I recently purchased and took delivery of Bill Baxter’s NS30U # 507 (Persistence), and would like to join in your discussion group. Thank you for including me in the forum!
We were able to enjoy cruising, racing, and just plain getting to know the boat during the second half of the season in 2020 on Lake St. Clair Michigan. The boat is under cover for the winter, meaning planning and projects are the order of the day. One of the jobs is a propeller upgrade, from a two-blade-fixed to a folding unit. I’ll most likely be purchasing a Gori prop from ab-marine, and will need to supply them my engine output and transmission reduction ratio information. My Nonsuch Owner’s Manual information for my Universal M35V and Hurth HBW 150 is different from the Universal Service Manual for an M35, which I found online. This makes me question which information is accurate.
The Owner’s manual says I have: M-35V, 30HP @ 3200rpm, and a Hurth HBW 150 with a reduction ratio of 2.1:1
The Universal Service Manual for an M-35B says 35HP @ 3000rpm, and it shows an HBW-100 paired with the M-35B, with a ratio of 1.79:1
My question is: which set of information should I use? I am leaning toward the Owner’s Manual because it came with my boat, and should be the most accurate. But the significant difference in information tells me I should get some opinions from the veterans. Any help in this department is appreciated (as I only want to purchase one new prop).
Also, do you have a two-blade folding prop on your NS30?
If so, what size do you have and how do you like it’s performance?
What speed and rpm range do you cruise at?
My 33 has an M35 with Hurth HBW150. The reduction is 2.13:1 The horsepower is rated at 30 HP @ 3200 RPM.
Last season I stumbled upon Kiwiprop. It is inexpensive at $1500 delivered. Delivery from New Zealand was a week after placing the order. It is a feathering prop, 16" in diameter and came set at a pitch of 21 degrees.
This prop is rates low in magazine articles but I find that it works fine and it was inexpensive by comparison. Stopping power in reverse is impressive.
The drive train produces NO vibration with this setup. The Autoprop that this replaced was worn out and the vibration was noticeable.
I do run the motor at a higher RPM with this prop than with the Autoprop but I do not see that as a bad feature.
Greg: There should be a sticker on your tranny with model number and ratio. I have a Gory, and think the world of it, but don’t remember the specs. The manual that came with the boat should be correct since it’s a “V” drive.
Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA
Greg,
Here is a description that tells you were to look on the engine for the identification number. As Joe says there should be a tag on the transmission giving the model number and ratios for forward and reverse. Paul Miller has sent a picture of what the transmission tag looks like. You need to check those since they are really the only reliable source of the information for you.
"Universal Engine Identification
The model identification plate for your Universal engine will typically be located on the exhaust manifold.
Actual identification from the engine is your most reliable method."
Prop size is a mixture of science and black art. Often the prop dealers/distributors are the best source for correct sizing although they will sometimes get it wrong. You need to ask the vendor for their policy if the prop turns out to be the wrong one. Some will do an exchange. Some say you are on your own. On some props you can change the pitch.
If someone has the same boat, same engine, and same drive type (straight, V or saildrive) and the same transmission ratio their comments on prop size and pitch for the particular make of prop will be helpful. If everything is not the same the information will not be of much use. My brother and I both have 1982 26’s made a couple of months apart. They both have Beta 20 hp engines with straight drives however my transmission is 2:1 in forward and his, I believe, is 2.4:1. As a result we need different props. So comments from me to him on how my prop works will be of little value.
When I was researching props I learned that the Gori 3 blade prop comes with “Overdrive”. This lets you select one of two different pitches when you are motoring. The overdrive mode gives a higher boat speed with lower rpm. If the conditions are tough, head winds and waves you can switch the setting and not work the engine as much. The 3 blade comes with rubber stops that have to be replaced periodically. The 2 blade does not have the overdrive feature. The early 2 blade did not have the rubber stops but I don’t know if the new ones have them.
Everyone has their favorite props, usually all for good reasons.
First of all, thanks to everyone for their input. It is all helpful in one way or another.
I visited our boat, and found the engine identification plate/decal located on the engine exhaust manifold.
It matches my owner’s manual information: Universal diesel model M-35V H, serial no. 350116.
Unfortunately there is no information anywhere on the transmission other than the letters cast in the block: Hurth W:Germany.
But my owner’s manual is very specific: HBW 150 Vee drive, reduction ratio 2.1:1
I contacted Westerbeke and inquired about the difference between a Universal M35B and an M35V.
They stated there is no such thing as an M35V.
They explained that I have a plain M35, which can be seen in the chart on their website at:
They further explained the “V” is a reference to the Vee-drive transmission, not an engine model number.
The power rating in their chart for the Universal M35 matches the power rating in my owner’s manual (30hp @ 3200rpm).
So I am now confident I have an M35 engine (not M35B, etc.) with a 2.1:1 transmission, and I will use this information for propeller selection.
Thanks again to everyone. Looking forward to more interaction as we move forward!
