1977 Marine Trader 40

Hey folks,

New to the forum and new to trawlers.

I'm looking at a 1977 marine trader 40 double cabin. This is our first time in the market for a "livaboard size vessel".

This boat had a survey in 2014. Clearly on page 6 the survey lists the boat hull type to be semi displacement.

It has a single Lehman 120.

Am I missing something here? 30,000 pounds with 120 ponies...This boat seems like it should be a full displacement hull. Right?

My basic understanding of semi vs full is this:

On a semi the engine power is divided both between forward propulsion and lifting the bow. Semi = slightly faster cruising speed at the cost of significantly worse fuel consumption.

On a full displacement 100% of the engine power is spent on forward propulsion. Full = slower speeds but it's the most fuel efficient vessel under power aside from a sailboat.

I'm sure my understanding is elementary so any and all help is greatly appreciated.

Thanks,
Perry

You have it pretty much right, and yes, as the owner of a 34 ft boat with similar hull shape and the same engine, I can tell you there is no way I can semi-plane, so that boat won't. The description might be right re the hull shape, but you'd need twins of 300hp plus to meaningfully semi-plane in the vessel you are describing, in my view. Others may differ, but I doubt it.

I have 168hp Mercedes in mine. (single) No it doesn't plane or semi-plane but the fuel consumption is fantastic.

Wonderful. Thanks for the help! If we purchase I'll post pics for sure.

My 41' President with twin FL 120's only dreams of planing or going any faster than 8 kts. But, as Donna mentioned fuel consumption is fantastic at 3 GPH and I carry 700 gallons.