# minimum size outboard motor?



## Bluejacket7377 (Mar 23, 2018)

Hi,

This posting in requesting information about the minimum size needed for an auxiliary outboard motor. 

I sail a Bayliner Buccaneer 210 from a wet slip at a sailing club on a small inland lake in Texas. 
This boat has a lot of freeboard which means that the outboard motor has to have a long shaft. 
A British Seagull Super 40 Plus came with the boat when I bought it. 
I keep the outboard in a locker under the seat and mount it only when I need it - it weighs about 30 lbs (Note that the Honda BF2.3 and the Suzuki DF2.5 also weigh 30 lbs). Unfortunately, the Super 40 Plus outboard has no reverse gear and can only swivel about +/- 60 degrees. 
The consequence is that I can neither back out of the slip nor brake when coming into the slip. 
However, the Super 40 Plus does have enough thrust to turn the boat into a 15 mph wind. 

Several years ago, in an attempt to come up with a reverse capability, I bought an air cooled outboard that claimed to be 2.5 hp, but it did not have enough thrust to turn the boat into the wind. 
Since then I have learned that what matters is the thrust delivered not the horsepower.
However, figures on thrust are hard to find whereas horespower is usually how the motors are rated.

From an article titled "Choosing an Outboard Motor For Your Dinghy" at ezinearticles.com, I did find the following information: 
"A Bollard pull test showed that the Mercury 3.5hp and 
Tohatsu 3.5hp were the most powerful at 90lbs of thrust 
(These two engines along with the Mariner are virtually identical). 
The least effective was the Honda 2.3hp at 66lbs of thrust. 
In between were the Suzuki 2.5hp at 83lbs of thrust, the 
Yamaha 2.5hp at 78lbs of thrust and the Parsun 2.6hp at 70 lbs of thrust."

The Super 40 Plus is rated between 2.5 and 3.5 hp, and it has been said that its thrust is 55 lbs, but the thrust figure seems low to me, based on personal experience.

So...now...trying to tap into the knowledge in the sailing community, do any of you know what the smallest outboard motor is that can turn a Buccaneer 210 into, say, a 15 mph wind?


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## SHNOOL (Jun 7, 2007)

I ran a 2.2HP on an inland lake on my Capri 25 (larger, but lower freeboard, probably 500lbs heavier though).

in 20 knots true headwind the boat pretty much couldn't move, in 15 knots, I could do 4 knots.

The 2.2 was an old merc 2 stroke (early 90s version).. same as an old Nissan 2.2. 

Later on I replaced the Merc with a 3.5HP Johnson 2 stroke, and 20 knots of wind was no problem, would get me 5 knots into a headwind.

I presently use a 3.5hp Merc 4 stroke long shaft (vintage 2016) on my Wavelength 24, probably lighter than your boat (but not by a lot, 500lbs or so). 20 knots of wind, I can get hull speed.

The 3.5hp Merc weighs in at 40lbs for the long shaft. No reverse. integral tank... For the record the Tohatsu and Merc are the same motors at this size.
To get a reverse you must go to the Merc 4hp, but the weight is 60lbs. They also have external tank connectors at that size though. I believe you can move up to an alternator too when you go 4hp or more.


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## Bluejacket7377 (Mar 23, 2018)

Thanks, SailingUphill, for your reply - it is useful information.

Your experience tends to make me believe that my Super 40 Plus Seagull is probably more toward the 3.5 hp end of the stated range rather than the 2.5 hp end of the state range.

The significance of this is that I probably need the thrust that can be produced produced by a 3.5 hp motor.

From the previous quote "A Bollard pull test showed that the Mercury 3.5hp and 
Tohatsu 3.5hp were the most powerful at 90lbs of thrust...", I'd conclude that I need about 90 lbs of thrust.

Also, from the same quote I note "...the Suzuki 2.5hp at 83lbs of thrust...", which is almost equal to the two 3.5 hp motors, but is the same weight (30 lbs) as the Seagull.

So I am tentatively concluding that the Suzuki DF2.5 is what I need to get.

Thanks again for your help.


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## TakeFive (Oct 22, 2009)

Bluejacket7377 said:


> Thanks, SailingUphill, for your reply - it is useful information.
> 
> Your experience tends to make me believe that my Super 40 Plus Seagull is probably more toward the 3.5 hp end of the stated range rather than the 2.5 hp end of the state range.
> 
> ...


Power is power, and thrust is thrust. You're not going to get 3.5 hp performance out of a 2.5 hp motor. The laws of physics prevent that. There's no true substitute for higher power.

At a given power, you can tweak the thrust of a motor by selecting a different prop pitch, but it will always come at the expense of other performance factors. You can pick a prop that will deliver more thrust when the boat is moving slowly (typically a lower pitch prop), but suffer poor fuel economy and/or poor top speed in extended cruising use (due to over-revving). Sounds like that may be the tradeoff you're looking for. Just be aware that it's always a tradeoff, and that you'll sacrifice one factor to improve another one.

Typical motor size for a boat your size would be 3.5-6 hp.

I have the Suzuki DF2.5 on my dinghy. Overall I am happy. I like that it has a true neutral gear instead of the Honda's centrifugal clutch that can grab suddenly when you're starting the motor. I like that it's water-cooled and thus quieter than the Honda. I like that it weighs only 29 lb. I think that for some applications, 360 degree steering is better than a reverse gear because the prop is always turning in the direction it's designed to have the most thrust, so you may stop better than with a reverse gear would at the same hp.

For the Suzuki, I'd recommend always burning the gas out of the carb if you're going to leave it more than a couple days. I often go further and siphon the gas out of the tank first, then burn off the carb. The main customer complaint for this motor is from poor fuel delivery due to debris/varnish clogging the tiny fuel passages. I'm not sure it's any worse than any other small hp motor. The little motors always are finicky with debris. I have not had that problem, but I'm just barely getting started with my motor.

I'd recommend buying your motor from a brick & mortar dealer, not online. You may need the support, and if you shop around you can get just as good a price. My Suzuki was about $50 less from the dealer than the big Suzuki online outlet.


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## fallard (Nov 30, 2009)

The Bucaneer 210 displaces 3000#. I found a 6 hp outboard appropriate for use in our tidal currents on my 2500#, 18' catboat for 15 yrs. Sure, I could move this boat in calm conditions with a 2 hp motor, but it wasn't a serious option and I only did that once. Suggest the OP go with 6 hp.


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## RegisteredUser (Aug 16, 2010)

Suzuki 6hp, iirc, is 52# dry.


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