C-Dory 16 Cruiser Kicker Motor Placement and Performance

C

C-Nile

New member
This message is intended for those of you with C-Dory 16 Cruisers or Anglers who are interested in kicker motor size, placement and performance.

As the result of a malfunction with the safety lanyard engine kill switch, I've been stranded on the water twice: once without a kicker, and the second time with one. As to the latter -- it allowed me to gain control of my boat and make it back to the dock safely. I strongly believe in the necessity of kicker motors, even when one subscribes to a service such as SeaTow.

Garelick Motor Bracket. My dealer did an excellent job of selecting and installing a Garelick kicker bracket (for motors up to 8 HP) on the transom.

Placement. The port side is the best side for placement for my purposes. With me weighing in at 250 pounds and sitting on the starboard side, the kicker placed on the port side of the transom provides a good counterbalance to my weight. Note: I have a swim platform on the starboard side.

The Motor. My kicker motor is a short-shaft, 4 HP, 4-stroke Yamaha. It weighs in at only 48 pounds, which is very light for a 4-stroke of this size. When the motor is tilted up and the bracket is locked into its storage position, the motor is well clear of the water. However, when the bracket is lowered, the engine is properly placed into the water.

Steering. Steering is easy; I use my main motor as a rudder. The steering is surprisingly precise, and I was even able to perform 360-degree turns (albeit slowly.) There was therefore no need for me to install a linkage steering rod between the main motor and kicker. However, when pulling into a docking slip, you need to be close to the forward, reverse and neutral switch and throttle.

Performance. After extensive testing with a total boat weight of 1,900 pounds, the motor pushed my CD16 Cruiser at approximately 5 mph at 2/3 throttle. Going to WOT made no appreciable difference in speed. This was probably close to the hull speed of the CD 16. In my opinion, 4 horsepower is more than adequate. I have read that the general rule of thumb for horsepower in a displacement mode could be as little as one horsepower for every 500 pounds of weight. More horsepower means more weight on the stern, making the boat stern heavy. If additional horsepower is not sufficient to plane the boat, it will not yield appreciably greater boat speed.

Stern Heavy? With one person in the boat, it planes just fine with a top speed of approximately 19 knots (I have a Suzuki 40 HP). However, when adding a second person in the boat, the speed diminished to 15.5 knots, because the boat was not properly trimmed. Moving off-setting weight up toward the bow allowed the boat to return to a good trim attitude and speed.

Fuel Supply Options. The Yamaha has a small internal tank, and you’ll get about ½ hour of run time from it. It also has a provision for an external tank. I put a Suzuki female connector onto the terminal end of the external Yamaha gas line in order to leverage the capacity of my main gas tanks.

Securing the Kicker from Theft. I wrapped a 6' long, 3/8” diameter, steel-stranded, Schlage security cable through the stern eye loop, and attached it directly to the motor with a corrosion-resistant Master Lock. If a thief really wants to steal the motor, they can do so, but I did not make it easy for them.

4 Stroke Motors and Engine Oil Level. Don’t fill the oil to the top fill mark. If you do, when you tilt the engine, the engine oil will leak into the cylinder head and dowse the sparkplug stopping the engine cold. It will take about 50 pulls to get the engine started again. I fill the oil to the ½ fill mark.

Pictures of the kicker motor, bracket and placement are located in my Photos Folder “C-Nile”
 
Thanks for all the good information. I have a 5hp Honda kicker and last year moved it from starboard to port, as you suggested. I get 5mph max with 2 200 lb. people aboard. I would say it is adequate, but I don't know if it's "more than adequate". My kicker is directly on the transom and does drag. I'll probably add a bracket when I get up the nerve to drill the holes. Thanks again for the info and the pictures.
 
I had something similar on the "Cachita". The auxiliary kicker (Suzuki 6hp long shaft) was dragging in the water. I had a local boat shop install a fixed motor mount that raised the kicker out of the water to eliminate the drag on the port side. The fix mount was much lighter than the Garelick mount and all the bolt holes were drilled above the transom well.

We're getting over 5-6 mpg on plane with the Suzuki 50. Boat handling is great as long as weight & balance is taken into account.

Enjoy!
 
C-Nile – to me it seems like your top end is a little slow with your main. When my boat was 16 feet and with every thing trimmed just right and perfect conditions I could hit 31 knots with a total weight of 1975 pounds. Now that my boat is two feet longer, I have never been lighter than 2550 pounds and I can still get 21-22 knots. I do have a Honda 50, but I don’t think there would be that much difference.
_______
Dave dlt.gif
 
C-Nile, I agree with Oldgrowth, when I had my 16' Cruiser, I'm certain that I achieved at least 28 Kts with a 50 HP carburated Honda. (Also had an 8 HP Honda hanging off the transom which was tied in to the main for steerage). (BTW, the 8 HP wasn't in the water running when doing the 28 Kts. :lol: )
 
I'm having some second thoughts about the suggestion to only fill the oil halfway. I think I'd appreciate a second opinion about that. Also, since the manufacturer says to lay the motor on the right side when transporting, it is harmful to tilt it to the left when carried on the transom or bracket? Thanks.
 
Marty,
I should have been more specific about my oil level comment. With respect to the Yamaha 4-stroke, 4 HP kicker -- if you fill the oil level to the full mark when it is cold, and then kick the motor up two notches for shallow water drive, the oil goes into the cylinder head and smothers the spark plug, shutting down the engine. My dealer told me to fill it to the 1/2 fill mark cold level to prevent this from occuring. If the engine is always level, you don't have a problem. On my 40HP Suzuki motor, the dealer filled the oil to the full mark, which makes sense. The oil does not run into the cylinder head, albeit if I tried to start the motor in an inclined position, I'm sure the oil would pour into the cylinder head when a critical angle has been reached. By all means -- follow the manufacturer's comments.

Dave Et. Al.,
Without Permatrim, I have to set the Suzuki to its maximum trim angle in order to get the bow down. Perhaps the force applied to keep the bow down is decreasing the speed of the boat?
 
C-Nile":36j7w35a said:
Dave Et. Al.,
Without Permatrim, I have to set the Suzuki to its maximum trim angle in order to get the bow down. Perhaps the force applied to keep the bow down is decreasing the speed of the boat?
Click to expand...

C-Nile, FYI, I did not have permatrim on my 16' Cruiser either and still achieved the speed I indicated. Additionally, the vessel was always "heavily laden" with all the items that I felt I need......which is A LOT..... :mrgreen: . After my speed increased then I would trim the motor out to assist in achieving improved speeds. Understandibly, my engine was a 50 HP carburated 4 stroke, but I still am surprised that your speed is not greater than what you indicate. Just for clarification my speed was taken from my GPS in "no current, no wind conditions, flat water".
 
DaveS:
If you look at Honda 40HP test results as posted on C-Dory's web site, it shows the CD16 with a top end speed of 24.8 knots. I am getting around 19.5 knots with my Suzuki. That's a heck of a difference. I think a major factor is that because my boat is docked, the bottom of the hull is painted with special paint that makes it easy to clean the marine organisms and grime from the hull at the end of the season. The paint is dull -- almost rough. I think it is creating more drag then the smooth gelcoat finish of a trailered boat. An added factor could be that a Honda 40 may generate more horsepower than stated, if one would believe unsubstantiated, subjective comments from some of the owners of this engine.

Thanks!

Rich
 
C-Nile,

What is your speed at different RPM's? What I'm getting at is that it may be your prop. The way to test is to see if you're achieving the proper RPM range at WOT. If you're achieving 19.5 knots at WOT, how many RPM's are you running? It could be you're overpropped and need to drop down in pitch.

With our original Suzuki 70hp, we were unable to get to the correct RPM range with the prop we had, resulting in a very sloooowww ride. Once we changed the prop, it made a world of difference.

Peter
C-Dancer
 
Peter,
You may be on to something here. AT 5,000 RPM, we get about 18.5 knots. If memory serves me right, top end RPM at WOT is about 5200 - 5300 RPM. When I bought the boat, it was missing a prop, and the dealer ordered a new one. I'm not getting the top end RPM as stated in Suzuki's literature, so you could be correct that it is the wrong prop. However, my wife and I feel more comfortable at 15 - 18 knots. So we are not displeased with the arrangement. When we replace the prop in a couple of years, we will look closely at prop pitch options.

Thanks,

Rich
 
C-Nile":qnycr541 said:
Peter,
I'm not getting the top end RPM as stated in Suzuki's literature, so you could be correct that it is the wrong prop. However, my wife and I feel more comfortable at 15 - 18 knots. So we are not displeased with the arrangement.
Rich
Click to expand...

Rich, I would agree that perhaps Peter has come up with the remedy. Most likely the majority of the C-Brats would agree with you and your wife about being more comfortable at lower speeds and many of us would even say lower speeds than the 15 - 18 knot range, however if the engine/prop combination is able to achieve a wider range of speeds, there are situations where having a higher speed is beneficial. The majority of our cruising in our former 16' and now 22' is around 10 to 14 knots.....most often on our waters, the seas dictate the speed. (ie: more waves = slower speeds..... :wink ).
 
From what I've learned on this site, it might not be good for the engine if it is lugging, i.e. working harder than it should at higher speeds. I believe this is the condition if you are overpropped. Seawolf Joe or Thataway Bob or any other experts in the field, please correct me if I'm giving bad information. :lol:

Peter
 
Jazzmanic":c7bzwkd2 said:
From what I've learned on this site, it might not be good for the engine if it is lugging, i.e. working harder than it should at higher speeds. I believe this is the condition if you are overpropped. Seawolf Joe or Thataway Bob or any other experts in the field, please correct me if I'm giving bad information. :lol:

Peter
Click to expand...

You're absolutely correct, Peter!

If the engine cannot achieve at lease the bottom end of the max rpm range, one is lugging the engine and overheating and/or overstressing it.

The general rule is to come down one inch in pitch to raise the max rpm each 200 rpm. (Very approximate, also depends on prop diameter and number of blades, etc.)

Joe. :teeth :thup
 
Peter, Joe Et Al:

On Suzuki Marine's web site, their literature states that the full throttle operating range of the DF40 is 5200 to 5800 rpm; I'm at the low end of the range. You've really got my attention and raised my level of concern. Next time out, I'm going to take precise measurements of speeds and rpm levels.

Looking further in their literature, I found they make 8 different prop sizes and pitch for the DF40:
11-1/2 x 9 (S900)
11-1/2 x 10 (S1000)
11-1/2 x 11 (S1100)
11-5/8 x 12 (S1200)
11-1/2 x 13 (S1301)
11-3/8 x 14 (S1400)
11-1/4 x 15 (S1500)
11-1/8 x 16 (S1600)

You people are obviously correct. I've got to also find out the model of my current prop.

Thanks for your excellent advice,

Rich
 
Peter, Joe Et. Al.:
We tested our boat last night to discover we overlooked motor trim angle. We've been using the motor in the maximum "in" trim angle to keep the bow down, and did not adjust the trim angle "out" as we reached higher speeds. When we perform the latter, the speed goes up to 26 knots, and we hit 5700 rpm. So this means that we have precisely the correct propeller for the engine. We use the boat in relatively rough water at times with a lot of boat traffic in the area. When the trim angle is out, one small wave and the boat slams unmercifully at high speeds. As a result, we have been keeping the trim angle in to keep the bow down into the waves, and this has allowed us to have a smooth ride at around 15 to 18 knots. However, which is now obvious to me, in the maximum "in position for trim, this causes a top end rpm of 5300 rpm, which probably strains the engine over a prolonged period of time- something we don't do anyway.

We thank you for you help,

Rich
 
Rich- I've learned a lot on this thread. Thanks for starting it. Hope you enjoy your 16footer with the 40 as much as we have enjoyed ours. MartyP
 
Rich,

I'm glad you got it all figured out. :thup Yes, it sounds like you are properly propped. However, I strongly suggest adding a Permatrim. With ours installed, the response to trimming the bow down is immediate and you don't have to have it trimmed all the way down to get the bow down to where you want it. As you can see, I'm a big fan of the Permatrim.

Peter
 
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