E33 Props
Date: March 4, 2001
From: Denise & Mike Brennan brennand@nbnet.nb.ca
We have the same boat/engine and the manual says that the gear ratio is 2.61 and that is what I based my calculations on. The 1984 Endeavour E33 originally shipped with a 16X12 RH 2 blade prop. When we bought ours 2 years ago it had a 3 blade 14X11 RH prop on it. We were never happy with the performance under power, i.e. 5.8 knots at 3000 RPM in still water and no wind. Given a 15 knot headwind and this was reduced by a knot or more. This past winter we decided to replace the prop and I sent the identical email to about 7 propeller manufacturers in Canada and the States.
This is an excerpt from our email to them:
Here's a speed curve I did this summer in still water and no wind (Average of the 4 cardinal points):
RPM Knots
900 1.6
1250 2.6
1700 3.6
2100 4.3
2400 4.9
2700 5.4
3000 5.8
3125 5.8
3400 5.9 (Engine sounds stressed)
I top out at 3000 RPM at 5.8 knots, . In a 15 Knot wind I'm lucky to do 4 knots. There is lots of soot on the transom, needs to be cleaned weekly. Sometimes when backing into my berth, I ran the engine to 3600 for a few seconds, and the >black smoke just pours out. Engine was used 150 hours this summer and used only 1/3 litre oil. Engine sounds really good and smooth at 2750 RPM, and this is the range (2500-2800) that I would like to cruise at.
Existing prop is a nibril 3 blade fixed, 14X11RH on a 1" shaft.
OL = 33.17'
LWL = 27.5'
Beam = 11.5'
Draft = 4.5'
Disp. = 14000 lbs
Engine = Yanmar 3GMF Max hp 22.5 @ 3600RPM
Cont. = 20hp @ 3400 PRM
Gear Ratio = 2.61
Hull speed = 7.03 knots
The distance from the centre of the shaft to the hull is 9.5" (So max prop would be 16")
I would like to be able to motor at least at 6+ knots, even in a headwind. I got 5 replies, needless to say they were all different, varying from what I have now is the best and there is nothing better to 15X9, 16X10, 16X16 and another variation. I really think that there is some voodoo involved!
In either case, I visited our local Propdoc and had a long discussion with him. He advised that perhaps first I should change the pitch on my existing prop to 14X14 and then do some speed trials next summer and compare them to what I did last summer at various RPM's. This will give me some indication of what direction we need to go in. Changing the pitch was the least expensive option ($125CDN) and I have opted for this for now and will see next summer what happens. I was quoted between $625 and $2500 ($US) for a new prop, so I willing to try this for 1 more summer.
Hope this helps you. Let us know how you make out.
Date: March 4, 2001 I am not sure about the reduction gear ratio on our 1984 E33 Traces, but she has the original prop installed 16X12 RH, 2 blade, and that is what is specified in the E33 Endeavour Owners Manual, We also have a Yanmar 3GMF. Original owner put a 3 blade on but we decide to go back to the 2 blade since we do some club racing and keep the boat on a mooring. Hope this helps. Regards. Date: March 5, 2001 We did a fair bit of research this past winter on props and there is a gentleman from Vancouver who regularly post about props on alt.rec.boats who appears quite knowledgeable and what he says makes a lot of sense. We have also found a number of software programs to determine the prop size. Unfortunately, they all don't agree with each other. As I said I think there is witchcraft and voodoo involved. We are going to try our repitched prop this summer, but my gut feel is that next year we will be buying a Martec 16x14 3-blade feathering prop. Thanks for the insight.
From: John Craine jcraine@optonline.net
From: From: Denise & Mike Brennan brennand@nbnet.nb.ca
