First cruise on CD-25 Deja La

A

alainP

Member
I just got back from 10 days or so in Lake Powell, this was my maiden cruise on "deja la". The Yamaha F-150 has a 15 x 15 1/4 alu prop. During the test ride with the PO last November, with a virtually empty boat with only a 1/4 tank of gas we reached 5300 rpm at WOT. i thought that was a bit low at the time but did not give it further thought until this lake Powell trip.
The boat was now fully loaded for a two week cruise, tanks full, plus 2 5gl. jugs one for extra water the other for the Honda 2000 and kicker fuel.
I added Permatrim, the 9.8 kicker and bracket, the honda generator, the inflatable dink, fair amount of tools, more chain on the rode, 2 spare anchors, food, drinks etc..
It was obvious right away that i needed to raise the water line..
In terms of performance it was also clear I needed a different prop, the first day i would top out at 4200. After playing with the permatrim a bit and the trim tabs and with a little lesss fuel in the tank i was able in super flat water to reach 4500 rpm, still not good and my best speed was with the trim tabs all the way down, as soon as i tried to raise them a bit the speed would drop. the Permatrim was up about 30% for best speed. I was very stern heavy and felt like i needed to add weight to the bow so i did not have to rely so much on the trim tabs. Do any of you C-25 owners go through the same thing? what did you end up with prop. wise? Any insight appreciated. Alain Provost
 
Well ,for starters, a rule of thumb is 3% power loss for every 1000 ft of altitude. At Lake Powell, you're at 3600 ft, so figure 10%. Your Yamaha 150 is now a Yamaha 135, but you get that back at sea level. Also remember that Powell is fresh water which isn't as buoyant and the boat has more drag.

Also, the C-25 really slows down as you put weight on in the form of camping equipment, etc. I would assume that for Lake Powell you were loaded so you'd need a lower pitch than you have. With my Honda 150, I run a 14.6 dia by 16 pitch. When I went to Lake Powell, I could have gone with a 14 inch pitch but since it was for only a week, what the heck.

What I'm saying is that you need a lower pitch at Lake Powell due to altitude and water. If you're going to be there regularly, change props when you're there, otherwise make do.

Boris
 
We had a C Dory 25 with the 130 Honda (same block as the 115, so less torque than the 150). We started with a 15 " pitch, and had about the same experience or worse. We dropped to a 13", and it was better, still a struggle to get on a plane. I talked with Ken at Prop Gods, and he suggested an 11" pitch. We sold the boat to a C Brat who keeps it on Powell, and he has stuck with the 11".

It is very possible that the 13" pitch may be enough for you. With the 11" you are reving up fairly high still at displacement speeds. But we did get the boat up to the 5500 RPM and on a plane at 17 knots WOT.

Looks as if you got two threads going. Also posted on the other one.
 
Thanks for all that , makes sense, I will be at Sea Level in salt water in the future and most likely not back on lake Powell, so maybe i should wait and see how that compares before making a prop decision. At 4500 I was at or very near 19 knts.
Sorry for the double posting, don't know what happened.
 
The 15" should be fine for sea level. We love Powell--one of my Wife's favorite places. This time of the year is not the best. We like late Sept--the water is nice and warm, the nights cool off well. A few more thunderstorms. A lot less obnoxious houseboats, Wake board Boats and PWC! Also we like to go up the San Juan Arm--generally less boaters, and some interesting places to hike to.

Enjoy!
 
We did try to get away from the crowds but you are right, at this time of year it was near impossible. The winds started blowing pretty hard for the last 3 days and would start mid morning til late evening, made it a real challenge to anchor. Got my bow anchor stuck bad a couple times on some big rocks i suppose. Beautiful place though.
 
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