repower

[Marc]

I'm hoping someone out there will know.  I think I'm going to be buying a new outboard, what I'm concerned with is my motor mount on the stern of my boat.  It's of 1973 vintage but still works very good, however after contacting the manufacture to find out just how big I could go they could only tell me they were built for up to 20HP two stroke.  Does anyone know how much one of those weigh?  I want to go with the 9.5 Tohatsu, but the weight is what I'm concerned with caust I really don't want to buy another mount.  This is going on a 1973 Venture 224.  Thanks in advance.  Marc

[Frank]

The 8hp and 9hp are the same weight. As compared to a 20hp 2 stroke....both would be less.

[Grime]

Depending on the model of 9.8 hp Tohatsu the weight runs from 81 to 108# Here is a link that I have no money connection to. http://www.onlineoutboards.com/Tohatsu-9-8-hp-Outboards.html?gclid=CLri8Jb1jb4CFUoV7AoduSwAYQ

[CharlieJ]

I hope you're getting a great deal on that 9.5, cause that's much more engine than you really need on that Venture.

[Frank]

CJ...a Venture is pretty light. I'll bet my 4hp yammie would push that along nicely!!

[Captain Smollett]

I hope you're getting a great deal on that 9.5, cause that's much more engine than you really need on that Venture.

Good place to drop this link:

http://sailfar.net/forum/index.php?topic=1533.0

As for weight, just to add another couple of data points.  My 8 HP Johnson Sailmaster is about 85 lb (ultra long shaft, 25") and 6 HP Johnson SeaHorse Long Shaft is about 60 lb or so.  Both are two strokes.

My 2.5 HP Suzuki four stroke is 30 lbs.   ;D  Nice for carting it around, by the way!

[Grime]

I had a 6 on my Starwind 22 and it pushed her along really good.

[CharlieJ]

CJ...a Venture is pretty light. I'll bet my 4hp yammie would push that along nicely!!

That's what I used on Necessity. Hit hull speed at 1/2 throttle. Necessity is about as heavy as the Venture, maybe more.

[CharlieJ]

I hope you're getting a great deal on that 9.5, cause that's much more engine than you really need on that Venture.

Good place to drop this link:

http://sailfar.net/forum/index.php?topic=1533.0

As for weight, just to add another couple of data points.  My 8 HP Johnson Sailmaster is about 85 lb (ultra long shaft, 25") and 6 HP Johnson SeaHorse Long Shaft is about 60 lb or so.  Both are two strokes.

My 2.5 HP Suzuki four stroke is 30 lbs.   ;D  Nice for carting it around, by the way!

Oh man did THAT thread have some long unseen names on it.. Wonder where some of those folks went.

Oh, and I'm still running that 8 HP Yamaha in Tehani, after all these miles :D

[Marc]

Thanks for all the replys!!!  Maybe I am making a mistake with the 9.5.  But, I'm hoping to be able to take the great loop route and I thought the extra horsepower would help.  I'm looking at the 25" shaft.  I also have been eyeing the 6HP Sailmaster has it also is in the 25" range.  Do you guys really think that it would be big enough for going a little bit upstream on the Ohio river (I think), then I would probably get the 6.  It's a lot less money.  Yes I'm going through online outboards.  Also, would the 6 be big enough for the ICW?  Marc

[Captain Smollett]

Do you guys really think that it would be big enough for going a little bit upstream on the Ohio river (I think),

Marc, the important point to remember is "hull speed through the water is hull speed through the water."  If the water itself is moving, your speed over ground will be bigger or smaller, but you cannot change the basic fact that the limit on boat speed is water resistance.

This is even technically true for planing hulls, it's just that they tend to move so much faster than the water is moving that it is often ignored.  Not always, though; if you've ever seen those videos of jet skis or power boats on a white water river, you know what I mean.

So, if you want to answer the question for yourself without guessing, find the engine that propels your boat at "hull speed" on flat water that also fits your weight, fuel consumption and shaft length requirements.

If a 4 HP will push your boat at hull speed on non-moving water, it will do so in a current.  If a 9 HP WON'T push your boat faster than "hull speed" on flat water, then it won't go any faster in a current.  Neither will push your boat to 'hull speed' over the ground against an adverse current, but they will fail to do so by the same amount (the current speed).

I put hull speed in quotes because it's not a rigorous, sharp cut off, but that's a complication.  Also, all of this is a SLIGHT oversimplification, but the little details tend to wash out to 'neutral' over time.

See if you can borrow a 4 HP or 6 HP outboard and do some trials before you buy.  KNOW what performance you are getting on YOUR BOAT.  Trial speed (through the water) vs throttle settings and fuel consumption (if you can) and make an informed decision.

It's my guess that 9+ HP is far overkill for your boat. A 9 HP engine way heavier than it needs to be (which will hurt sailing performance by adversely affecting trim) and will not get you upriver any faster.

Final thought: what do you do if you cannot trial without some current present?  Answer:  Go both ways split the difference.  Head straight upstream for part 1 of the trail, then straight down for part 2.  Then you can use GPS to measure speed over ground and 'average out' the current speed (assuming it does not change during the trial...etc).

Hope this helps.

[CharlieJ]

Well, never having been on that river, I can't really say, BUT- I CAN tell you that my 8 HP pushed Tehani ( at a loaded weight of about 7800 pounds) against this still running at just over 1/2 throttle (JUST past the "start" setting on the engine tiller. I was only making 1 mph, but WOT would not have done any more.

Hull speed is hull speed on a displacement boat. a 5.5 knot boat, against a 5 knot current MIGHT make 1.0 with enough power. But most likely you'll have .5 .Understand we aren't talking planing here.

Edited to add- this pic was in South Carolina, where the tides can run 9- 11 feet, but more usually 7-9  feet, twice a day. :o


So, yes, from my experience, I'd say that long shaft 6 would do fine-AND be lighter.

[Grime]

I had the Sailpro on my Starwind 22. We did the ICW from Port Lavaca, Tx to NOLA. We crossed the Mississippi twice without any problems. Bucked some strong head winds and current in Galveston Bay and she just pushed right on like it was nothing. Got around 18 miles per gallon on fuel.

We wish we still had the boat. Made the mistake and sold her.

[w00dy]

Don't have too much to add, except that we also had the 6hp Sail Pro on our 26' #8000 sailboat. I thought it was the perfect outboard for the purpose. We motored portions of the ICW from TX to FL and back, and never had an issue that a bigger motor would have solved. The long shaft is pretty important to help keep your propellor in the water when the boat is pitching through the waves. Also, it's important to consider the impact of the weight on your motor mount, but also how it will affect the trim of the boat. Too much weight suspended aft could raise your bow up and adversely affect sailing performance. Now, if you had one of these, it might make sense to put a big outboard on the back:



But unless your sail boat was designed as a planing hull, that 9hp is probably just wasted space, weight, fuel, and money, assuming you don't have another boat you were planning on sharing the outboard with.

Oh, also, the Sailpro has a different prop that's designed for higher low-end torque than the regular outboard line. Food for thought.

[Marc]

Thanks to everyone who commented on my dilemma.  The decision has been made, I just ordered a Tohatsu 6 with the 25" shaft.  Should be in my hands by Thursday, whew I'm glad that out of the way lol.  Thanks again, Marc

[Adodero]

FWIW we had a 6 hp Tohatsu Sail Pro on an 8000lb 27ft boat and it pushed the boat along fine at less than 30% power, we probably had 150+ hours with it.