normal speed & temperature R 27

[GM Turtle]

Hi. We just got our "new to us" 2014 R27 & realize there is a lot to learn. What is the best, normal cruising speed most of you run at for fuel economy, etc? What is the normal engine temperature on the Volvo D-3 - we noticed it raised from 170 to 180 as we picked up speed. Is this normal? Thanks so much!

 

[Red Raven]

As far as speed goes there is no “normal”. It is just personal preference. If your emphasis is fuel economy and minimal noise and stress the slower the better. If you care about time as well the faster you go. As you get up to a semi-plane the boat gets more efficient in terms of speed vs fuel consumption (i.e, a 10% increase in speed results in less than a 10% increase in fuel consumption). Above about 12 knots we get pretty close to 2mpg at any speed. So, for us, if we need to go above 9 knots or so we typically run all the way up to 15 knots. When going from 9 to 12 knots the fuel consumption drops more than the speed gained. The bow also sits high with the stern in a hole at those speeds. It does usually make sense to run in that range. If we don’t need to travel far we will run as slow as 6 knots if time allows. Extremely quiet and pleasurable st that speed but it takes a long time to get anywhere.

The Volvo Penta engineer at the Maple Bay Cruise this year recommended to run WOT now and then for up to 10% of the time to check for proper operation (temperature, oil pressure, and WOT rpm). He said a continuous cruise speed of 85% was recommended. Our preferred cruise is 3500 (a bit over 85% but it just seems to like it better) and he said it was totally fine. The operators manual just states that fuel economy may be reduced at more than 90% of WOT.

The temperatures you state are entirely normal. At 3500 we are at about 185 F and 85 psi. At WOT (4000 rpm) we are at about 190 F and 90 psi. This is all only relevant to a R27 with a Volvo D3-200.

Curt

 

[Retirement Dream]

Welcome to the wonderful world of R27s. Mine is a 2015 model. It tends to like to run at about 3000 rpm. Speed varies a lot at that rpm depending on the condition of the ocean at the time. On smooth water (we don't get that very often in Monterey Bay) Retirement Dream will run about 10 knots. In our usual 4' - 5' swells that speed can come down to as little as 6 knots depending on the direction of the swells.

I don't watch miles per gallon. I do keep a pretty close eye on the gallons per hour readout on the Garmin display. At 3000 rpm I seem to use about 2.0 - 2.3 gallons of diesel per hour. With prices of diesel being what they are, that is costing me about $7.50 per hour and gives me a range of about 90 - 100 hours. I can live with both of those numbers.

I don't watch the temperature or oil pressure gauges closely either. I have noticed that the temperature gauge reads about mid-range at anything up to 3000 rpm but very quickly goes to red line if I go up above 3300 rpm for more than 10 minutes or so. Others have suggested there may be a blockage in my cooling system that causes this but I haven't taken the time to go looking for the blockage yet.

I wish you many happy hours of boating.
Scott