225hp lehman

I am looking a boat that had been repowered with a 225 lehman* Are these turbo motors as reliable as the 120?

225 lehman

Will need to be operated at 5-8 GPH for best economy and service life.

Will you be operating at 12K ? or is the boat 50-75 tons displacement?

It is in a 44' marine trader so probably more like 15ton yes?

probably more like 15ton

A ton is 2240 lbs , and is not the USCG "Documented tons" found carved into the main beam. That is volume.

Most boats will require 2 hp per ton for cheap cruise , 3 per ton for inshore close to fuel cruising and most hulls are overpowered at 5hp per ton, unless its a plaining boat.

The archives will have loads of opinions on what happens with a too large engine.

Search underloading.

my C&L 44 weighs 46000 lb this year. up from 44000 10 yrs ago. Same hull as the MT44.
If it is on its original lines, it wiill weigh in at around 40000. If stripped out, still over 35000.

The 225 may be just fine, even if too big by Fred's book. Reliability is usually more up to the owner than the engine design/brand. *A good mechanical survey will tell the tale. I can tell you from personal experience that a Perkins Sabre 225 will run all day, week after week,*at 1/3 rated fuel burn with no ill effects. So long as a low RPM is balanced by continual oil temps in the 185 - 200 range and once a week or so run at say 2000 RPM for 20 minutes without problems, all should be OK. How many hours on the engines?

Again, a good survey -----

Perkins 225

I am looking at a 38' Marine Trader with a displacement of 22000 lbs with a Perkins 225 with 2880 hrs. I am interested in running at around 5 kts & hoping for 2 gph or less fuel consumption. Any opinions on my chances?

moonchaser said:

I am looking at a 38' Marine Trader with a displacement of 22000 lbs with a Perkins 225 with 2880 hrs. I am interested in running at around 5 kts & hoping for 2 gph or less fuel consumption. Any opinions on my chances?

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At 5kts your going to be running that engine at probably under 1000rpm. Your fuel burn would be less then 1gph and the engine would be destroyed in no time as she would never get up to temperature. At 1500rpm she would burn under 1.5gph making over 7kts and the engine would last forever if cared for.

Daddyo said:

At 5kts your going to be running that engine at probably under 1000rpm. Your fuel burn would be less then 1gph and the engine would be destroyed in no time as she would never get up to temperature. At 1500rpm she would burn under 1.5gph making over 7kts and the engine would last forever if cared for.

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I would think over 7 knots optimistic for 38 feet and 1500 rpm...I have essentially the same hull form and weight but only see a bit over 6 knots at 1650 rpm or so...but I think you are right in suggesting pushing that engine a little harder.

Most displacement boats will be cheapest to operate at the square root of the LWL times .9 to 1.15 .

There is usually very little difference in burn between these speeds .

Check with the eng mfg for the lowest long term RPM restrictions.

Usually a simple look at the mfg lit will show a HP graph of some sort.

Where it starts at the lowest RPM is a good clue .