2005 Honda 90 - which prop?

[Nancy and Bud]

Thanks Bob, I will leave it alone.

[Barry Rietz]

Nancy & Bud, The "bottom photo" shows the Permatrim to be in the exact position you want it, just slightly below the hull bottom. If it were any further above the hull bottom, cavitation could occur. Moving the adjustment "pin" inboard or out will allow trimming the angle of attack of the boat. Depending on your fore and aft load distribution, you need to experiment with settings. With a 13" diameter prop, you might find that "WOT" can be attained but not optimum speed. Its a trial and error situation until you realize the best settings. Try to do it in calm water!

[Nancy and Bud]

Finally got in the water.

WOT 5400 RPM

Top speed 24 MPH per Garmin GPS

Permatrim made a great difference in getting the bow down.


Smooth water with no wind.

Have 3 blade 13.25 x 15 prop that I will try next.

[Barry Rietz]

Depending on "drift, current, and wind", a GPS indication of true "speed over ground" is difficult to attain. However, "imperial experience" has produced many examples of what works best for most 22' C-Dory owners. The hydrodynamics involved in choosing the diameter and pitch of a prop are limitless. I personally try to keep engine speed to less than 75% of its rated specification. This has resulted in maintaining durability and fuel management. My suggestions are to continue experimenting giving consideration to vessel loading, and don't deviate too far from the factory standard 13.5 X 15" prop.

[Nancy and Bud]

Going to try the 13.25 x 15 prop next.

You may be confused about speed thru water and speed over ground.

GPS gives speed over ground, regardless of wind, current etc.

A paddle wheel speedometer only measures speed thru water. If I'm going downstream in the Mississippi River with a GPS it will give my actual speed over ground.

If I had a paddle wheel speedometer, it would only show speed thru water and not be able to calculate speed over ground as it doesn't measure current.

[Barry Rietz]

Let me know how the change of prop worked out. Regards the GPS matter, I had no idea it could be programmed to compensate for the variable local conditions while underway!

[thataway]

[Nancy and Bud]

Bob,

That is just where it was running. Very pleased with the performance improvements.

With a Honda 90 I may be going as fast as I can go. Dunno

Put on the 3 blade 15" prop tonight. Will try it out on the Mississippi River on Saturday near Galena, IL

[Desert Dory]

I agree with Bob. The cavitation plate (motor height) being at the surface of the water, while planning, is key, and the first thing to get dialed in. It sounds like Nancy and Bud have done that already.

I ended up having to raise my motor 2 holes before even thinking about trying a different prop.

Raising the engine also resulted in a huge improvement in steering effort since my boat has the old school teleflex cable/sheath type steering. Mine was way too stiff/hard to turn when running at speed, and much better now.

I'm currently running a 3 blade14x13 which let's me get to my engines Max rpm (5800) and a smooth water cruise of 24mph at 4600rpm getting 4.9mpg.

My other prop is a 3 blade 13.25x19. No bueno!

These were the props that came with the boat when I bought it last year.

[Nancy and Bud]

[Barry Rietz]

Since my good friend "Bob" has in this situation disagreed with my statement that "current, drift, and wind" would affect your attempt to "accurately determine top speed" using a GPS, perhaps he will explain his theory given potential adverse sea conditions as mentioned?

[Barry Rietz]

In summary; "sea state, set, drift, current, and wind preclude using GPS to accurately measure maximum speed"!

[Nancy and Bud]

[thataway]

For a run where there is significant current, the average between runs against and with the current were necessary to determine speed across the ground. In the old days, even 0.1 knot of current was accounted for in calibrating a paddle wheel log. One would make a run over a mile between fixed land based or markers which were not dependent on current and time the run. When doing predicted log races, the speed across the ground is the most important factor, to arrive at the waypoint at the predicted time. Multiple factors will determine that speed thru the water.

For example a prior owner did fuel burn curves for my current 25. They were with and against the current. For all practical purposes, I use an average. But with a flow meter, and GPS, the range is accurately available.

For most of us, the amount of current is minimal in relation to the total speed of the boat. But if one was running the passes in PNW then current becomes a very significant factor. In any case, GPS measures the speed across the bottom or land.

Lets say we have a current of 1 knot. The boat goes 30 knots at WOT. If you are getting only 18 knots at WOT--there is an issue. If you are getting 28 knots at WOT, then it may well be due to the current difference.

The post stated "Smooth water, no wind"

[Scuppers]

Just thought I would try to add some info. We just purchased our 19 Angler with an ETEC 90. When I sea tested, (in a lake) it had a very poorly maintained 3 blade aluminum prop, 13.5 x 15. It was a very nice boat setup with performance that seemed pretty clear was prop related.

I did as much research as possible, and installed a Turning Point 4 blade stainless wheel with exactly those specs, 13.5 x 15.

First time out today, pretty windy (22 gusty knots) with 1-2 foot chop. The boat ran great, easy to get on plane, I mostly cruised about 3000 RPM, I did not spend time doing much documentation, just trying to get the feel.

The trim tabs were useful to get on plane, but I pretty much raised them to neutral ASAP, I did not like the handling much with them extended, even though it did drop the bow a bit. I am thinking my trim and 4 blade brought the stern up, and the tabs were making me skate.

My biggest challenge was docking, I have sailing been in a center console skiff, which is like docking a canoe. The wind made that Dory cabin push the Angler all over the marina. I drifted too close to another boat, and while everything turned out fine, it was a wake up call. It is shallow there, and trimmed up, I could not get much rudder authority or propulsion.

Love my new boat. I read "River Horse", and got the C-dory bug. Then last year, my wife and I retired to our beach house, on the island, and ended up making a lot more foul weather trips. Our average depth is 3 feet, and in a good northern blow, we can get stranded in 12 inches of water. Low draft and weather protection!

We still have the 19' Carolina skiff, which can navigate a puddle.
I will report back after a few weeks of running.