I have twin Cummins 6BTA, 332 HP twin engines on board that were installed about two years ago. Overall I am very happy with these engines and highly recommend them. Being computer controlled, they are quieter, more efficient and cleaner burning than were the old B series engines that they replaced. The valve timing and fuel metering is computer controlled.
As donradcliffe says, you probably don't need the turbocharged versions of that engine. If your boat is a full displacement
boat and it is reaching hull speed
with the old engine then the additional horsepower is a waste of money
in terms of not only engine cost but a beefier transmission
, possible larger diameter propeller
shaft, larger propeller and fuel consumption.
Amongst the B series engines, there are 7 different marine
versions each with a different horsepower rating. For a cruising yacht, I would go without the turbo/intercooler versions if you have that choice....for the sake of simplicity and user serviceability.
Have you consulted someone or ran the numbers yourself for what would be the maximum practical horsepower for your boat? I would start there first before making any other decisions.
Also, get the Walker Airsep's (which allows the engine to burn crankcase blowby which is filled with atomized oil) and a dual Racor fuel filter
system, which allows you to change fuel filters by moving a handle, eliminating the necessity to bleed the fuel system. Both are very much worth the price
Get the "SmartSystem"...it gives you lots of good engine information such as fuel flow, total fuel burned and other important information like transmission oil
temperature and pressure. If you interface your GPS NMEA
out to the SmartSystem it will give you fuel burned per mile.
Also, with this engine, when you turn the key to Run before pushing the Start button, you will hear an electric fuel pump
come on before you start the engine...which is a really nice thing to have if your engine ever loses its fuel prime.
I added a shunt to the positive side of the alternator
so I could see how much current it is producing. Don't let anyone tell you that you cant do this...(as I was told). If you add a "shunt shifter", made by Blue Seas, then you can read the output of the alternator(s). It really helps at times to know how hard they are working. Put your alternators voltage sensor on the battery
side of the shunt to compensate for the small voltage drop across the shunt but not on the battery
side of the alternator
BTW, if anyone else with twin engines is interested, the load on the alternators balance out very well without adding any fancy electronics
to control the alternator field current....its usually within 5 amps of being equal. If you do have a large imbalance then Balmar
sells a system that corrects a large difference.