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Hey Guys...In the process of shopping for engines...If I go ahead and get either Cummins 6BTs in the 270-330 range or Cat 3116 at 300-350 HP what are the considerations I should be evaluating in deciding on choosing a 1.5 or 2/1 gear ratio. I will be slow trolling from time to time for grouper in the Bahamas so I want to make sure I am making the correct choice with or w/out trolling valves...Thanks in advance...John

John, I went with zf 220a. down angle 1.5:1 gear ratio, I did go with trolling valves. Make sure you put a BIG red light on dash so you or anyone else running boat won't smoke the gears when trolling valve is on. Hope this helps. BH

Thanks Bob

John

I have the same as Bob in my 31, with the 270 Cummins. I don't have trolling valves and on one engine I am at about 3.5 knots. Both engines close to 5 knots.

Hi There ....
Tony, with your Cummins 270s, what is your cruise RPM, what is prop size and what is your cruise speed ?
thanks

Steve

I am running 20 x 23 with a slight cup. They top out at 2650, they are rated for 2600. The Cummins dealer told me I could run them at 2400 all day long without hurting them. I usually cruise around 2200 to 2300.

As I have posted in the past, I am running light no tower or hardtop, just a soft Bimini. The RPMs basically almost tie to the knots. At 2100 I am at 21 knots at 2200 22 knots at 2300 I am a little over 23 knots and at 2400 depending on the tide I can be anywhere from 24.5 knots to 26 knots. She tops out at just shy of 30 knots.

Thanks

Thanks Tony

UV had the 250 Cummins and used to say the weight did not matter he always made the same speed. I find that as she lightens up she runs faster which makes sense. When she gets down to a half tank I find making 25 knots a piece of cake.