Folding Props
Date: February 2, 1999 12:41:07 PM
From: Bill Strauss wstrauss@frbchi.orgI have an E-38 center cockpit boat and after attending this past weekends strictly sail show in chicago i am seriously considering adding a feathering prop. i am interested in several things from our knowledgable group of endeavour owners who have added a feathering prop.
- what kind of speed improvement have you noticed?
- what brand would you recommend - I am leaning towards max-prop
- if you have installed a feathering prop on an e-38 cc with the 40/44 hp yanmar engine, which size and pitch did you go with?
Thank you all
Date: February 12, 1999
From: Bruce & Moana Bonbright HaleMoana@aol.comBill, I have an E-38 and just replaced my prop, but with another 3 bladed fixed model. If you wind up installing a folding prop, I'd be very interested in learning about how well it works for you. Best Wishes.
Date: May 4, 1999
From: Bill Strauss wstrauss@frbchi.orgI did purchase and had installed by my local boatyard a Max-Prop V.P. (variable pitch). The variable pitch allows adjustment to the pitch externally (without having to haul the boat and disassemble the prop). This is a good thing because having just launched the boat the rpm on the engine is too low, (I am getting the same rpm that was too low with the old 17 x 13 prop) even though I lowered the pitch on the new prop compared with the old one. I will lower the pitch even further when I get a chance to dive on the prop. Water is still a bit cool in Lake Michigan. I called Max-Prop and they said that their prop is probably more efficient than the one that was on the boat, which would explain why a lower pitch setting (11.6") has the max rpm at the same level as the old prop (13"). I will keep the group informed on the pitch setting that brings the rpm up to the specified max rpm setting for the engine and the improved sailing performance once I get the boat ready for sailing.
Date: March 19, 2003
From: Don Kirkwood don_kirkwood@dynastart.comI have been thinking of replacing my old 3-blade prop with an Autoprop. The manufacturer recommends an 18" prop for the Yanmar 44, which is supported by prop theory in Nigel Calder's Cruisers' Manual.
Problem: the 18" prop won't fit on the E38CC - it will foul the hull while folding. In fact even the existing 17" prop doesn't have enough clearance from the hull (1" vs 1.7" required).
Has anyone else had this kind of problem? Is it possible or risky to extend the shaft or instal a longer shaft?
Date: March 20, 2003
From: Paul Uhl endvr32@endeavourowners.comDon,
I was looking at feathering props at the Strictly Sail show here in Chicago for our E32. I spoke with the big manufacturers of folding and feathering props and learned this.
- They are more limited in prop sizing than fixed blades, however if you look at a prop where you can adjust the pitch (ie: feathering prop), you can probably compensate for the loss in diameter.
- As for lengthening the shaft you have 2 big concerns. First the prop has a maximum distance it can be from the strut (1" on our E32 I believe), and second, if we purchase a folding prop you need to watch the distance from the tip of the folded blades to the rudder.
I'd explain the problem to the prop company and see what they have to say. Beyond that I'm by no means an expert so I'm going to stop here. If you find the solution, please let me know because I have a similar issue.
Our E32 has a 16x12 2-blade that only has 1/4" clearance. I've been looking at feathering props and they want to size me down to 15" but the blade surface area is smaller. Coupled with the reduction in diameter AND the fact that it's a less efficient prop, I'm concerned that I'll be under propped and still not have enough clearance (theoretically at 3/4").
Date: March 20, 2003
From: Thomas Silva shamrock@fwi.comDear Don,
In the spring of 2001 I replaced my three blade fixed prop with an 18" autoprop, as recomended by the manufactuer. I did not have any problem with the clearance from the tip of the blades to the deadwood of the hull. I also have a Yanmar 4 JHE 44 Hp engine with a 1-1/2" shaft.( NOTE) My boat has a vee shape strut, and the shaft was too long from the rear of the strut to the front of the Autoprop(51/4"). So we had to cut the shaft 2-3/4"shorter to eliminate shaft vibration when applying rapid full throttle either forward or reverse, (such as when trying to unlodge from a grouding etc. ) It was suggested by Autoprop that the distance described should not exceed 2". I might suggest that you contact: Steven Armitage with A B Marine Inc., P O Box 6104, Middletown, RI, 02842 Steve will make up a cardboard template that you can fit up to your shaft to check the fit to your boat. Our Autoprop performed as advertised. I did get better speed when motoring 7k at 2,275 rpm and sailing too 3/4 to 1k, it vastly improved our backing ability on crabbing to port as with a fixed prop. Good Luck its expensive, but I think worth it.
Date: March 20, 2003
From: Don Kirkwood don_kirkwood@dynastart.comTom,
Thanks for the advice. I have traded several calls, faxes and emails with Steve Armitage and that's the reason for my note to the web. Basically he said that teh Autoprop won't fit my boat.It seems we have very different prop locations. My shaft has no strut at all and the shaft is only 1-1/4" dia. The cutlass bearing in the hull is the only bearing. Then 3" of shaft before the prop, which is a 17" x 16" 3 blade. The proper prop for the engine is 18" x 12". I can't get more than max 2900 rpm so the 16" pitch is doing something it shouldn't.
My E38 is a 1988 model - what is yours?. In order to put in an Autoprop I could, I suppose, replace the shaft and add a strut. This would add a lot of money to an expensive prop! Any other thoughts?
Date: March 21, 2003
From: Paul Uhl endvr32@endeavourowners.comTom,
You may want to look at a feathering prop. Assuming that you'll be sailing most of the time the AutoProp may be overkill since the variable pitch concept is focused on powering. The feathering prop will give you less drag when sailing and in a 3-blade configuration may give you the proper sizing for your engine at the diameter you need to work with. It will also virtually eliminate any prop walk in reverse. May be worth looking into.