SailNet Community

SailNet Community (http://www.sailnet.com/forums/)
-   Helms (http://www.sailnet.com/forums/helms/)
-   -   Propeller choice for Helms 30 (http://www.sailnet.com/forums/helms/61149-propeller-choice-helms-30-a.html)

ACWbuff 01-09-2010 01:38 PM

Propeller choice for Helms 30
 
I am in the process of buying and refurbishing a 1978 Helms 30. The boat was a casualty of Hurricane Rita but came through it in fairly good shape. There are no issues with hull or rigging but the existing gasoline motor and propeller were both write offs. I am repowering the boat with a Yanmar 2GM20 diesel and I would like to hear from other Helms 30 owners (all four or five of you) about your propeller choices. The shaft size is 1 inch. Yanmar recommends a 15x11 propeller for the 2GM20 while CDI recommends a 16 inch prop. Neither recommendation is specifically for a Helms 30, which isn't listed in their tables. No surprise there.

I'm leaning towards a fixed 2 blade prop just to keep things simple but I would like to hear about whatever you've got and are happy with.

Thanks for any information you may care to impart.

Wayne25 01-10-2010 09:29 AM

ACW - Welcome to the board. I'm sorry I can't help you with your prop question directly and hope another Helms 30 owner can help.
The only thing I would recommend is to use a manufacturer/dealer that will work with you on swapping props until you dial it in at the rated rpm for WOT (wide open throttle). You don't want to damage your new engine in the long run by having the wrong prop.
Another thought to get you close would possibly look at what is used on a Catalina 30 with the same engine.

ACWbuff 01-10-2010 11:33 AM

Thanks for your suggestion
 
The Catalina idea is a good one but I'm not sure if the hull rise towards the stern is approximately the same for both boats. What I'm mainly interested in here is the clearance between the propeller shaft and the hull.

The propeller information from CDI and Yanmar was specific to the 2GM20 engine and just assumed that there would be room for the prop on whichever boat the engine was installed upon. Elsewhere I have read that for proper operation there should be about 20% of "headroom" between the arc of the prop and the hull. That would mean that CDI's 16 inch urethane prop would need 9.6 inches between the hull's bottom and the center of the propeller shaft. The 15x11 prop Yanmar recommends would need 9 inches. I've spoken to a couple of Hunter 34 owners at the marina, one with a 2QM20 and the other with a 2GM20. Both have 15 inch props on their boats and seem happy with them.

I was hopeful that someone who owned a Helms 30 could report on what worked well and what didn't from personal experience.

Wayne25 01-10-2010 11:26 PM

ACW:
When Sailnet had an email board we used this site (sailnethelms : Sail Net Helms Group) to post our pictures and data. There is info there on Helms 30 and some email addresses for the owners. Some may be dated.
Also, go to the top of this page, click on resources and scroll down to email list archives. Go to the Helms site I spoke about above and you will also find more info on Helms 30 and their owners.

Waltthesalt 01-12-2010 09:00 PM

I recommend going to Michigan Wheel. Give them your specs and info and they'll do the calculations and give you recommendations. 2 or 3 blades depends on your priorities. If the blaed diameter is limited you may have to go to 3 blades. Alternatively you can make your own calculations... use Geer's Propeller Handbook

ACWbuff 02-22-2010 03:36 PM

Temporary prop choice
 
After some correspondence with a Helms 30 owner (Alex Miller) I went with a 13x10RH propeller from Martec. That ought to get me to the yard for a bottom job. I can check clearances for some future propeller once the boat is up on stands.

Wayne25 02-22-2010 05:29 PM

Thanks for keeping us up to date. I'm glad you found another Helms 30 owner.

danzee 04-11-2011 11:15 AM

Prop Choice for the Helms 30
 
Quote:

Originally Posted by ACWbuff (Post 572665)
After some correspondence with a Helms 30 owner (Alex Miller) I went with a 13x10RH propeller from Martec. That ought to get me to the yard for a bottom job. I can check clearances for some future propeller once the boat is up on stands.

--------
I know this is an old post (I just found it). FWIW, I did a pretty through analysis after measuring clearances and taking other of the boats parameters into account, and ended up with a 15x9LH Martec elliptical prop. It has proven to be a good choice over the past 33 years for my boat with the 12HP Yanmar (YSB12).
Dan Z
danzee k2ywe mojo helms morse code psia bmw k3au


All times are GMT -4. The time now is 06:50 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012