Dingy Outboard Motor

rclampitt · #1 (**permalink**) 01-10-2003

We are thinking about getting an outboard motor for our 8 foot inflatable dingy which we have aboard our Cal 31. What are the thoughts out there re: 2 cycle vs/ 4 cycle and HP enough to drag the boat home vs. what is right for cruising the shoreline in the dingy?

Thanks for any thoughts on this.

RC

asailor · #2 (**permalink**) 01-13-2003

I couldn''t tell u the main difference between a 4 & 2 cycle. I''ve noticed that 4 cycle are alot heavier weight than 2 cycle, therefore tougher to transfer from the sailboat to the dingy, so i''d stay with the lighter. As for how many horsepower, u said u have an 8ft dingy, i''ll assume it''s soft bottom or u would have specified. You most likely won''t be able to plane in a soft bottom, so i''d stick to something around a 5HP (or less), again because of weight, but also price. More horse power probably won''t result in a faster ride. On the transom of most dingy''s it will specify what the max HP engine the boat will hold, i''d be careful about going over that. Good luck.
--ASailor

devildad · #3 (**permalink**) 02-19-2003

Get the best deal on a two cycle as close to the max that your dingy can handle. When cruising these are our main harbor transportation. If the weather is bad you will appreciate the increased power and if the weathe is fine you will like it even more. I have an old avon rig and has to down size from a 15hp to a 9.8 Nissan because of weight, I am getting older. The 9.8 barley planes the boat with my wife and me in it, but I can put it in on the dingy in less than perfect conditions. I also have a hoist and davits for the dingy which I greatly appreciate.

ricekrgr · #4 (**permalink**) 02-21-2003

I have never used an inflatable. However, I helped move a friend''s 22,000# sailboat (failed transmision) with his two cycle 4hp powered (steel)dingy. It took some time to get the boat moving and had almost no effect, in slowing it.
Bob

ricekrgr · #5 (**permalink**) 02-21-2003

I have never used an inflatable. However, I helped move a friend''s 22,000# sailboat (failed transmision) with his two cycle 4hp powered (steel)dingy. It took some time to get the boat moving and had almost no effect, in slowing it.
Bob

ricekrgr · #6 (**permalink**) 02-21-2003

I have never used an inflatable. However, I helped move a friend''s 22,000# sailboat (failed transmision) with his two cycle 4hp powered (steel)dingy. It took some time to get the boat moving and had almost no effect, in slowing it.
Bob

ricekrgr · #7 (**permalink**) 02-21-2003

Sorry, I don''t know what happened.

pirateofcapeann · #8 (**permalink**) 02-21-2003

You obviously didn''t use enough horse-power!

Pi

Stormer · #9 (**permalink**) 02-22-2003

The 4 stroke runs on the gasoline you get from the gas station (or fuel dock)...the 2 stroke takes a 50:1 oil/gas blend. So - you need to mix at the fuel dock when you''re filling your fuel can. Not really a problem since the sell mixing cups to get the proportions right.

Regarding the HP...do the boat specs (either in an owners manual or on line) tell you what size engine the dinghy is rated for?

JeffC_ · #10 (**permalink**) 02-22-2003

Been there, done that. In summary:

Advantages of the four-stroke:
1. Better fuel economy (approx. 1/3 better).
2. No pre-mixing required (less hassle: ratios, cups, oil, spills, shaking tanks, etc).
3. No smoke/fumes in your eyes & nose.
4. Quieter.
5. #s 1-4 above result in lower environmental impact: evening marina putting is nicer.

Advantages of the two-stroke:
1. Much lighter/easier to haul around.
2. Less weight = easier planing (with hp being equal: my 8''8" dinghy is max-rated @ 5-6 hp).
3. Primitive design means if you know about "lawn-mowers," easier to tear down and work on yourself.

My friend''s 15-hp 2-stroke Tohatsu (God bless you!) weighs as much as my long-shaft 8-horse 4-stroke Honda. I love my ob, until it''s time to haul it around. It must weigh 60lbs, and all the weight is up in the powerhead. It''s run like a champ without so much as a hiccup, but if something did go wrong with it, I don''t think I could disassemble, repair and get it running again like I could a two-stroke motor (but that''s just my level of mechanical ability).

Your 8'' inflatable is likely rated @ 5hp. A 4-stroke motor will be heavier than a 2-stroke, and the overall weight difference, while still a significantly higher percentage, might still yield an overall weight that is manageable, depending on your age/health.

Regarding planing, I have no experience to offer, except that I did put that Honda on my 8''8" inflatable (this exceeded the rating by about 50%) and twisted open the throttle, but after 4 seconds of white-knuckled, fish-tailing acceleration, I realized how insane of an idea it was, and I''ve since repented. I expect a 5hp 2-stroke will plane your dinghy with 2 adults and some additional payload easily enough; whether a 5hp 4-stroke would, I don''t know.

My 2 cents are on the table.