Several questions

[capitancheers]

Hello guys i am new in the forum; i am from guadalajara mexico, i have a 41 convertible 2005, could anyone help me with some questions:

Our boat has the qsm11- m cummins 580 hp engines; for cruising speed which are the maximum rpm’s that we can go, in order not to force the engines?

At maximum rpm´s (the engines say 2300) for how much time can we navigate at those maximums rpm´s?

At the entrance to the salon there is a switch just beside the in/out sofa switch, what is it for? Not the sofa, the other one!

At the mdp, in the left hand side there is a an ambar switch that say refrigerator frezzer, but also in the rigth hand side panel there is also one green switch that says refrigerator, what is the difference between them?

Thank you

[Esquire]

Some general rules of thumb concerning rpms. It is not good to run at Max rpm for sustained periods of time, I only run at max rpm for a short period of time(less than 5 minutes) once or twice a season to make sure that things are running as they should. Not only does running at max rpm put alot of strain on the propulsion system it is a tremendous waste of fuel. As far cruising rpms go generally anywhere from 75% to 80% of max rpm is a good place to start. Some say that you can run diesels up to about 200 rpms less than max for cruising. It probably is pretty much the same either way. Your engine manual may have more specific information. Once your in the 75%-80% rpm range you just have to tweak it depending on load and sea conditions to get the best and most efficient ride.

[pdavejr]

Congrats on the purchase of your 41 I have the same boat but 2006 model. I run my rpms at 2050 rpms this is a good fuel burn rate as well as a decent cruising speed. When I had the 100 hour service done the cummins rep had an upgrade option to take my hp from 645 to 745 I opted not to do it. But i did ask why not just run the engines wide open to achieve the same speed, the mechanic said you could but only for no more then for one hour. Ive never ran it full speed for more the 2 minutes. everything in orange in you mdp is 110 everything in green in 24 volt. You cabin fridge and freeze are 110 volts. The one in green is for an optional cock-pit freezer. The switch near the sofa may control something near the rear bulkhead on the outside near the rear window I hbave 2 light red and trgular. Good luck with the boat. Dave