Efficiency: The Cost of Speed

To wrap up the technical side of boat selection, we have to talk about the "burn." Performance on a Ranger Tug is a tale of two hulls: the outboard-powered planing hulls that want to get up and go, and the diesel-powered semi-displacement hulls that reward you for slowing down.

One of the first things you learn as an outboard Ranger Tug owner is that there is an expensive "hump" in your fuel curve. For the outboard models (R-23, R-25, R-27), there is a range between 10 and 20 MPH where you are effectively plowing water—the bow is up, the engine is straining, and your fuel economy is at its worst. There is even a range that boats cannot maintain. Our R-25 with the stock propeller could not maintain a speed between 12 and 18 MPH. Once you get over that hump and onto a plane, the numbers improve. Even at hull speed, your efficiency isn’t great, although at idle, they will run for hours, just not get very far.

On the diesel side (R-29, R-31, R-43), the logic flips. These boats are quite happy at hull speed—roughly 8 knots—where they can sip fuel and provide the range that diesel is famous for.

Performance & Efficiency Comparison

The following table shows a comparison of fuel consumption for all the models at cruising speed as well as hull speed. For all but the R-25, figures are based on factory test reports. No such data is available for the R-25, so for that model, the computations are based on our actual real world experience in our 2024 R-25, which had the prior generation manual steering Yamaha F250. 

For the diesel boats the factory reports numbers in nautical miles and knots, while for the gasoline boats it reports in statute miles and miles per hour. The table converts it all to nautical miles and knots for ease of comparison. If your experience does not match this, convert what you have seen to nautical miles and see if it matches better.

The range is calculated with a 20% fuel reserve based on total fuel capacity. Obviously, for the boats with 150+ gallon fuel tanks, you can probably run them a little lower than that. 

The burn and speed on the R-43 reported by the factory is based on the pre-2026 R-43 with the IPS 450 engines. I expect it will improve a little with the larger IPS 500 engines as they can maintain the same speed at a lower RPM. To adjust that, I extrapolated numbers based on the factory data and the numbers provided by Volvo for the IPS 500, but they are not likely to be very accurate. Based on what the factory is saying, the twin F150 R-27 performs nearly identical to the single-engine F350. 

Feature	R-23	R-25	R-27 (single F350)	R-29	R-31	R-43 (IPS 500 estimate)
Length at Waterline (LWL)	~23.0'	~21.0'	~31.0'	~33.0'	~31.0'	~43.0'
Cruising Speed (Kts)	26.4	26.1	26.7	15.5	15.5	26.0
Cruising Fuel Burn (GPH)	11.8	13.6	15.3	10.2	10.0	29.0
Cruising Efficiency (NM/G)	1.91	1.91	1.75	1.52	1.55	0.90
Fuel Tank	80	99	150	145	180	300 (+ 30 for generator)
Cruising Range (NM) with 20% reserve	~122	~151	~210	~176	~223	~216
Hull Speed (Kts)	6.4	6.1	7.5	8.0	8.0	8.8
Hull Speed Fuel Burn (GPH)	2.1	2.0	3.1	3.9	3.7	5.0
Hull Speed Efficiency (NM/G)	3.05	3.05	2.42	2.05	2.16	1.76
Hull Speed Range (NM) with 20% reserve	~195	~242	~290	~237	~311	~422

**IPS 500 estimates extrapolated from Volvo D6-380 data and R-43 performance benchmarks.

The Model Number “Fallacy”

While looking at the efficiency table, it’s important to understand that the model number on the side of the boat (e.g., "R-25") is a marketing category, not an exact measurement of the hull’s running surface. For performance math, the number that actually matters is the Length at Waterline (LWL), shown in the table, the actual amount of boat in the water. 

The "Sweet Spot" Strategy

The Outboard Hustle (R-23, R-25, R-27)

If you are running an R-23 or R-25 with the stock propeller, you are likely going to prefer a 25–30 MPH cruise speed. At this speed, the Yamaha is in its power band and the boat is riding flat. If you try to slow down to 15 MPH to "save fuel," you'll actually burn more gallons per mile because the boat has fallen off its plane and is working much harder to push a wall of water. It also will be hard to steer, unstable, and it likely won’t even be able to maintain that speed for any length of time unless you spend a lot of time working the throttle, which will cost even more in fuel.

An aftermarket propeller, like the PowerTech SCE-5 or the much more expensive and absolutely gorgeous Sharrow will give you far better handling in that medium speed band, as well as at lower speeds. These propellers also promise better fuel efficiency overall, but at the cost of some top end speed.

The Diesel Trawl (R-29, R-31, R-43)

For diesel models, the math is different. If you take an R-31 and slow it down from its 15.5-knot cruise to an 8-knot hull speed, your range jumps from 223 NM to 311 NM. For long-distance cruisers, this "slow and steady" approach is the secret to crossing big water or remote stretches of the BC coast without range anxiety. The ride will be more comfortable and cost less.