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-   -   High Thrust Prop for Tohatsu 9.9 on Nonsuch 22 (http://www.sailnet.com/forums/gear-maintenance/97156-high-thrust-prop-tohatsu-9-9-nonsuch-22-a.html)

ns22simple 03-01-2013 05:22 PM

High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
I have a Nonsuch 22 sailboat (+/- 4,900lb) with a 1994 Tohatsu 9.9 EPL (Longshaft/2 Stroke) with a factory #8 3 blade prop (9.2" D X 7.8"P)

I desire to upgrade to a 4 blade high thrust prop. I feel there is too much slip with the stock 3 blade prop.

My first choice is the Tohatsu 4 blade 10"DX7"P high thrust (Part#3ZOB645143)

I am also aware that Solas offers two 4 blade high thrust props for this motor:
- 10"DX7"P (Part#5113-100-07)
- 10"DX5"P (Part#5113-100-05)

My first choice would be the Tohatsu.

Any advice would be appreciated.

NS22 "Simple"

tommays 03-01-2013 06:07 PM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
Well its kind of a giant motor on a 22' boat


SO There all gonna slip a LOT at 5 to 6 knots :)

The question is what you hope to gain as the 7" or 5" will certainly allow the motor to develop much more thrust at the cost of much more RPM which could be good or bad depending on what RPM you make now

ns22simple 03-02-2013 01:19 PM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
By using a high thrust prop such as the Tohatsu 10"Dx7"P I was hoping to gain efficiency (more thrust at lower rpm) and do a better job of matching the motor to the hull speed of my boat (max. 6 knots).

Also by using a 4 bladed/elephant ear prop that almost no rake in the blades I believe I would relaize more thrust/control when the motor is switched to reverse.

Most outboards I see as auxillary motors on sailboats are "high thrust' variations with four bladed props that have have a ptich between 5 to 7 inches.

Thanks
"Simple"

Watercolor 03-02-2013 01:35 PM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
It seems you might gain a little when heading into the wind or current, but loose speed in the reverse conditions .

Not a topic I know much about. However, there's a company called Piranha Propellers that makes high quality non-metal props. I've heard some good things about them, but haven't used them.. However, I believe the blades are changeable. Might be worth a call and chat.

they're on the web.

Fair winds

tommays 03-02-2013 02:49 PM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
Again without knowing your current performance ?

The 5 is certainly going to be to small

dabnis 03-02-2013 04:24 PM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
I have the 7" pitch 3 blade on my Tohatsu 6HP 4 stroke. I change from the stock 9" pitch (I think) prop to slow down the trolling speed. It also increased my top speed by .5 MPH. I think the 5" pitch might put you into the rev limiter, if it has one.

Paul T

pvanv1 03-03-2013 08:00 AM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
Simple,

You are 100% 0n the right track!

The special 4-blade HT props for both the 8/9.8 and the 9.9/15 are fantastic for sail applications. They have 2 major characteristics that make them the best choice: 1. Huge blade area, combined with low pitch make them "shovel" water at low speeds. Also, 2: The over-sized hub allows the exhaust to stay off the blades when in Reverse, so the motor "bites" into clean water, giving Stellar reverse control. We install a lot of them, and have had Zero complaints -- all compliments! For your boat and motor combination, I would recommend the Tohatsu/Nissan 3Z0B645143, PROPELLER (7) 4 BLADE X 10 X 7 (F15/20C), which has an MSRP of $122.58, available from any Tohatsu/Nissan dealer (including me). FWIW, I personally have one of these type props, in 5-pitch, on the 9.8 on my 7,000-pound HR-28, and it out-performs the old 15 hp OMC motor that had a 3-blade prop. You can drop me an email at the office:paul@obersheimersails.com, or call 716-877-8221 M-F 9-5, and we can discuss the situation.

Watercolor 03-03-2013 12:31 PM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
What other engine certifications do you have? Lot of people doing the Great Loop might be interested.

Fair winds

pvanv1 03-04-2013 06:20 AM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
Quote:

Originally Posted by tommays (Post 997404)
Again without knowing your current performance ?

The 5 is certainly going to be to small

Nope. Probably allow the motor to go right up to 6000 rpm though. The prop has 4 EE (elephant ear) blades. However, the 7 would be a better choice, and is the prop the factory recommends for that application,

pvanv1 03-04-2013 06:22 AM

Re: High Thrust Prop for Tohatsu 9.9 on Nonsuch 22
 
Quote:

Originally Posted by dabnis (Post 997433)
I have the 7" pitch 3 blade on my Tohatsu 6HP 4 stroke. I change from the stock 9" pitch (I think) prop to slow down the trolling speed. It also increased my top speed by .5 MPH. I think the 5" pitch might put you into the rev limiter, if it has one.

Paul T

Completely different animal. the 4-blade prop for the 8.8 absolutely shovels water at slow speeds. Still the 7 pitch would be the best choice for that boat.


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