boat-building/my-little-piece-peace-25962-121.html#post499727 40ft loa/lwl, 21 ft beam, 4000 (+fuel) kg 6.7 knot cruise on 3 litres/hour... (3 Litres = 0.7925186 imperial gallons)

Present maximum fuel capacity is around 1860 litres (at 1500kg, according to tankage available) giving an estimated range of 3720 nautical miles

 

I say it again get a boat that can power and sail. With the distance you want to go there will be motor break downs and sailing is great on fuel economy. There are enough 24-26 foot trailer sailers with drop down rigging that will do the job with inboard or OB power. A folding 28ft corsair tri. would even work economical under power and fast flat sailers(no pack ratting)

 

I have a very old (1934) power boat 45 feet long 19.5 tons displacement powered by a 1955 vintage Cummins diesel. We cruise at slightly better than 4 mpg, very reliable 1.5 imperial gallons/ hour at 7 knots. I know one or two others that are pretty close to this consumption but most of the similar sized boats I know burn between 2.5 and 4 gph for a similar speed. Interestingly my brother has a similar sized boat (1928) with the original Gardner diesel, and gets closer to 6 mpg.
Most power boats are designed around the accommodation and styling. Little thought is given to economy.
Engine, transmission, and propeller must be correctly mated. and the hull driven at an economical speed. Generally I suspect few modern engines which are designed to get their horsepower by whizzing around faster will either get the longevity or efficiency found on the older boats noted above.
I like the idea of power cats, but suspect with the modest scale of your plans (Albin 25) would make it difficult to find one with sufficient capacity.

 

eyshulman, i really dont think a trailer sailer would be a good choice as even a larger size one around,say,25ft has a tiny interior and a cockpit very exposed to the elements when compared to a powerboat. With this route you are following the seasons and my guess is that you could well end up doing a bit of cruising in not so comfortable conditions, hell,even in the summer in the great lakes it can be cold, if you look at the Albin 25 it has a very protected helm,the cockpit can be fully enclosed with canvas and with a schoolbus heater running off the diesel coolant could be downright cosy, its small enough for i guy to get through the locks in the Erie canal and gets great mpg, i know of no comparable production boat so well suited for this trip, i have learned of a few more on this thread so the list now looks like this.
Albin 25
Albin 25 motorsailor
Albin 27 motorsailor
Permacraft 25
Tiderunner 23
Bayliner Explorer 2670 maybe
All of these except the Albin 27 motorsailor can be had for in the $10-20000 price range and should get 10-15mpg, the bayliner is not quite as economical but with cheaper fuel may be in the hunt.
Ok, my choice would be the Albin 27 MS but they are not easy to find and are above the $20 grand, so, so far the Albin 25 fills the bill best i think, i would extend the hardtop the full length of the cockpit so i can carry a kayak or two up there and add full enclosure side curtains, add a schoolbus heater in the cockpit and down in the cabin and possibly extend the transom 2ft to get a bit more waterline length and swim platform. I love powercats but i dont know any that fit my SOR, there are many older Taiwanese trawlers in the lower to mid 30s size range with single diesels that would be great to live and cruise on but they all seem to get about 4mpg which is not good enough.
Steve.

 

Actually the correct designation of the Albin 27 ms is Albin 82 MS, apparently only 3 in the US so im not likely to find one of these. Claim is 1.8 l/h at 6 knots cruise, 2.8 l/h at WOT with 3GM30. This is excellent if correct. Perfect boat for my purpose imho.
Steve.

 

Albin boats are common in Sweden. 30 seconds spent with Google revealed that there are at least two Albin 82 for sale right now, and six more have been for sale this year. You could buy it here and sail it to the US. The North Sea in winter should be an interresting experience.

Albin 82 is 8.2 m long and displaces 3400 kg according to the sales bruschure. 6 knots is a likely speed from 10 hp (corresponds to 1.8 liters/h). The original engine was 35 hp, so 6 -7 liters/h should be expected at WOT.

Erik

 

Not giving up yet. How about a Marshall 22 cat boat. LWL 21.4 beam 10.2 draft board down 5.2 board up 2ft. Disp. 5660 lb. Dont let the 22ft fool you this is a very big boat for its LOA and by WL and beam is equal to many 27 footers. Now if you make a canvas or solid wheel house in forward part of the large cockpit you have shelter. Then if you remove mast and store rig for resale you can replace with a shorter folding rig of say 200 sq foot. the small inboard deisel motor and this rig will give great economy. While these boats are not designed to cross oceans they did work the new england area as lobstr boats under some bad conditions. Similar boats have been used for the snowbird migration up and down east coast. The shoal draft with board up will allow for great gunk hole anchoring and will also easily beach. My advice is not coming from a drawing board but from >50yrs of sailing and powering on waters like ICW and coastal with some river and lock included.

 

Erik,i really think they did a great job with the Albin 82 design, it is a very good looking boat considering the size, i currently have an Aloha 8.2 m sloop built in Canada which i wouldnt want to do this trip with, it just does not motor well enough with just 7hp.
eyschulman, i am familiar with the catboats,they are huge for their length,ive been on an Atlantic city catboat which at 24ft is enormous. They get a lot of money for catboats though. No, i still think the Albin 25 is the most practical so far. A local guy has one i could probably get fairly cheap but its a bit more of a project than im after, the albin 21hp diesel is worn out so he bought a supposedly good running takeout which needs installing but id be inclined to install a new Beta or Yanmar or similar. It needs lots of work besides the engine install so im more likely to buy one in good shape, do the trip and then sell it.
Steve.

 

Almost any sailboat or a motorboat with similar hull (true displacement hull) in 25-35' size range can do 0.3 l/NM (about 15 mpg) at about 80% hull speed.

My old sailboat was 28' and 2900 kg. It did 5.7 knots at about 1 l/h with Yanmar 1GM10, thus less than 0.2 l/NM (over 22 mpg). My current boat (35', 5800 kg 19 hp VP) takes about 2.5 l/h at 6.5 knots, thus less than 0.4 l/NM (over 11 mpg). I'm sure at 6 kn it would be over 15 mpg.

These boat have rather heavy keels (1 and 2 tn), masts and folding propellers. If they were optimized as low consumption motor boats, they would have clearly lower consumption.

At least around here this type of motor boats are very seldom. Most are over powered and have more or less semidisplacement hulls for higher than true displacement speeds. There used to be lots of them over 30 years ago, but since then everybody wants to go faster despite big waves, more noise and much higher fuel consumption.

 

This is exactly why i started this thread, true displacement motorboats are not common here either and i am interested in finding info on any that are out there that i dont know about and we have turned up a few, it is very frustrating as we all know how economical sailboats are under power,most sailboats however are not great motorboats as they tend to have that "living down in the basement" layout with little protection from the elements in the cockpit without lots of canvaswork, and also too much draft for inland river cruising. Fortunatly there is always the old Albin 25 which i would be quite happy with and are plentiful and reasonably priced.
Steve.

 

This is what you are looking for. You will have to build it.

 

A few years ago up the BC coast I met a British couple with a small powerboat they had shipped over-had a huge aft cabin and I was impressed by the use of space.
Can't remember what it was called but maybe i can look through my pix and find it.

I saw many boats that would be perfect while cruising the British canals...but they're in the canals and not in NA.

 

Here it is....Elysian 27 centre cockpit.

http://www.apolloduck.com/feature.phtml?id=212121

 

There IS a point where the cost of low fuel burn is out weighed by the hassles required.

Perhaps a custom built very light boat could get 15mpg , but the cost and time to build it would out weigh any fuel savings.

Find out if you can get parts for an Albin's powerplant , go slow , and GO!

"Paint" sells da boat , so by cleaning , polishing and painting as you cruise you might be able to go from the lower price range to a higher price range with almost Zero money , but loads of sweat equity.

That could make the 1/2 gph fuel burn /5K easier to live with.

FF

 

My Willard does quite good for a small boat but is not optimized for MPG. If one took out the ballast, cleaned up the shape of the keel and installed a 20 to 25hp diesel chosen for it's fuel efficiency along with a 3-1 gear (or a bit deeper ratio) the Willard would do a lot better than it's normal 6mpg. But a good W30 will cost $30 to $50K and the mods would be $15K on top of that. As Fred says fuel consumption is only a small part of the cost of boating. In Western Canada I remember spending more on moorage while cruising than fuel. In some places anchoring is'nt an option and renting a transient slip is an open door to where ever you are. But if you really want optimal fuel efficiency a striped down sail boat otherwise as-is is probably the cheapest route to minimum investment and maximum MPG.