43 DC cruising speed

[micky]

What would be the cruising speed of a 1974 43 DC non flying-bridge with twin 6-71 Detroit at about 2000-2100 rpm?? Thanks

 

[spartonboat1]

If I run my 43' DCFB at 2000-2100, that would be about 12.1-12.5kts GPS. However, I would consider that "lugging", as the recommended cruise for these, if you have the J&T 310hp units is 2,300rpm with max rpm of 2,500. Since I have never seen more that 2,450rpm balls to the wall, I would never run more than 200 rpm under the max achieved, which would be 2,250.

However, for years I had a temp creep on my RH engine, if I ran at more than 2,150, so that is where I ran at 12.7kts. This year I reconfigured and replaced bad or kinked hoses and was able to run at 2,200rpm with "normal" temps, without the creep. I was seeing 13.8kts gps (which surprised me!) at 2,200 in flat calm southbound on Lk MI. That's with a clean hull, newly splashed, with full fuel tanks and no fresh water aboard and empty black water tanks. There is a certain southbound current on Lk MI, so don't know if that added to my SOG speed or not.

 

[Canuck Dennis]

Maxed at 14.2 with 6-71 310 hp. 2250 rpm..

 

[Bill Allen]

ABout the same with my 73' of course I just can't accept the fuel burn. Bill

 

[Jaxfishgyd]

When I seatrialed our 43 in 2000, it hit 18 kts at 2450 rpm, 15 kts at 2150rpm. That was with the boat empty. I cruise at.1100 which is a 8kt cruise. Plus we now have 35 tons of "stuff" onboard.....

 

[Bill Allen]

Only 35 tons, I guess i better unload some stuff. Looked at my sea trial when I bought the boat and it was about the same. But like you said once it got fater things change. Bill

 

[micky]

What's the fuel consumption at 2000-2100 rpm???

 

[gbharrington]

21 kts @2600 , fully furnished, half tanks and 4 people. Cummins 340hp 903's though.

 

[TROUBLE]

I have 8-53 naturals in my 72 43dc. At 1500 rpms i run 7.5 to 9 knots at 2500 rpms i run 14 to 15 knots

Art

 

[Bill Allen]

Last I checked at cruise 14kts get about .6 (thats point six) mpg, at hull speed maybe 7-8 kts close to 2 mpg (nautical mpg). All numbers vary depending on current etc. Bill

 

[spartonboat1]

Last I checked at cruise 14kts get about .6 (thats point six) mpg, at hull speed maybe 7-8 kts close to 2 mpg (nautical mpg). All numbers vary depending on current etc. Bill

I always thought I got .7mpg (nautical) at 2,150; due to a lot of slower speeds, my overall was about 1.5mpg. During my recent 2 days cruise of 8hrs/day, I ran at 2,195-2,200 and if my tanks had been filled to full, before the run (may or may not have been), the day one mpg was about 0.5, which I thought a little low. This is based on the fuel fill at the end of Day One.

I have not yet checked the fuel usage for day two.

 

[Bill Allen]

Really sounds about right adding in current, tankage etc, Thats why you'll see me doing my 7kts. Two strokes can get a tad thirsty pushing 18 tons of boat. Bill