Lobsterboat characteristics.

Thanks for those links: my iPad thingy can't view them unfortunately.

If the Range boat is such a good design that can save 100% in fuel consumption at 14kts why aren't all boats made this way?
What are the disadvantages/compromises of this hull form?
Where does this design get it's directional stability from without a keel/Skeg/deadrise?

 

Thanks, that's a very interesting boat.

 

Well four pages of silliness and you're still missing the point. It doesn't matter what the boat is called; Lobsterboat, Rangeboat, commuter, or Wally......It will be efficient (burn less fuel for equal speed) in direct proportion to it's weight(displacement) per unit of length. Long, skinny, lightweight boats use less fuel than short, wide, heavy ones....that's it.

The Rangeboat is efficient, it's also tiny and empty inside, rolls, has limited range, and is lightly (expensive) built. Those are the compromises, Lobsterboats throw a big wake because they are big, wide, heavily built hulls going fast. The Parker commuter is easily pushed because it's narrow, has nothing inside, is lightly built and has an almost flat bottom, try running that in a sea.

A lightly built Lobsterboat running at moderate speed throws very little wake.



The same hull being pushed throws a lot of spray, but still not much wake...

 

Tell that to the tens of thousands of generator diesels that are constant RPM at 1500 (50hz) or 1800 (60hz) and do not seem to mind running many thousands of hours.

In the lifespan of a pleasure boat, and especially the period of time any one owner will own any one pleasure boat, I doubt any of that conventional "wisdom" plays a part in reality.

 

One of the automotive disasters was the VW 120hp diesel sold under the Merc brand as a I/O for lightweight boats like the small angling boat the Arvor 23' available in Europe. Most The engines and turbos had to be rebuilt several times during the first year!

A Serious challenge to VW's reputation for reliability, highlighting the difficulty of making car engines take the continuos high load in a boat.

 

I have looked at boats (out of water) used for fishing lobsters in the Outer Hebrides. Not much similar to the boats used for lobstering in Maine. Fundamentally different hull shapes.

 

>This probably why there are very few diesel engines that have successfully transferred from cars to boats.<

<A Serious challenge to VW's reputation for reliability, highlighting the difficulty of making car engines take the continuos high load in a boat.<

There is your answer , car engines have very minor loads most of their life.

40 mpg at 80 mph is 2 gal per hour , perhaps 40 hp . Regardless of the advertised HP, this is the long term rating for the engine.

Trucks dragging 80,000lbs up hills is a closer match to a boat , where its ALL uphill!

Folks desiring low cost boating need to get over the NEW , NEW ,NEW fixation and realize HD truck and industrial rated engines can be rebuilt easily.

$4,000 for a used engine vs $25,000 for basically identical unit pays for a lot of diesel.

YES the early engine will have mechanical injection so burn a few % more per hour , but a lightning strike 1/2 mile away wont blow a $10,000 computer.

 

Problem with buying an old truck engine is the cost of marinising the engine; although it would be very cheap with a keel cooling and dry stack setup normally found on displ boats. You would also have fabricate your own adaptor plate for the gearbox unless you could buy an old gearbox with the correct bell housing.

The reconditioned Cummins seem to offer a cheap option for re-powering and come with all the cooling gear.