R29 high fuel usage. Nowhere near spec’s

[torangefree]

I just purchased a used 2010 R29 in “near pristine “ condition. The boat was professionally surveyed, gone over by a mechanic, and has 402 hours on its Yanmar 260, with a clean hull. I just brought it back to its new home in Horseshoe Bay from Nanaimo, which is a run of 31 nautical miles and my performance was as follows. It was a beautiful calm day in the Pacific Northwest with little wind and not much wave action.

7.0 knots at 2300 rpm 3.8 Gph
8.1 knots at 2550 rpms 5.0 gph
10.9 knots at 3000 rpms 7.9 gph
17.1 knots at 3950 rpms 14.1 gph - max speed

Compared with Ranger Tugs specs, and every independent review I have read this is way, way off. A big reason I bought the boat was it’s efficiency and now I’m not sure what to do?

Also at 7.2 knots the deck is so awash with water the surge of backwash so heavy the tender on davits looks like it wants to pop right off. Wasn’t this boat made for going that speed?

Averages from reviews are all in the following range

4.5 knots at 1000 rpms 0.7 gph
7.2 knots at 1750 rpms 2.0 gph
9.7 knots at 2500 rpms 4.7 gph
14 knots at 3000 rpms 7.3 gph
18 knots at 3600 rpms 9.8 gph
22.5 knots at 4000 rpms 12.7 gph - max speed

After doing all my due diligence w professionals, I am very disappointed with this performance. What could be the issue here? Slippage? Wrong Prop? I’m a newbie to this type of boat, having had only gas inboard outboards before.

 

[daveo]

It looks like your fuel use increases at the higher speeds / RPM's . Did you use the trim tabs to lift the boat?

 

[BB marine]

There are all sorts of performance data posted here on Tugnuts. My opinion on performance of the Tugs and Cuts with diesels is, if you want to get good fuel economy and a good cruise range run at hull speed. The LWL is almost true to the length of the boat giving your 29 Tug a better hull speed then a common design 29' boat. After hull speed the boats fuel economy drops. I find our C26 gets good fuel economy at 1850 rpm 6.5 KTS 4.10 mpg 1.8 gal hr. anything above that I'm better running the throttle up to 3400 rpm 13kts and 1.80 mpg 9gallons an hour. From 2500rpm to 4000 rpm MPG doesn't change. The Tugs and Cuts are Semi displacement Hulls. As far as Fluid Motion posted performance numbers. I'm not sure where they come from. I suppose, shiny bottom, no water, waste, low fuel, no gear on board, flat seas, the numbers might be close. Yes there is also a lot of dirty wake associated with this hull design. And the swim platform design is an issue at midrange speeds . Its not a bad thing just something to get use to after having a planning hull. Enjoy the 29 Tug very nice hull and design. It is my favorite Ranger Tug design. I like the pilot house Door. Good luck with your Ranger.

 

[aculverwell]

At the risk of stating the obvious-- the direction & strength of the current can also have a major impact on fuel usage. Even when the water seems calm and there are no waves, the current can still be moving your boat (and adding/subtracting speed)-- so you really need to test your fuel consumption when the current is close to slack.

 

[torangefree]

Never hurts to state the obvious, no ego here on that one. The slighty oppositional cross current (tide going out in big body of water) was not too heavy, almost no wind. I was using trim tabs at full throttle, and level tabs at the slower speeds. I would expect maybe this kind of performance headed into waves and wind, but not on relatively placid waters.

Does the performance get significantly worse than this? Someone would have said something open this forum. I must be doing something wrong.

Also mostly full fuel tank, clean bottom painted three months ago, no gear on Board, besides safety gear, and a Tender on Davits off the swim deck.

 

[BB marine]

I posted incorrect 3400 rpm 8.1 gph and 3600 rpm 9gph all equaling 1.80 mpg just faster. I don't think your doing anything wrong. You will also see slightly better averaging maintaining a steady speed for longer distances.

 

[Red Raven]

Never hurts to state the obvious, no ego here on that one. The slighty oppositional cross current (tide going out in big body of water) was not too heavy, almost no wind. I was using trim tabs at full throttle, and level tabs at the slower speeds. I would expect maybe this kind of performance headed into waves and wind, but not on relatively placid waters.

Does the performance get significantly worse than this? Someone would have said something open this forum. I must be doing something wrong.

Also mostly full fuel tank, clean bottom painted three months ago, no gear on Board, besides safety gear, and a Tender on Davits off the swim deck.

Don’t be fooled by the condition of the seas. The water can be perfectly glass and still be moving at 4 knots during maximum tide change. Your speed displayed is the speed over ground (SOG) which will be significantly impacted by the current even in a very large body of water. We often see a drop of 2-3 knots from our average with no visible sign of any current. Often the actual current is even far different than the predicted current.

At time it also benefits you as well. We were once traveling with 4 persons on board with full gear and did 23 knots WOT in President channel off Orcas Island with no “visible” sign of current! Normally I can’t get over 18 knots even with two people. Other times I am lucky to get 16knots WOT.

Having said all this, while MPG and speed will vary significantly due to current the GPH should vary much less for a given RPM (though it still does vary somewhat). It is also possible that your fuel flow meter needs calibration. When you fill up, compare the actual gallons used with the gallons used on the Garmin. You may find that you are actually using less fuel than indicated and thus all the numbers are skewed. Ours typically reads a couple of percent high. (We use a little less fuel than indicated. I like it this way!)

Curt

 

[Cutwater28GG]

Also weight on-board is a big factor. people and gear. and I second the deceptive nature of current with glassy water.
also 3 months in the water is not necessarily a clean bottom. there will likely be barnacles on the keel plate and some growth on the trim tabs if the boat has been in the water for the last 3 summer months (growth is faster in the warmer summer months)

your 7 knot figure seems to be way off - to suggest there was a current in action. even just a couple of knots against would make sense here. 2300 RPM for me is a very inefficient rev range and seems high for just 7 knots (although I have the volvo and not the yanmar but they are both 260 horse. ) around 2300 RPM would be about 8-9 knots for me. terribly inneficient as Im just making a hole in the water.

Id be interested what your speed is at 1000-1200 revs on the same journey.

Also its worth using Nautical Mile per gallon as way to measure efficiency. (the Garmin has the option to display this measurement)

I have the D4-260 in the cutwater 28.
once I'm no longer at hull speed but I am not fully on a plane the boat is less efficient than putting the throttle down and getting the boats butt out of the water. I can get NMPG down to 1.4 at 12 knots but it climbs again to 1.8 NMPG at 18 knots due to the planing efficiency. Unless a specific speed is required there is no point cruising at the middle ranges of speed. its either 1200 RPM for 6 knots or 2900-3000+ RPM for 18 knots for me.

I can easily lose 0.2 NMPG for 3 extra people on-board if I don't get the boat properly planing .

 

[BB marine]

We had a great Ranger 29 for two years with this engine and did the Great Loop in it; 10 months and nearly 6,000 miles. Our fast cruising speed was 3200 to 3400 RPM and traveled at 12 to 14, burning 8.5 to 10 gallons per hour. This Yanmar 260 is a BMW block that is well engineered and purrs.
John & Laurie Gray
Tribute, Kadey Krogen 39
Trilogy, Ranger 27
Former Ranger Tugs: Andiamo (R-29) and Laurie Ann (R-25)

This is from a different post in TugNuts. I think these are realistic numbers not close to projected fuel economy from averages from reviews . One run is not an accurate way to get fuel usage stats. As stated tides, river currents, wind, waves, ........ make a difference in your fuel economy . I believe that the numbers 12 to 14 are MPH not KTS . John and Laurie Grey did the Loop in a R29 and post here on TugNuts. Maybe reach out to them to get fuel economy that they experienced with their boat. I don't think your boat is that far off from what should be expected. If you average the good conditions with the bad conditions you will get a real number.

 

[jroyle]

Your numbers a very comparable to what we got on our 2012 R29 Classic. Not sure what you were expecting on a semi-displacement 5 ton boat??. Maybe a boat with that big stick in the middle and a sail hanging from it would have been a better choice. 😉

 

[torangefree]

Thanks for all your points of view. I took the boat out in slack tide yesterday, and the numbers were better, and a bit more encouraging. I might not had the keys back just yet. Need to take it out for a long haul then reassess.

The boat is certainly a different beast than the runabouts I grew up with. It handles well out to sea, but one definitely needs the thrusters in tight places, and one certainly doesn’t roar into the marina and stop on a dime, like the fishing boat that passed me yesterday as I was gingerly (5 knots) coming in. 😀 I’m too big for sailboats at 6’9” so no masts and booms for me anytime soon.

Talked w the guys at Ranger Tugs and they think the prop is probably tweaked, or possibly replaced with one that’s just a bit off. They also figured the tender might be dragging the stern down too much, and creating drag. I don’t have anything else out there, the tender is only 126 lbs. and anywhere between 5 and 9.1 knots the water is pulsing heavily between the six inch gap a flooding the swimdeck. At 7.2 knots the pulsing makes it look like the tender just might pop off. Anybony else run into this? Any solutions besides just leaving the tender at home or putting it up top?

Just to add to the knowledge base.

The stock propeller for an R-29 classic is an 18 x19 w 0.105 cup part# 1410B ( from Ranger Tugs)

 

[Cutwater28GG]

interesting pulsing behavior. I dont have a similar experience. my dinghy is super light though.

do you get the same pulsing behavior at various trim tab levels?

 

[BB marine]

viewtopic.php?f=2&t=10117&start=0&hilit=swim+platform#p69697

This is a Link to the subject you are talking about. At 7.5 to 8 kts I have the same issue with my C26 and many others have experienced it too. I installed Drop Fins to my trim tabs, this helped lift the transom some at 8kts but I still gets the wash on the platform.( The drop Fins really helped at higher RPM bringing the bow down)The best solution is don't run at that speed. Hull speed for economy, Cruise speed to get where you want to go, comfortable ride and the swim platform is not dragging. You will find your comfort zone after a few trips. I know exactly what you are talking about the boat handling differently. It is a different design hull from what I was accustom to. I have always had Planning Hulls mostly Searays but I have also delivered many other manufacturers boats all being planning Hulls. After the adjustment to single inboard semi-displacement hull I like it. The only part that I still have mixed emotions about is 20 kts.WOT and cruising at 13kts. All the other great amenities out way that so we are happy with the choice. Once you get familiar with the boat I think you will nor regret your choice.

I agree with the factory response. If you are a light boat without equipment and passengers and turning 3950 rpm . I personally like to see a light boat capable of operating over max RPM so when you are fully loaded you are not loading the engine down to more the 100 rpm below recommended max Rpm.