Author Topic: High thrust props  (Read 2154 times)

Offline DougN

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High thrust props
« on: May 13, 2015, 09:17:17 AM »
I have an '82 9.9 Mariner(Yamaha)on my CP23.I was going to swap to 6hp sailpro,mainly because of the weight.I decided to keep the old motor because it has electric start,charges the battery,and can be set-up with remote controls which I eventually I plan to do to help with docking as I'm not as agile as I used to be.The dealer told me none of these features were available on the Sailpro and the old Mariner has been lightly used,runs great and has never failed to start.I hate to get rid of it so I just replaced the motor mount bracket with a more heavy duty one.It took two people to get the motor out of the water with the original mount.Would it be to my advantage to change the original prop to a high thrust prop.

Offline Vipersdad

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Re: High thrust props
« Reply #1 on: May 13, 2015, 10:30:05 AM »
The key to this is that you want to keep your engine operating at the correct RPM range.  The heavier the load the lower the pitch to keep the RPM's up.  Tohatsu has a nice chart on their site.  Here is what they have for my 3.5 Long Shaft:

Heavy Load 1,500 to 3,000 lbs.
4.5 pitch (7.4 X 4.5 prop)

Moderate Load 500 to 1,500 lbs.
5.7 pitch (7.4 X 5.7 prop)

Here is data on their 9.9 hp chart.

Heavy Load 1,500 to 3,000 lbs.
High Thrust 7 pitch (10 X 7 4-blade)
6.9 pitch (9.2 X 6.9 3-blade)

www.tohatsu.com/accessories/prop.asp

Viper
s/v  "MaryElla"   Com-Pac 19 / II  #436
Lake Winnebago, Wisconsin

Offline Jim23

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Re: High thrust props
« Reply #2 on: May 13, 2015, 11:50:24 AM »
I replaced the stock prop on my 99' 8 HP Tohatsu 2-stroke with an 8.7 Dia X 7 Pitch - 4 Blade (High Thrust) prop. Thrust in reverse is greatly improved. Here's a link to the actual prop...

http://www.boats.net/parts/detail/props/T-3B2B645120.html

Offline atrometer

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Re: High thrust props
« Reply #3 on: May 13, 2015, 05:32:31 PM »
The sailpro can be purchased w/alternator (6 W)
August Trometer
North Fort Myers, FL

Offline HeaveToo

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Re: High thrust props
« Reply #4 on: May 13, 2015, 08:17:43 PM »
I have an alternator for my outboard.  That being said, it isn't worth a thing.  It replaces very little power.

I tend to spend a bit of time out and I wanted a better charging method.  For $250 I added a 100 watt flexible solar panel with a Genasun GV-10 charge controller to my set-up.  It should generate plenty of power for me.  It is far more power than I could generate with that tiny alternator. 

I have thought of getting the high thrust prop for my Tohatsu 8 hp 2 cycle.  It does okay with what I have now but the P/O put thrust plates on it and it seems to make a difference with cavitation in waves and efficiency. 

In the picture you can see it on the outboard if you zoom in.
http://i296.photobucket.com/albums/mm199/HeaveToo/2014%20Solomons%20Island%20Trip/023_zpsf9b08f8a.jpg



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Offline Shawn

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Re: High thrust props
« Reply #5 on: May 13, 2015, 10:05:20 PM »
"The dealer told me none of these features were available on the Sailpro"

The Sailpro model comes standard with a 6amp alternator and a high thrust prop. Tohatsu makes s a SRS kit to allow for remote controls. No electric start option though.

Shawn

Offline HeaveToo

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Re: High thrust props
« Reply #6 on: May 14, 2015, 09:54:44 AM »
If it is anything like my Tohatsu it starts with minimal effort with one pull.  It impresses me.
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Offline DougN

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Re: High thrust props
« Reply #7 on: May 16, 2015, 11:27:09 PM »
Mounted a 20hp bracket today,very happy with it.Can finally get the motor up by myself.I even have to give it a little push to go down.Had to modify it quite a bit,but I knew that.Went across the street to the marina and ordered the prop.Found a Mercury that should fit,almost the same diameter and pitch as the Tahatso.The owner deals in Evinrude(same Tahatsu power head)and can be ordered set up like the Sailpro.I asked about the electric start and he just laughed.He also called it a "one-pull start".I've dealt with him and his dad for 18 years now and they've always been fair and honest.He knows my motor and my boat.His advice to me was"You WANT a new motor but you NEED a new mainsail"Being as he sells motors and not sails I think I'll take his advice.

Offline HeaveToo

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Re: High thrust props
« Reply #8 on: May 17, 2015, 10:00:34 AM »
That is probably pretty sound advice. 

It is better, in some ways, to have a pull start.  If your batteries crap out while you are on the hook you can still start the engine.  The alternator really isn't putting much power back....you are probably lucky if you get 2 amps per hour replaced when running it.

You can almost get a new jib and a new main for the cost of an outboard.  That is a comforting thought.
Døyr fe, døyr frender
Døyr sjølv det sama
men ordet om deg aldreg døyr
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Offline Shawn

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Re: High thrust props
« Reply #9 on: May 17, 2015, 11:13:58 AM »
Doug,

On my Sailpro it was always a 2 pull start. Pretty much always started on the second pull no matter if it had been running 2 hours before or 2 months before.

Heavetoo,

On smaller outboards that have electric start I think most still have the recoil starter as well. Just in case. That is a handy feature for the reason you stated.

Shawn

Offline brackish

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Re: High thrust props
« Reply #10 on: May 17, 2015, 04:49:32 PM »
Your first statement "because of the weight", is the most important and telling for me.  I had trim problems with an electric start 4 stroke 9.9.  I also had significant problems mounting and removing the motor.  Additionally I had much difficulty lifting it out of the water on the mount.  Even though it had electric start, I had to start it manually a couple of times, and it was a back breaker.

All problems solved with the Sail Pro.  Mine also starts second pull after 2 minutes of run or two months of idle time (I never, ever, run it dry or disconnect the gas line unless towing).  And those pulls are almost effortless.

I might not have made the switch if I hadn't had another home for the 9.9.  It goes on a fishing skiff.  Now that I've done the switch I think it is the best thing I've done for overall hassle reduction on the boat.


 

Offline Shawn

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Re: High thrust props
« Reply #11 on: May 18, 2015, 07:38:00 PM »
Brackish,

" I think it is the best thing I've done for overall hassle reduction on the boat."

I've considered another Sailpro, many times, after all the hours I've spent working on my "black magic" Volvo inboard.

Realistically though I'd probably get the 9.8hp 25" Tohatsu.

Shawn (With fingers crossed that all the latest work appeases the Green Demon)

Offline Damsel19

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Re: High thrust props
« Reply #12 on: March 19, 2017, 09:26:48 PM »
For years I ran a prop guard on a 6 hp Yamaha.  Proguard.net
It greatly increased thrust in fwd and reverse. I ran it with a high thrust prop.  Made yhe cp19 feel like a tug boat. And it was safer, the biggest benefit.