Camano 31 propeller size, etc.

[NCheaven]

My 2005 Camano came with what I'm guessing is the original prop, 4 blade 20"x18", very good but slightly below perfect leading edge condition, no cupping visible to my eye. It works well, and my peak WOT RPM (10 minutes near the end of longer runs) is 3800 with pretty full water and fuel and prop-coated, which I think is 100 below spec WOT for the TAMD41 P-A of 3900. I'm very satisfied with that.

But, I wonder if any Camano 31 owners (especially with TAMD41 P-A equiped Troll models, which I guess is 80% of us) have used a different size prop, or re-pitched. Has anyone experimented with cupped props or something other than 4 blades? Performance outcomes? Thoughts on best brands, best values? I'm planning to use the original for a spare, have it rehabilitated, buy a new prop.

Do most folks use prop-coat or another anti-fouling paint on their props and bow thrusters? (My bow thruster was awful after 18 months, while hull was close to barnacle-free last year....brackish water. Double coated with prop-coat April 2018....we'll see how that worked this summer. What works best?

I truly appreciate all the great suggestions I read on TF, including solutions to problems I don't even have (yet....you know what's coming if I don't say "yet".....).

 

[bayview]

I have had goof looking props redone by a prop scan shop with very positive results I would start there then decide if you want a spare prop. You have lots of other stuff to spend money on rather than a spare prop to carry around.

 

[Heron]

Alex....

I have the exact same motor in my Cape Dory 28 and achieve the Same RPM's. Based on specs, and a propscan this is as close to perfect as you'll get. I have a 4 blade 18x17, repitched from an 18x18 some years ago. Thje ability to achieve Max rated RPM at WOT is what you want to shoot for. I doubt over or underpropping at this point would get you anything. I wouldn't mess with it. Chances of you ever damaging a prop on that boat are slim...
Since I'm one dock over from you, I can confirm the bad build up last year due to water conditions. My Bow thruster aperture was also almost completely blocked, most of it occurring last summer with the Mussel problem. My hull was very clean after 2 seasons, and my Prop, with a cheap spray coat of rustoleum Zinc coating was virtually perfect. Based on those results, I did the same when hauled last spring. I have contracted with our local diver (Catfish) to give me a scrub and assess things. I expect it will be a month or so before he gets to it. I'll let you know how that goes.. Since we are in the same waters in Cypress Landing, this should tell the tale..

 

[NCheaven]

I have followed the good advice from both of you. Catfish has done a nice job on the boat several times, and last fall I got 14.4 kt @3750 rpm (WOT), 2 people, 3/4 fuel and water. Interestingly, I ran across a reference to Victoria Propellers, LTD., and their propeller calculator with input of 10,000 pounds, 200 hp, 1 bearing, target WOT of 3900, 3.3' draft, 10' waterline beam, 27' LWL, and "target speed" of 15kt. called for a max speed of 14.77 kt, using 191 hp at the prop, needing 198 hp at the prop to achieve 15kt. That's amazingly close!

It calculated 6.96 kt as Camano's hull speed, using 21.8 HP at the propeller. I think of 6.5 kt as a very efficient speed, as the flow scan number move up fairly quickly after that, and 6.8 kt seems to be a still efficient "happy place" for trips down river if there is no hurry, also close to their calculated hull speed.

The calculator said that the right prop would be a 4 blade, 20.4" by 15.4", also noting that a variance of 1" in diameter is offset by about 1.5" to 2" in pitch. Cutting back their recommendation of a 20.4" diameter to 20", using the 2.0x offset ratio would be balanced by a .8" increase in pitch, raising the Camano pitch to 16.6" - compared to my 20"x18"L prop. Difference in WOT - 3900 used in the calculation vs my 3750 after Catfish hull cleaning, difference in top speed - 14.77 kt calculated, vs. 14.4 kt actual.

What the calculation showed is, as both of you indicated, my 20"x18L" prop is one I should be pretty happy with!

Thanks for your input. We'll see how the prop looks when I haul out for bottom paint this spring.

 

[Chrisaensing]

The ATTACHED was with my boat when I got it

 

[NCheaven]

Thanks for detailed prop analysis!

That report is great info, and affirms that my prop is in the right ball park.

May Haulout showed a pretty clean hull and prop after Catfish's work late last summer. With the information I received from TF members, I'm satisfied that I have a a good prop for the Camano, and that I don't need to change specs. The yard affirmed that the prop is in good shape - clear when I saw it when hauled and in the pictures before and after bottom/prop sanding and paint.

Thanks to all participants for their input. I hope your accumulated data, experience and wisdom on this topic is useful to other Camano owners, as well.

Alex