Efficient RPM on a 27ft 2015 Ranger Tug
- Thread starter Martin
- Start date
Red Raven
Coupeville, Wa
- Joined
- May 14, 2015
- Messages
- 1,811
- Location
- Whidbey Island, Wa
- Fluid Motion Model
- R-27 Classic
- Hull Identification Number
- FMLT2734C414
- Vessel Name
- Red Raven
- MMSI Number
- 338190767
Since you state fuel consumption I’ll just state the slower you go the more efficient for fuel. From there it gets complicated. How much time do you have? How much current or wind will you likely encounter? There is no single answer to this question. If you go 3 knots you can go a very long ways but it may be dark before you get there even with no current. If you are hitting 3 kts against you, you will never get to where you are going! So the answer is it depends on the conditions and your schedule. We often run at 7 kts with no current or wind which may result in 5 to 8 kts depending on the conditions. Of course this is when we have the time. If an arrival time is important we will run 12 or even 13 knots if necessary especially if against a 5 knot current! Take your pick, we choose to avoid speeds between 7.5 and 10kts as the speed gain vs the fuel consumption doesn’t make sense. So for us, in our 2014 R27 1900 to 2300 rpm or 3200 to 3500 rpm is usually best depending on conditions.
Rode Trip
Marine Surveyor
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- R-25 SC
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- Rode Trip
I have an R25 with Yanmar 150, so not exact but similar. I can burn 1 GPH at 6 knots, 2 GPH at 7 knots, 4.5 GPH at 8 knots, and 6.5 GPH at 10.5 knots loaded, 11.5 knots with the boat lightly loaded. The faster I'm running the more comfortable the boat handles in sloppy seas. Generally when it's calm we keep it at the 2 GPH rate, but as seas pick up or any kind of cross swell then we push her hard just for the comfort. Making the stern squat and pushing a big wake does wonders for keeping her from rolling.
tlkenyon
Well-known member
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- Sep 30, 2010
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- R-25 SC
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- 3 kayaks, 1 canoe; R-21 (Nellie May I)
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- Nellie May
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- 338219131
With your boat loaded as is typical for you, find a calm area and run thru the RPM range, recording the mileage, consumption rate, RPM and speed. Build a chart. It will be specific to your boat. Here is the chart I did for my 2015 R25sc.
scross
Well-known member
- Joined
- Jan 30, 2015
- Messages
- 2,035
- Fluid Motion Model
- C-28
- Hull Identification Number
- FMLC2831A717
- Vessel Name
- R-25 Classic - Sold
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- 367719470
Great chart. Economy to me is all MPG. In my C-28 (D4-260) anything above 2200 RPM gives you almost the same MPG. You might as well go faster when you can, you will end up with the same gallons burned at your destination.With your boat loaded as is typical for you, find a calm area and run thru the RPM range, recording the mileage, consumption rate, RPM and speed. Build a chart. It will be specific to your boat. Here is the chart I did for my 2015 R25sc.
But if you really want to stretch your fuel and don’t mind a slow, slow speed 1400 RPM or less will do that!
I try to avoid cruising RPMs between 1400 and 2600 unless there’s some other factor, like high seas, that override that rule.