Outboard size for Dinghy - Coastal Cruising

[Steve O]

I am faced with a dilemma.

We now have a choice of two outboards for our dinghy - one is a 1990 Mercury 8 HP (2 stroke & 73.0 lb) and 2011 Tahatsu 3.5 HP (4 stroke & 43.5 lbs).

Our Dinghy is a 9.5 foot inflatable weighing 105 lbs and the two of us weigh in at a total of 320 lbs

We are getting ready to go cruising in the Caribbean aboard our Tartan 37 in 2017 and want to know if the additional weight of the older Merc is worth it for the added power vs the newer Tahatsu.

We would like to get the opinion of those experienced in coastal cruising?

Thanks In advance

[Vasco]

Sell them both and get a 15. But seriously, the eight if you have to choose between the two.

[Sandero]

I did the caribe with a 6hp... it was fine. I now have an 8 and it's probably a bit better.

[Matt Johnson]

We carried both a 3.3hp and a 9.9hp, but found we only used the 3.3hp due to weight and efficiency. Sold the 9.9 in Guatemala and never regretted it.

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[Rainh2o2]

Might consider parts availability as well as weight...just a thought

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[SVTatia]

Things to consider on the pros and cons:
Tank - inbuilt or external
Transmission - neutral? Reverse?
Weight- Do you have means of lifting the heavier motor to deck?
2 stroke vs 4 stroke - additional torque, efficiency, noise level, maintenance.
All things being equal I'll keep the 3.5.

A lot of people like their dinghy to "plane", the rationale for which still boggles my mind - I mean, after making a crossing at 5-6 knots for many days perhaps, why have the need to drive the dinghy at 30 knots?

[Cheechako]

You might plane with the bigger one. Or for a quick trip to another boat or town alone you will for sure. Most would probably take the bigger one.... especially for having the gear shift etc. You need to decide what type of user you are though. If you like to explore get one that will plane. many times I've been returning from shopping, see thunder squalls headed our way and been glad I got to the boat before the deluge! But... even then sometime you don't make it!

[SailFastTri]

I have a 2001 Nissan 9.8 2-stroke, at 59 pounds the best power/weight ratio ever available. It runs smoother and quieter than any other dinghy motor I even used (including several 4-strokes). That said I'm selling it.


Why? I got tired of dealing with the weight, and we hardly ever had a desire to plane. We replaced it with a 30 pound Suzuki 2.5 4-stroke which is noisier, vibrates more and is a bit rinky-dink (forward-neutral but it turns 360 for reverse).


We kept the 9.8 for the first year using the 2.5 to see if we really wanted to make the switch. Yes. The 9.8 will go up for sale this spring on CL.

[a64pilot]

I find the ride is often smoother, and we stay a lot drier at times when on plane.
Plus if I ever had to hip tow the big boat with the dinghy, a bigger motor will do that much better, and if I'm not in a hurry, then you can't even hear my motor running its so quiet.
But I do wish it weighed half or less than it does.


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[Vasco]

It really boils down to how you're going to use the dink. If just for short hops to shore anything will do. But if you like to explore and look for good reefs to shoot fish the bigger the better.

[Reefmagnet]

I have three two stroke outboards - 3.3, 5 and 9.8 hp - and 2 dinghys in my collection (yes, I know I have a problem!). All are compromises. I've used my 9 ft inflatable Rib with all the motors and I'd prefer the 3.3 as the best all rounder on an extended cruise, followed by the 9.8. The main reason for the smaller motor is it is light and easy to handle, easier to manage on beach landings, a lot less likely to be stolen, doesn't need the external tank, is frugal and it actually is possible to plane one up. The 9.8 on the other hand is heavy, is a thief target, needs it's external tank but it sure is a lot of fun with all that power on tap.

I guess if you need to travel long distances quickly in the dinghy, the bigger motor is better and there's certainly no argument that a displacement speed inflatable will be a wetter ride than the same one at planing speed one. If you don't need to travel long distances by dinghy in a hurry, the smaller would be fine. Considering how ancient your 8 hp motor is, I'd probably stick with the 3.5 given the same options.

[Terra Nova]

On TN's tender, an Avon 2.85 roll-up, I can just barely plane, solo, with a 3.5hp Tohatsu 2-stroke, which I consider the best compromise between weight (27 lbs), especially single-handing, and performance (beats the hell out of rowing). A 4hp Suzuki 2-stroke easily planes it, solo. An 8hp Yamaha 2-stroke is too much power, solo, in all but flat calm conditions.

In harbor I have used an inflatable with 2hp 2-stroke to move a 43' sailboat between slip and haulout yard. This was accomplished with ease by using the dink as a tug, always pushing with the bow, not side-tied; a man on the wheel. This vastly facilitated close-in maneuvering, where the dink could push the bow or stern completely sideways, when needed. You don't need a big motor in protected waters. If the wind's blowing, sail.

[monte]

Id try splash out on a tohatsu 9.8 2 stroke. Light and powerful enough and yes, very quiet. A good compromise. I'd probably skip any brands other than Yamaha or tohatsu basically because of servicing and parts difficulties in the Caribbean. A smaller outboard would limit a lot of things we like to do in the Caribbean. You did t mention if you have davits or are planning on dismantling and stowing on deck, but either way I'd still go for a tohatsu 9.8 if you can manage to lift it.

[NakedCity]

If you are physically capable of handling the larger motor , use it.
having speed and range in a tender adds tremendously to our cruising enjoyment.

[J Clark H356]

I would keep the two stroke and not use the 4 stroke due to small jets in the carburetor and clogging with deteriorated fuel. I had a 4 HP 4 stroke Yamaha I took cruising and got so frustrated with the motor clogging I got rid of it and bought a 5 HP propane Lehr. I have an Avon inflatable floor dinghy that is about 9-9-1/2 feet long. We don't plane, but don't think that is important for the way we operate.


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