Motorsailer engines Horsepower: 170 vs 400?

[skwanderer]

I'm looking at a couple of same model 44' motorsailer boats to purchase. Nearly identical in many aspects. Both have twin Perkins diesel engines, but one of the vessels has two of the 85 HP engines (model 4-236), the other vessel has two of the 200HP engines (ST6.3544m). Can anyone assist in comparing/contrasting the two power systems? And what would the motoring experience be like in each? Much difference? Costs to maintain? Valuation of the vessel difference? Thanks for any assistance and advice offered!

[David_Old_Jersey]

2 ,x 85hp sounds a lot....unless shaped like a brick! 2 x 200hp on the same hull for a motorsailer sounds seriously over engined.

The exception being if they are actually trawler yachts with sails as accessories. Or ornaments! In which case more is better.

Can you share the boat model?

Sent from my NEXUS 5 whilst sitting in my armchair tied to the dock.

[markpierce]

You don't reveal the boats' displacement, but 170 horsepower probably is more than sufficient to power the vessel. Four hundred is a waste of space.

[a64pilot]

I'm thinking twin 200's is a planing boat, or almost so anyway, unless a really large boat.

[skwanderer]

Thanks for the reples!
To follow up with answers to the questions:

1980 Lancer 44' with the combined 400hp (their asking price $75k)

1981 Lancer 44' with combined 180hp (their asking price $49k)

Displacement listed as 23,000 lbs

Any further thoughts would be appreciated

[a64pilot]

My 25,000 lb sailboat is powered by a single 40 hp Diesel if that helps, course it's cruise speed is around 7 kts. Surely 85 is sufficient, and twice 85 more than enough, and 400 is just heavy and expensive?

[skwanderer]

I realize the Lancer is more motor yacht shaped than sailboat shaped (13'9" beam), which is appealing to me. Just not sure why the vast difference in engines (and price) between the two, and what power would be sufficient.

[Jim Cate]

and what power would be sufficient.

Sufficient to do what? 170 hp is certainly enough power to push that boat to hull speed in any conditions where it would be prudent to do so. 400 is just weird!

One also wonders if the hull structure is actually capable of safely absorbing that much power? Lancers were not known for hugely strong construction IIRC, and unless the hull was built especially for that engine size by the original builder, I'd be a bit worried...

Cheers,

Jim

[a64pilot]

Most of us consider hull speed to be sufficient, however I believe the Lancer's are supposed to be capable of easily exceeding hull speed by a large margin? But somewheres about hull speed, drag goes up a lot, don't know if it's exponential or not, but say a lot.
My sailboat returns about 6.5 nm per gl of fuel at 6.5 or 7 kts or so. An equivalent displacement Sport fishing boat on plane may burn 2 gls per mile, or about 14x fuel per distance traveled, but he will get there in a third of the time, assuming he has the fuel capacity.
I believe twin 200 hp motors if the HP is used will burn a whole lot of fuel, and if it's not used, that's not good for the engine, lightly loaded Diesels will "wet stack" that is un-burnt fuel goes through the exhaust stack, un-burnt fuel among other things washes off oil from cylinder walls, dilutes oil, bad things.
http://www.plantengineering.com/indu...ca8f03440.html

Now I don't know anything about Lancers really, but 400 HP in most any kind of sailboat that size wouldn't be an asset I wouldn't think, if nothing else I think the weight would hurt performance, the "balance " of the boat and greatly reduce range and increase operating costs.
But I could be wrong, is there user group of owners that you could ask?

[skwanderer]

Hi Jim! Thanks for your response. Yes... Sufficient to do what you answered. What is IIRC, please?

Hi a64pilot, you've got some engineering chops in that answer, and articulated in a way I wan't able to do... If 170hp is capable and not underwhelming to drive her forward sufficiently safe and efficient, then what would 400hp do to everything else. Thanks much for the detailed reply re diesel efficiencies.

[Steadman Uhlich]

IIRC = If I Recall Correctly

[David_Old_Jersey]

From my quick Google the 400hp gets her up to 15 knots, cruising at 12. For a sailboat under power that is fast, and given she will not be planing that is semi-displacement speed......power used to plough through seas, not over them - not always comfortable. And eats a lot of fuel. A serious lot! Tankage of fuel and consumption will be useful to check as that equals range.

Me would hesitate to buy that power on a sailboat, unless usage was around coastal day / weekend use (leisurely sailing with capacity to get back home quick - for work etc).

Aside from that which one is best would for me come down to which one was in best condition, including engines. Especially the engines!







Sent from my NEXUS 5 whilst sitting in my armchair tied to the dock.

[gazzabo]

Those are all huge HP's I have a 22ton converted fishing boat here in NZ and cruise 2000 m a season The engine is a 1985 6BD1 Isuzu on 3 to 1 swinging a 29 by 17 3blader. I cruise at 6-7 kts at 7 lit per hour ie 1lt/nm. this is using 40hp or a bit less. Revs are 1600 which is max torque. If i push up to 2400revs I get 8.8 kts AND 18.5 lts per hour. I have more time than dollars and 150 nm in 24 hrs is great as I am an ex-sailor.Hope that helps.
As an addenda I have a mate with a 4cly LISTER water cooled JP4 and he gets over 2.5nm per litre and he has done 38,000nm including ocean passages to Aussie and New Cal and Vanuatu . Both the LISTER and my ISUZU are 6litr motors by the way. Also there is merit in over-proping or de-rating the engine. The LISTER is de-rated to 36hp (from 40) at 900rpm on 2:1 swings a 32 by22 4 blader.

[TacomaSailor]

PsychoSnail boat power calculator uses some fairly sophisticated D. Gerr formulas to determine the power needed to move a boat in still water:

Boat Speed Calculator

Sailboatdata.com show the following info:
Lancer 44 35.25' LWL Displacement 23,000 pounds Beam 13.75'
Built 1979 - 1982

Hull Speed 7.96 knots and needs 49 HP at the prop to move at that speed. Assuming the 4-236 makes 85 HP at 2800 RPM (quoted by TransAtlantic Diesels) then 49 HP at the prop comes at 2300 RPM using a cubic (2.8 is the Constant for the exponential curve) propeller curve as specified in all Perkins marine prop curve charts.

Cruising at 7 knots requires 30 HP at the prop or about 1950 RPM.

Cruising at 6.5 knots only requires 25 HP at the prop or about 1800 RPM.

If you had two engines then you'd run them slower.

That 23,000 pound displacement seems quite light and probably several tons under the actual. Our 40' Caliber is about the same D/L and is termed a middle weight cruiser and has a smaller and lighter engine and was designed 10-years after the Lancer. The factory displacement on our boat is 22,000 pounds.

In any case, a few extra tons on the Lancer only increases the required power by about 20% so using a single 4-236 would be plenty of power.

[TacomaSailor]

The ad for the Lancer 44 with twin Perkins 6.3544 shows a cruise speed of 12-knots at 2600 RPM.

The Gerr formula indicates the need for 1,989 HP at the prop to move a 23,000 pound boat with a 35' waterline at that speed which is a S/L ratio of 1.8 for a FULL DISPLACEMENT sailboat.

11 Knots requires 482 HP at the prop
10 Knots requires 185 HP
9 Knots requires 89 HP


UPDATE - A Motorboating & Sailing magazine review and test in December 1980 did find that the twin 200HP version of the Lancer 44 sailboat could achieve 15 knots under full power. They explained this by the fact that the stern underbody is a flat hull form as would be found on a semi-displacement powerboat such as a Grand Banks. Fuel burn for the sailboat was 2.2 GPH at 7.9 knots, 3.2 GPH at 10-knots, and 17 GPH at 15 knots

The magazine review shows the boat pointing at 30 to 35 degrees apparent while sailing. That is an admirable pointing angle for a modern race boat.

I have to say that the Lancer 44 was far ahead of it's time if it could motor at a S/L ratio greater than 1.8 and still point like a J-boat.

The Lancer 45 is the no mast/powerboat version of the Lancer 44 and achieved 17 knots using the same hull and engines.