crusing rpm's

[Sonny McBride]

What do you cruise at for max fuel economy ??
What is highest you run for gulf crossing.

[duetto]

crossing the gulfstream is entirely dependent on conditions and your tolerance for pain. we wouldn't go if it was more than 2' out of east, maybe 3' out of se, never went from ne.

[deising]

Sonny, it might depend a bit on your engines. Please consider changing your signature to list relevant info.

I have read about long-distance passages where running at 6 knots on one engine was done to yield maximum economy. Most would never do that.

Our 75HP engines run at 2400RPM for normal cruising at 7.5 kts and we burn a little less than 2.0 gals per hour.

[Sonny McBride]

Duane don't know how to change my name.
We have hull# 88 100 hp 3 blade 17" 13 degrees, just wondering what rpm others were running for long day runs.
I dont want to over reverse the yanmars.
Thanks for the reply.

[duetto]

we have 75s and run all day long at 33-3400 rpms. we've done that for 20 years. coming back from bahamas we've put in a couple of 12 hr days at those rpms.

[Sonny McBride]

Thanks
I will try tomorrow to see how low rpms I can maintain plane on.

[duetto]

with 75s, we're either a 7knt or a 13knt+ boat. in between we're just pushing water using more fuel. we have done 10 knts for tradeoff in comfort vs time to go when crossing gulf stream, but very rarely.

[gallf1]

We just did an Abacos' trip a few months ago....I cruise all day at about 3000-3200 rpm for about 10 knots (75hp engines). I had the 3blade propellers pitch reduced down to 16 x 13 to achieve the WOT rpm of 3800 at full cruising weight (as per Yanmar).

Its important for the Yanmars to run around 80% of WOT specifications to prevent carbon buildup.....you can run them at lower RPM's as long as you remember to run for about 15-20 minutes at the end of the day at 80% to clear the carbon

Running on one engine will cause you to run with the rudders turned towards the power side (increased drag) so you negate some of the economy but in a pinch it can be done

[Sonny McBride]

Thanks
We have 17" 13 degrees I will check out speed verses rpm tomorrow, running Deltaville Va to Chesapeake Va

[deising]

Just FYI, the first number is the prop diameter and the second is the pitch, both in inches. The pitch is the theoretical distance the prop would move forward in one rotation, exactly analogous to a screw thread.

[Sonny McBride]

Thanks I will try to correct it.

[Sonny McBride]

This AM I am trying to check rudder alignment, but can't find the valve.
Can anyone send me a location and picture ?

[deising]

No pic available but look in the tall locker in the starboard berth towards the inboard of the boat. On the bottom should be a removable cover (mine uses Velcro). The valve is there.

[Sonny McBride]

Thanks
I think I remember now.
At 78 I have a lot to remember.
I looked in that locker early this AM but the Admiral had it half full of clothes and I didn't dare move them.
Thanks again.
I just started to use the PDQ site and found it most helpfull.

[Sonny McBride]

New problem: The Starboard Tach fly bridge and lower helm jump, flutter or something quit, is there anything common to both I can repair or replace ?
Thanks