Hi F42/5 revs

[Seastoke]

So wot should be max revs I think 3500 but what cruising revs 3000 L!!!!!!?

 

[Anders_P42]

So wot should be max revs I think 3500 but what cruising revs 3000 L!!!!!!?

If she has D6 Volvo's Max revs around 3500-3550rpm.

I cruise my D6-370 at 3000rpm because it sounds a bit more relaxed at 3K. Cruise rpm should be minimum 10% lower than what you get WOT. If you get 3500rpm that's 3150rpm. If after some mid season growth you reach 3300rpm then cruise would drop to 2970rpm, or lower.

 

[MapisM]

So wot should be max revs I think 3500 but what cruising revs 3000 L!!!!!!?

I half recall from my VP days that they recommended to not exceed max rpm minus 200 for extended periods.
But tbh, I never bought any hard rules about engine-only based ideal cruising speed.
It's important that you can actually reach the rated max rpm at wot, and of course you don't want to use WOT as your regular cruising speed anyway.
But other than that, finding the optimal cruising speed depends also on the boat, not just on her engines.
If you've got displays showing fuel burn in real time, finding the rpm/speed which gives you the best MPG (D speed aside, obviously) is a good indicator of where the hull/engines combo are performing most efficiently.

 

[Seastoke]

Thanks for replies

 

[MapisM]

Btw, I forgot to mention: if you have the possibility to fine tune the optimal MPG based on real time fuel burn, don't forget to play also with trim tabs a bit.
Some boats are more sensible to them than others (and I have no idea about how sensible the F42/5 is), but normally they do make a bit of difference.

 

[sharpness]

With your gear, fuel and water onboard, what speed do you get Seastoke for WOT and cruise revs ?
Glad the purchase went well, i do think the 42/5 is a good looking boat :encouragement:

 

[BruceK]

What he really wants to know is will he finally be able to keep up with a Formula 34PC or continue to take seconds on all the best anchorages.

BTW Roy, had a wee trimaran berth on my pontoon last week. He raised the challenge. Given the right wind he is faster than half the marina mobos. Can you imagine the humiliation!