Engine power vs boat rating

[khofmann]

I am sure these topics have been covered in the past but i would expire before going through all the archives. Anyway if you will indulge me, my questions are specific for a '85 Angler 22':

1. For max power rating do we take into account the main plus the kicker HP?
For instance with a transom rating of 100 hp can i run a 90hp main and a 20 hp kicker motor as long as they are not operating at the same time?

2. Can a pair of 40 or 50 hp motors be put on this boat? The transom appears to be narrow in comparison to later Cdorys.

[starcrafttom]

As i understand it the h.p. rating is for the amount of h.p. pushing the boat. In other words how fast can the hull handle. Its not about the weight of the motors, as the same h.p. motors of different brands can very a lot in weight. I am sure there is a upper limit of weight that can go on the stern and maybe that is factored into the rating. Having a 100h.p. rating does not limit you to 100 h.p. total for your main and kicker but that does not mean you can have a 90h.p. kicker next to your 100 h.p. main. That said i would not want to weight the back end of the boat down to much and a 25 hp kicker is a little over kill. I can't tell from our photo ablum what you have now but a 9 to 15 is enough. As for two motors i don't think they would fit on you older boat with the narrow engine well. I have only seen twins on the newer boats. Hope this helps

[Flyer]

As I understand the rating, its the hp used to power the boat at any one time. If you are using both the main engine and the kicker then add the two.

Yes you could theoretically have a 100 hp main and a 100 hp kicker and so long as you did not use both at the same time you would be "legal." Not so sure about the transom holding the weight.

One thing to be concerned about is engine weight, the 4 strokes are much heavier then the two strokes.

If you are using two strokes, then you may be able to put on twins. I would do some weight calculations.

[Sea Wolf]

khofmann-

The hp advice so far is very good. Max is for a single or twin operating engine(s) at one time.

There is NOT sufficient room for twins on the transom of the Classic CD-22's (Pre-1987).

The Pre-1987 C-Dory Classic is rated for less than the 100 hp used as an example (only),. The boat was designed for a 70 hp 2-cycle engine of about 250 lbs. or so, but a 90 hp 300 lb 2-stroke was also considered OK.

We have seen up to a 115 hp 4 stroke engines weighing close to 400 lbs mounted on these boats, but generally a 70-90 hp 4-stroke is best, which weighs about 370 lbs, typically. You'd only need more hp if you frequently carried very heavy loads and were concerned with maintaining top speeds for safely outrunning bad weather. A 115 hp engine on one of these boats would require large trim tabs and very careful and skillful managment from the helm to use without getting into trouble.

The Classic hull is absolutly flat on the bottom (looks like a clothes iron's bottom) and handles well in chop and swells at moderate speeds, at slow trolling speeds, or at rest. As the hull becomes overpowered, it becomes a bit difficult to manage and is somewhat unpredictable. This is also true of the 1987 and later hulls, which have a shallow modified V bottom, but to a slightly lesser extent.

Your best course of action would to use a single and kicker combination.

The main motor should be from 70 to 90 hp. A 4-stroke will be best, although an Evinrude etec direct injected 2-stroke would be about 75 lbs lighter, which would be marginally better in ride characteristics.

I'd stick with a four-stroke kicker motor, from 8-15 hp. Personally I'd get a High Thrust motor with 8-10 hp or so. The High Thrust motors have larger lower ends, bigger props, and lower gearing for better energy and momentum transfer. They're more rugged, overall.

I'll leave it to others with this type of set up to discuss what type of kicker motor mount is most suitable for the Classic 22's transom at the side (outside the motor well). Controls are also another issue to be decided upon.

Good Luck!

Joe.

[khofmann]

good feedback, thanks to you all. I have not narrowed down what i want to do yet but i do like the idea of a lighter weight direct injection engine for the main. The 70 seems like it is struggling a bit too mus BTW to Sea Wolf my boat is rated for a 100hp or so the manufacturer's placard states. That was one of the reasons for my original question.

[thataway]

The older 70 may not be putting out 70 hp. It might be worthwhile to do compression tests, and tune up the engine. The other question is the prop the best for the load and elevation? What RPM will the engine reach at Wide open throttle.

We found that a 90 hp engine worked well for us on the C D 22.