Engine choice on Grand Banks 42

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GB is a semi-displacement hull and will plane with enough horsepower. The theoretical top-speed is infinite.

The difference is fuel burn. If it took 45 litres to get somewhere in 3 hours or 45 litres to get to the same place in one hour (sadly, its not linear) its the same thing...

The best GB42 I have seen had a single 6 cal Gardner that idled at 400 rpm and came with a drum of Brasso.
 
So far I’m seeing 7.5 to 7.7 knots at 1500 RPM with Lehman 120’s. I can get a bit over 8 knots at 1800 RPM but the engines seem happiest at 1500.
My 56,000 lb DeFever 44 with Lehman 120s goes about 7 knots at 1,600 RPM. Lasy year doing the Loop, we consumed 3.5 gallons per hour for all conditions, including generator time. That equates to 2 nautical MPH which I think is pretty good for a heavier boat.
 
I have Cat 3116 straight 6s in my 1993 GB42. I typically cruise at about 1800/2000 RPM, 70-80% rated RPM at about 10K speed. Get about 1.2 NMPG at that speed. I don’t work on the engines (only let Cat mechanics turn those wrenches) other than oil changes but I do all the other support/systems repair & maintenance with room. It’s tight sometimes, but I’m not a small guy either!!

I looked at boats with all different engines, happy with my choice as it provides good economy and engine room space. Oh, and you can’t beat the sound of a CAT engine!!!
 
dz,
What’s the power and displacement of the Cat 3116’s?
 
I don’t have the spec sheets with me (boats is in storage in Wisconsin) but if I recall, the displacement is 6.6L and 305 HP. If needed, I can pdf you the spec sheets (including fuel burn chart) when I’m visiting the boat next week. Just let me know....
 
No, not at all.... I’m my opinion they sound like an engine should sound.
 
We have the twin Lehman 135's in our 42' CHB Present Sundeck - semi-displacement. At 1800 rpm we cruise at 8.7-9.0 mph and burn about 3.5-4 gal per hour. Love those engines - as has been stated they are very easy to work on and they run fairly cool at 175 degrees consistently (especially after I installed two new water pumps:thumb:). But I did pull a bone-head issue a few weeks ago on the TN River - checked the strainer on the starboard engine, and then promptly forgot to re-open the sea-cock - burned up a brand new impeller:facepalm: But again, pretty easy to repair.
 
Those Lehman’s are proven marine engines and easy to work on. In addition they have a very favorable footprint!!!!
 
Here is another engine I have come across; British Leyland 165HP, not a turbo. Anybody out there with a pair of those? I wonder how easy it is to get parts?
 
I looked at a 36 with a Leyland. I couldn’t find a source for parts. Too bad as it was a nice boat.
 
I don’t have the spec sheets with me (boats is in storage in Wisconsin) but if I recall, the displacement is 6.6L and 305 HP. If needed, I can pdf you the spec sheets (including fuel burn chart) when I’m visiting the boat next week. Just let me know....

Thanks much dz.
 
Here is another engine I have come across; British Leyland 165HP, not a turbo. Anybody out there with a pair of those? I wonder how easy it is to get parts?

I had a GB with a British Leyland. It was a 200 hp turbo. Same engine as the 165 but with an intercooler. Removed the intercooler so I had a 165. Engine was bulletproof. Not a single hiccup in 15 years of ownership. American Diesel has the parts. Talk to Brian Smith at American Diesel for any info you could possibly want.
 
Like dz1, I have a GB 42 Classic (1994) with 3116 Cats. They are rated around 300 hp in this configuration (a small turbo). When looking to buy a boat (I was only interested in GB 42's), I saw boats with up to 475hp twins - which I thought was ridiculous - 300 hp engines were the most I wanted in a trawler that I intended to cruise at about hull speed. If I wanted to cruise at 20 kts or more, I would have bought a Sea Ray and I would't be on Trawler Forum.

We cruise at about 1600 - 1700 rpm and even there, I worry about underloading the engines. I bring them up to 2000 occasionally to "burn the carbon out." Can't imagine what damage would be done to 450-475 engines if you ran at hull speed most of the time. Contrarily, I'm not interested in the 20 - 40 gph fuel burn you'd need to run those big engines at a proper speed.

I think I've hit a sweet spot on my boat. We burn about 4-5 gph overall (including gen and the two engines) and everything seems to run happily. I'm happy to have the capability to run at 13 kts if I have too (due to weather or other trouble) but glad I don't have to do that all the time in order to keep the engines healthy.

Very glad to have the inline 6's instead of v-8's for accessibility in the engine room.
 
GB is a semi-displacement hull and will plane with enough horsepower. The theoretical top-speed is infinite.

The difference is fuel burn. If it took 45 litres to get somewhere in 3 hours or 45 litres to get to the same place in one hour (sadly, its not linear) its the same thing...

The best GB42 I have seen had a single 6 cal Gardner that idled at 400 rpm and came with a drum of Brasso.

I'm late to the discussion here, but if memory serves and the 42 Xsbank saw with a Gardner was a motoryacht, then i believe it was a boat that Tony Fleming built for himself while he was with American Marine.
 
I guess the point of my post was that the Gardner at 120 hp is adequate for the 42 GB. A single Lehman 120 was an option back in the ‘70”s for the 42
 
I guess the point of my post was that the Gardner at 120 hp is adequate for the 42 GB. A single Lehman 120 was an option back in the ‘70”s for the 42

single Lehman 120 would be a nice package in the GB,lots of room to work around it and efficient.
 
Specifically what power plant choice would be found in a 1980-90 Classic 49'?


Most likely twin Ford Lehman 120's. If repowered, then likely Ford Lehman 135's or Cummins 6BTA's or maybe a John Deere
 
Most likely twin Ford Lehman 120's. If repowered, then likely Ford Lehman 135's or Cummins 6BTA's or maybe a John Deere


Towards the 1990 end of the range they might also have Cat 3208s. The one GB49 MY locally is an early 90s build with twin 3208TAs.
 
I believe they came with whatever the original owner / dealer specified. However most if not all that I have seen of that vintage and size were 3208 TA’s.
 

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