Prop Rotation: RH vs LH
Date: April 9, 2007
From: Bill Sloan rsloan3@tampabay.rr.com
There seems to be some conflict of info re. the props. on the E-37. I have a 1980 with the Perkins 4-108 and a Hurth trans. I was lead to believe that it takes a Right Hand prop. I see on the discussion some talk about LH and RH, what should it be?
Date: April 9, 2007
From: Paul Uhl endvr32@endeavourowners.com
Bill,
The original "Manufacturer's and Suppliers " list we have from Endeavour indicates that the original equipment for the E37 was in fact a 17 x 17 LH2BL prop:
http://endeavourowners.com/dscsn/info/list.html
I'm not sure where the RH listing is but I'd bet that the Perkins engine was supplied with different gear boxes (Hurth, Warner, etc) and that would influence what type of prop was installed.
However, in reality it doesn't matter if you have a right or left hand prop as long as the transmission is set up properly. You are correct that you don't want to put one on when the other is called for.
As for prop walk in reverse, we have a 2-blade folding prop on our boat and the prop walk has been virtually eliminated. Take a look at the folding/feathering prop discussion topic in the forum.
Fixed blades are designed to be efficient in forward and as a result work like paddle wheels in reverse. The blades on folding and feathering props are more symmetrical in both directions so they minimize the paddle wheel effect.
Date: April 9, 2007
From: Alvin Fryxell AFryxell@Washingsystems.Com
I believe that the Hurth requires a right hand prop….I have a Velvet Drive and it requires a left hand prop. I understand either way the E-37 does not back up very well. I have a three bladed 17 X 17 left hand. And it does not back up very well.
Date: April 9, 2007
From: Larry Chapman laneair1@aol.com
My Endeavour has a Perkins 4-108 with a Warner 2.5/1 transmission and a left hand 17x17 3 blade prop. For your information!
Date: April 9, 2007
From: Carl Hibbard Chgypsy@aol.com
The seller didn't want to spend the money for a prop, or had a very inept mechanic, who sold him the wrong rotation trans...... Could have been the owner purchasing off of Ebay or similar. A "good deal" probably. Who ever told you about the reduction was correct....but: What you have to remember is that probably the boat did not come with a Hurth transmission.
On E37's, or every one I know of.
The boats originally came with a Perkins 4-108, a Borg Warner velvet drive transmission, and a LH two blade prop 17 in. in dia ( I do not recall the pitch) Yes a trans is very critical about which way is forward, and by turning the linkage to allow the correct direction IS in all likely hood what blew it. It goes through an idler gear arrangement in reverse, and yes there is an effective different ratio in reverse. The biggest problem is the drop center Borg Warner. They also have/had a straight through model.
I do not know mechanically how your Hurth was set up but I'll bet you wind up getting that prop.
NOW ! The standard size of the original prop could be very wrong for the ratio of your trans. Suggest getting all of the numbers off of your engine and trans, and prop. Weight of boat, LWL,draft, and if you know any rpm figures at cruise and wot and go to something like Michigan Wheel (props), or a Prop Scan and have them determine the best size of prop. You will have to know the rotation of the trans.
The biggest single factor to this will be your rpm at wot. in neutral. Does it match up with the governed speed of the engine, on the plate of the engine. You have to have a correctly calibrated tach to do any of this correctly.
FWIW to all.
You could purchase (and still can ...used or rebuilt) a Borg warner in a LH or RH rotation. However the parts are very scarce. The E37 boat originally had LH. On Borgs you can tell by the model numbers, which information I will dig out for you if you desire.
In power boats with two engines you need the opposite rotations and you will find that they have slightly different ratios L to R. The RH drop center one is the one running through the idler.that is the most likely to break.
Apparently either direction is prone to the big back that holds in the reduction gearing can come loose, and that starts the bad stuff.
The Borg is very susceptible to water intrusion. It is a low oil pressure design. A leak in a cooler is higher pressure and will put water into the trans.
If you should decide to do your own removal for whatever reason, the Borg had two hidden bolts that came in from the engine side.
If you are going to pull any trans make sure to look closely at your drive plate, you are looking for broken (or missing) springs. The symptom is a very rhythmic noisy trans at low rpm.
Hope this information helps.
Date: April 10, 2007
From: Alvin Fryxell AFryxell@Washingsystems.Com
Well I did the same thing. I called Endeavour many years ago and received some wrong information and bought a right handed prop. It was wrong and I ran the boat wrong for a season. Later I purchased the correct prop for my velvet drive which is a 17 X 17 left handed prop. My 17 X 17 right handed prop was now a center piece for our bar. It happens but I am very happy with our new 23 bladed 17 X 17 left handed prop. The E -37 needs a 3 bladed prop
Date: April 11, 2007
From: Bill Sloan rsloan3@tampabay.rr.com
It seems that after searching I finally found our answer, you were on target, it depends on the transmission. The Perkins 4-108 has a clockwise rotation viewed from the front or counter clockwise rotation viewed from the stern. Many of the vessels came with a Borg Warner trans. With this trans. you must have a LH prop. However with the Hurth trans. you can have either a LH or RH prop. With a LH prop, forward on the trans. is in the A position and reverse B. With a RH prop the B position is forward. There are many models of the Hurth and while it is true there is a difference in the reduction gear between forward and reverse it is so small as to not make any difference. I have a brand new 17 X 16 three blade RH prop, (as per the owners manual) and have set the forward positon to B and did sea trials today and all seemed fine. Hope this helps another confused person such as me. Thanks for doing such a wonderful job on the forum. Regards
