50 HP Honda on 22Ft classic

[T Lats]

Just wondering if anyone has this setup and has some specs on what type of speed they make and what r.p.m they run.
My boat only makes 14 knots at 4900 rpm. That is all the r.p.m that I can achieve.
Maybe I need to reprop? Am I wrong thinking the prop will give me the full 5700 r.p.m.?
Any info on this would help.

Thanks

[Larry H]

T Lats,

It sound like your prop has too much pitch. I would try a prop with 1 to 2 inches less pitch. The motor should achieve the 'wide open throttle' RPM specified in the owners manual.

Sometimes you can borrow a prop for testing, or buy one from a dealer with exchange privileges.

[Sea Wolf]

T Lats-

Welcome aboard!

You can definitely raise your rpm by lowering your prop pitch.

The standard rule of thumb is 1" of prop pitch change = 200 rpm, so 5700-4900 = 800 rpm, and 800/200 = 4 inches of prop pitch reduction. However, I'd start with a 2' pitch reduction and see what you get first, as 4" is a lot, probably too much.

What pitch prop are you now running?

The "Classic" CD-22 was designed for a 70 hp 2-cycle (light weight, about 250 lb) engine.

At 50 hp you have 50/70 , or 71% of the recommended h. p.

You'll probably get an increase to a top speed of 16-17 knots, as a guess. It's harder to determine without knowing your present pitch, and even knowing that still would leave some unpredictability because of other unknown factors.

With the underpowered situation you're in, some may be surprised that your boat will plane, but it gets a lot of help from the light weight of the engine.

Joe.

[T Lats]

Thank you guys for the info!! I will check on my pitch and go from there. I believe I will also be looking into one of those Hydrofoil attachments to help get my bow down in the water. I may also be considering a repower with a larger Honda possibly a 90 HP.
I have been keeping an eye on all the posts here, they are very helpful

Thanks again

[MikeMac]

Years ago when I was agonizing over power options for my Classic I ran across some test data for the Honda 50 (and the Honda 75). I think it was on the C-Dory site and I think it was also on the Honda site. I can't find it on the C-dory site. It is on the Honda site at the cut and paste link below (sorry, I'm a net moron).

http://www.honda-marine.com/performancetest.aspx#332

They tested a 99 Cruiser with an 11 1/4 X 13 X 3 on a 50. Top speed at 5400 RPM was 19 MPH. I would think a Classic should do a bit better with the flat bottom.

Hope this helps.

Mike

[MikeMac]

OK so when you go to my bad link, select Fiberglass-Monohull-50 and hit "Find Prop Tests" and you should see the link to the C-Dory 50 test. If you switch to 75 you'll see the link to the C-dory 75 test.

Sorry for the confusion.

Mike

[mikeporterinmd]

Interesting to look at the two 22' tests. In one case, the boat is
over-proped and the maxed at (I think) 4mpg. When proped correctly,
they got 5mpg.

We're topping out at 5700 rpm right now and getting 4.7mpg anywhere
in the 4000-4600 rpm range. Lots of tab - about 3/4, and the motor
has a mid-range tilt.

I'd have to check our pitch. We have an AL Honda prop.

Mike

[Jack in Alaska]

I would go for at least a 75 Honda if not a 90. My 1983 Classic runs great with my 90 even with a large load.
I think you are straining that 50 hp. JMHO

[jennykatz]

when i bought the Duck 2yrs ago it came with a honda 50 top speed was 16mph at about 5500 rpm way to stressed for my tastes . i bought the 90 hp suzuki best decision plenty of power with full fuel ,water and 4 people still can hit 30mph . the honda was always having fuel problems with those pesky carbs . love the suzuki i guess if all you do is go fishing and trolling i guess the 50 is ok

[Byrdman]

T Lat: I'd combine Larry H and Mac's numbers test as the starting point. Take about 3-4 props with you for heavy/light loads.

When folks ask how fast does it go, I start thinking they need to look at another hull design from our tuff C-Dory boats.

Do get your RPMs up to the correct limit with which ever type/size prop you need.

Now not asking what to repower with, I feel you are happy with the 50 you have now. With that, start with a light loaded boat and find the correct prop to get to the RPM range. Load the boat heavy, and get a second prop for that load, again, making sure you get the max RPM range. The speed things will be what they will be, because you do have a 50 hp. Many hours of good times for sure to be had with the current 50hp motor, and a couple of differant props to better take care of that motor. And... with the 50, you may find it a bit easier on the boat to move your 50-60 quart cooler away from the stern, and forward in the boat...even on the berth would help planing sooner...and...not as far to go for another beverage as you enjoy a nice, slower, smooth ride.

I have just returned from a 5 day river trip on my 18Angler classic. A new gizmo that really helped my fuel mileage with my 50 hp motor, was a "inclometer?".... the little gizmo more often used on sail boats as to show the side to side angle of the boat. I found that I gained about 1 mpg by simply keeping my hull running flat in the water.....simply by shifting the cooler from side to side a bit....

[MikeMac]

What struck me about the prop tests with the 50 and the 75 was that once on a plane the mileage was pretty much the same for the same speeds, so it takes a certain amount of power to go a certain speed and the bigger motor only lets one go faster. So if you don't need to go 25 MPH or whatever a well-propped 50 will do just fine. Actually I tend to think the 75 and 90 are too heavy for the old Classics, but we mostly seem to have them myself included. The 50 is closer to the weight of the old 2-stroke 70 the boat was designed around.

Good luck!

Mike

[josepepper]

I also have a 50hp honda on a 1995 cd-22 cruiser, I have the same problem with top speed (about 14) but a more serious problem, anything over 10 knots and the boat wants to fishtail and not track properly, this is much worse in a following sea. I have installed trim tabs but it doesn't help much, changed the angle of the motor/transom etc.. tried shifting weight around with no help. thanks for any suggestions you may have.

Danny

PS: How do I determine the pitch? Is it stamped somewhere on the prop??

[Captains Cat]

[SEA3PO]

I kinda doubt that much will help trying to push that boat with just a 50hp....I have tried to get my boat up on plane using a single 40hp...and it says...NO WAY !!!
What ya really need is to add another 50 and you would have a neat set..... I have thought if I were to re-engine my 22 I would go with twin 50's
With my twin 40 Yamaha's I average 4 to 4.5 mpg....

Joel
SEA3PO

[thataway]

Even with the correct prop, you will not be cruising at much more than 14 mph. (The Honda tests are in MPH). I am not sure if there will be that much difference in planing speed between the "Classic" (pre 87) and the "impoved". Both boats have very little dead rise aft and are relitatively flat on the planing surface.

What you are doing now is to be at the worse part of the power curve, as the boat struggles to get on a plane--This is lugging the engine, and is not good for it--or for economy.

The other thing to remember is that "tests" are done on a light boat--for example my CD 25 weight in the mid 4500 lb range, vs 7 to 8K for boats ready to cruise.

Irregardless you need to look at the pitch--it will be stamped on the prop either between two blades or molded on the back of the hub. A prop shop can also determine the pitch, either with a computer or "pitch guages/pitch blocks". One other factor is altitude--if you are above sea level, the engine will be less effecient and producing less HP.