Honda 2hp for Core Sound 20?

[Terry Dunn]

I am considering an outboard motor for my CS 20. I have nice 9' oars and my wife rows pretty good. However, I will probably drag the boat to some larger bodies of water and would like an outboard.

Is a Honda 2hp adequate? How fast would it push a 20? Would it push a 20 against a 20 knot breeze?

How much better would a 4hp be?

I will not use the motor often (I hope) but do plan on a 4 stroke.

[Greg Luckett]

From the Nissan Marine website FAQs:

"What horsepower motor should I put on my boat?

There is no one simple answer to this question. There are many factors which must be taken into account, most importantly is to never exceed the horsepower rating of the boat. Other factors to be taken into account are the weight of the boat, weight of passengers/gear, and your expected use of the boat (do you want to water ski? troll around your local lake? etc). To find the best "bang for your buck" please consult your local dealer and discuss your needs with him/her. They will be more than happy to help you find the best outboard for your particular needs."

Greg's perspective: dealers will always try to sell you more than you need because bigger is more dollars and less risk for them. I have been using 5HP 4stroke outboards with standard props to push a 2700LB Catalina 22 upriver against a 5 knot current. Hull speed is only a little better than that anyway. If you just want an auxilary motor, a 2 hp may be good enough. You won't ski behind it, but if you can move about like rowing or sailing, why bigger? A guy I just talked to is selling a 15 foot Aluminum fishing boat that he used an 18HP on. HP = speed in that case.

[Garry]

I would think a 2 hp would be barely adequate. I used to have one on my 8 ft. dinghy which was about right.

I had a 4 or 5 hp (senior moment) on my 19' Starwind which seemed about right. I didn't have to push it to achieve hull speed. It had some reserve for times like trying to get back to the dock during a squall pushing against 30-40 knot gusts and a current at the same time.

You would probably be pushing the 2 hp at max most all of the time. While a 4-5 hp would be operating at 3/4 throttle most of the time with reserve for when you need it.

Just my opinion, though.

[Greg Luckett]

The real trick to this is the pitch of the prop. Most outboards come with props made for speed rather than power. I am going to pick up a different prop for my 5HP Nissan this Saturday. Incidently, even with the speed prop on it, it would only need to operate at about 50-75% to maintain hull speed on my Catalina 22 (with its wing keel). That was definitely a displacement hull.

Gary, what sort of dinghy were you pushing? Those things people call dinghies and I call rubber rafts (Zodiacs) require a lot of power to move. Try rowing one. A light boat not trying to reach planing speeds does not need to be very big on HP. All boats are displacement hulls at low speeds, I think.

[Garry]

It was an 8' nesting pram very similar to Graham's Catspaw.

[Greg Luckett]

Sounds like a 4 or 5 hp should do it then?

[Rob Blackburn]

Well, I am a self professed authority on this one. A bloody expert as we say in Australia.

There is only one motor to get. 5hp. Max power to weight. Only one cylinder so not as smooth as you would like at some rpm settings. But lighter than a 6hp by far.

If you are just fooling around near home, I would get an electric trolling motor for dead calms. Rowing is fine. We have done it a few times and it is fun and you cover the ground. You need to move the mizzen out of the thwart though if you have followed the plans otherwise you can't get a good go at it.

If you plan to go places and expose yourself to wind and waves, you need a motor that gets you there. My Tohatsu 5hp cruises with 4 guys, camping gear and food and alcohol for a week at 4.5knots (GPS) at about 60% power. 6.5knots is about hull speed and it will do that at full throttle. Not pleasant on the ear but that is life.

Also it uses stuff all fuel.

http://homepage.mac.com/blackburns/PhotoAlbum48.html

Shows us cruising...

Rob

[Garry]

Rob,

Seems like sound advice. I enjoyed your slides. Looks like a fun cruise.

Question: Does "Also it uses stuff all fuel" mean it uses a LOT of fuel or VERY LITTLE fuel? Please translate for us poor non-Oz people

Thanks, Garry

[Rob Blackburn]

Oops my colloquialisms obviously don't travel that well.

I filled the standard 12.5 litre tank and took two more 10 litre tanks with me. I used about 14 litres in the week and that included two big motor legs. I would plan on under 2 litres per hour off the top of my head. And we weren't sparing it either as my mate has a 15hp on his dory and we had to keep up. It was interesting to see how much he used for the same trip as he took 70 litres and used about 50. For the same distance travelled. His boat had a lot more weight and is not as easily driven as the cs 20. (It was dry with his crew reading on the way home with us in our wetsuits/oilskins soaking wet.)

Cheers.

Rob

[Terry Dunn]

Thanks to all of you for the great advice.

I planing to get a 4 or 5 hp Mercury 4 stroke. I am choosing Mercury because I like the color and the sound of the name. Very scientific.

[Rob Blackburn]

If you are going to buy a Mercury as I was fine but the Tohatsu is the same motor made in good old Japan and here in Oz was about 400 bucks cheaper ie 1300 vs 1700 for the identical motor.

I got the one with the external tank as I don't know if the merc comes std with that. You may have to check that. I can't quite remember the details but there was something to do with this. It could have been something to do with there not being a hose fitting or some such rubbish.

Have a look first.

Rob

[Rob Blackburn]

I personally feel that my boat is wet. Fullstop.

If you arrange it so that your wife is sitting about halfway down it is not too bad but you will hear about it.

I think when you look at the CS 20 from the front it has a quite vertical side angle (can't think of the right term). This tends to slop spray aboard in my experience.

But it is the way the bottom of the hull carries out to the sides a long way

instead of how a dory is built that gives it it's stability.

This is purely my theories on it. My mate has a dory and it has exagerated flare in the bow section, is incredibly dry at all points of sailing but is very tippy and slow. So, I prefer a bit of spray and the dory behind me about 2 miles...

I don't know about a dodger as you would have difficulty seeing over it. Face facts, it is a low boat that goes quickly, you must get some spray.

Rob

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