PROPSPEED results

[captstu]

Our 2010 Ranger 25 moved from a drystack to a wet slip because rising water levels limited our ability to get under a low bridge. Just before leaving the dry stack, i rough washted the bottom paint to keep the boat clean until we could have the paint refreshed.

After relocating some batteries, I reported an improvement in top speed to abut 16.1 knots and a reduction in the minimum speed the boat was capable of plane operation to about 10 knows - down from about 12 (good) because of better weight and balance trim.

I'm sort of a sucker for impossible claims for miracle products.

During the bottom painting, I asked the yard (Murrelle Marine in Lantana, near Palm Beach) to apply Propspeed to the prop and the bottom of both trim tabs. I expected to reduce the need to clean the growth and reduce the corrosion.

I was surprised to see the Shearwater top speed go from 16.1 knots to just over 19 knots. This is over an 18% improvement. I have o way to reliably calculate the fuel consumption reduction at low cruise, but if it is anywhere near the 19% I see in top speed, I will save back the $350 during my trip to the SW Florida Rendezvous.

Next I try: ArtNaturals Moroccan Argan Oil Hair Loss Shampoo & Conditioner Set /Stu

 

[knotflying]

Next I try: ArtNaturals Moroccan Argan Oil Hair Loss Shampoo & Conditioner Set /Stu

We expect to see you at the Rendezvous a day early with all that speed you picked up and a full head of hair. :lol:

 

[captstu]

We are planning to use the extra day to stop in Boca Grande for a haircut and to drain all the extra fuel we saved out of the tank. 🙂


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796

 

[jimschu]

Hmmm !

 

[Cutwater28GG]

Did you see the same speed increase both directions of the tide/current and with identical boat load? fuel, water, people, gear and air temperature?

Im shocked by this level of this improvement!

Personally I have been frustrated at times with my cutwater performance (GPS based speed) on the puget sound even in supposed slack water conditions thinking I am down on power or hull cleanliness is to blame. In truth it was some weird local tide conditions.

 

[captstu]

Cutwater28GG: No, I did not rigorously test the speed in both directions - but I did look at several poles in the area and it was roughly slack tide - with a very slight current against me.

I'm preparing for a trip to the SW Florida Ranger get together - and will have several slack water periods between locks to hopefully establish a number better than "about 19 knots". The previous tests that showed a 0.2 knot improvement when I relocated a battery from the aft to forward compartments were more carefully done.

The only reason I even wrote it at all was to see if anyone else had similar results - the outstanding numbers I saw were in keeping with the ads - thus my reference to the miracle hair grow - since I didn't believe it was possible.

I don't have exact fuel consumption numbers to compare, but I'll try to get some on the upcoming trip to compare with others.

Remember, more than one thing happened - I relocated the two house batteries to the port side and moved the thruster battery from the aft starboard battery compartment to the forward compartment under the bunk near the windless. Thruster and house battery relocation made a significant improvement in weight and balance - about 4 "clicks" of the trim tab that were no longer needed to let the boat plane (almost) with no yaw and minimum roll.

I hope others post their numbers.

 

[Hydraulicjump]

I tried this in my 27 and was not able to get that kind of speed improvement.

Out of curiosity, did you see a noticeable change in rpm at wide open throttle? If friction is reduced that much, it should show up there too. I can track hull and prop fouling by WOT (I keep a record of this and it’s a pretty good predictor of time for a bottom scrubbing).

Keep reporting results. I am looking forward to putting this on at my next haul out. And losing ten pounds overnight with a kale cleanse.

 

[captstu]

I did not see an increase in RPM. Wide-open throttle is about 4000 RPM on my 4BY engine. I presume it would not increase even if the propeller fell off?

I cannot explain the increase in speed so I will try to duplicate. Thanks for your post.

 

[BB marine]

I did not see an increase in RPM. Wide-open throttle is about 4000 RPM on my 4BY engine. I presume it would not increase even if the propeller fell off?

I cannot explain the increase in speed so I will try to duplicate. Thanks for your post.

What you would notice is fuel efficiency increase. Although WOT rpm doesn't change , the load changes on the engine. When there is less load on a diesel it requires less fuel to operate at the same rpm. Another way to find reduced load and better efficiency is monitoring exhaust temperature. Higher temperature more load more fuel. When I make adjustments to try to add efficiency I don't really look at speed because the boats are so slow. A 10% or 15% increase in efficiency and less load doesn't always relate to speed it relates to reducing the load on the engines and fuel economy. It also helps in the longevity of the engine. Your speed numbers are remarkable I think you could outrun my 26 Cutwater :shock: . Your engine must have been running with a lot of load on it before.

 

[captstu]

With full fuel, full holding, and two weeks of fog and drink, we measured 16 knots in low wind and current. Seemed better, but within measurement error. Hard to compare since our Ranger is load sensitive.


Stuart Bell
Ranger 25: Shearwater
(561) 352-1796