Jack plate for a CD 22’

[petemos]

Hi I have figured out that when the dealer mounted my 115 Suzuki, it was too low in the transom and has to be raised 2-4 inches. That being the case and the need to maybe play around with the actual settings, has anyone installed a jack plate on a CD 22’? If so any pro’s or con’s to doing this. It would seem except for the costs to be a great tool for fine tuning the engine height and also allow some on the water adjustments for boat load and or water conditions.

Thanks Jim

[redbaronace]

Never installed a Jackplate on a c-dory, but did install one on my previous boat which was an Arima 19' boat. The engine was a 115 Yamaha from 2005.

The benefit of the jackplate was that it allowed me to use an XL shaft engine on a boat which would normally be set up with a Long shaft engine. With the jackplate, I was able to adjust the cavitation plate even with the bottom of the hull and the performance was outstanding. The type of system I used allowed one to make the initial adjustment to the motor height and leave it there from then on out.

The downside of using a jackplate is it adds weight to the rear of the transom. Also, it places the engine further back thereby changing the weight distribution.

My 2cents are that they are good, but be careful with your mounting as you will be making holes through the transom.

PM me with any questions you might have.

[thataway]

Normally you will be able to move the engine up or down by a couple of bolt holes--and see how the boat performs. There are some boats and some issues where a Jack plate will be very beneficial. The C Dory is a boat which is well established--it is not a high speed boat, where you might try and get an extra 2 knots at 55 knots.

In setting the engine further aft, there is also the issue that the engine has te set slightly higher.

I would want to know if you can move the outboard up without having to redrill the transom. What is the WOT speed of the boat? and What are the WOT RPM. How is the boat currently handling?

I have to assume that the engine was mounted so that the ventillation plate is at least 2 to 4" below the bottom of the boat.

[petemos]

Hi yes the engine was mounted 3-4” below the ventilation plate and its bracket is sitting on the transom. I have been playing with different props and installed a permtrim years ago. It was better docking with the permtrim and was able to get the bow down somewhat. I really can’t get the bow down to any great extent, without full tabs. I also have a very bad splash with my wake, so I know raising the engine is the way to go now. I talked to my Suzuki and he tells me he has never mounted a Suzuki directly on the transom, as they just seem to sit lower in the water for some reason. As I only have the boat in the water 4 weeks a year, the tuning process takes me a long time, unless I spend all my time playing around. I was thinking if I had to move the engine, maybe I should just install a jack plate so I could keep making adjustments over the short summer and then not have to deal with pulling the engine up and down, by lifting it. I could then go back to the prop changes and fine tune everything. I get about 30 mph with the boat floored and 5200 RPM. That with a 4x18 prop. I’ve gone up and down with the props 3X17, 4/16, and 4/20. With the current setup the 4X18 seems to give the best handling and performance. I’m usually running a light load. 15-20 gals of gas, no water, 2-3 people and beer.

Thanks Jim

[thataway]

I suspect that you mean that the engine was mounted so low that the anti ventiallation plate was 3 or 4 inches below the bottom of the boat. There is no magic about Suzuki engines that would require them to be mounted lower. I suspect you have a dealer problem, if he mounted it that low!

It would be very simple to raise the engine 2 holes and have the problem solved.

I am confused by the prop "specs" you give. Usually there is diameter and then pitch. You can also mention the number of blades--which I believe that you are doing, instead of diameter.

For example you might have a 13 7/8" or 14" diameter and 18" pitch 4 blade prop. Also the material which the prop is made of is important: SS or Aluminum.

Only a month of boat use a year? There are folks with much higher latitude who use their boats 4 to 5 months a year. I am currently at the same latitude as you are in Prospect Bay, and folks here get at least 4 months use a year. That is the beauty of the C Dory!

Yes, you can certainly put on a Jack plate--which one are you considering? It is just that there are hundreds of C Dorys who are getting excellent performance and don't need a jack plate. You can probably get more MPH with proper mounting of the engine. However above 30 mph the C Dory gets a bit more difficult to handle. I would bring the engine up one hole to start with, put a flat surface on the transom, trim the motor so it is straight down (not over trim, to be more than vertical) and if it is still over 2 inches below the transom, bring the engine up another hole. Problem solved.

[petemos]

Hi, I have a Piranha Propeller which I think is 13” in diameter. The 4X18 I was referring to was the number of blades and the pitch. Yes I have a dealer problem, as he mounted the engine that low, and since he is no longer a CD dealer and is 500 miles from my home, I just have a problem now. I know there are ways to jack and or move the engine up myself using the trailer and or a floor jack, but after dropping my 125lb kicker last year, I’m just not comfortable doing this 475lb job right now. I am going to get the marina to do it, until I get an engine hoist or block and tackle setup somewhere. That is why I thought for a few extra bucks going with the Jack Plate would give me future flexibility, as the up down would just be a ratchet turn away. I was thinking of going with something like this Manual PL65 from Cabelas. I may have missed the boat this month as I’m not sure my marina will anything it in stock now, and I want to get this thing raised for next week. If the problem is fixed on the first try, then I will forget about the Jack Plate. I will definitely check the transom alignment with the ventilation plate and insure it is close to alignment or within a hole of it.

The reason that I don’t use the boat more, is that this is a vacation home and I only get up to it once a month or so. In May the lobster traps are still in, so you can’t cruise around without getting tangled up, that blows Memorial Day week. For Canada day and the 4th of July, I will launch it this Friday keep it in for a week and then pull it out. I don’t want to leave it unattended at the dock for a month. In Aug, if I am lucky, I will be up for 3 weeks and will have the boat in for most of that time. Comes Sept, if I can’t stay a week, I don’t normally launch the boat for a day or so, I just use my zodiac and scoot around. As I have to keep the boat outside in the winter, I like to get it winterized in late Sept or mid Oct before it gets real cold, when I hate doing these things. I also have to pull my Dock and Ramp, out as this is also something I don’t like to do when it is real cold. Once I retire, I will use the boat more and you are correct, that is why I bought this type of boat to have a more extended season.

Thanks again for all your help. Have a great summer.

Jim

[thataway]

This is why one needs to give all of the information when posting. A Piranha prop is composite, and you can adjust the pitch to a certain degree.
There is a lot of flex in a composite prop. The "usual calculations" don't work.

For the max effeciency of the boat you want to go with a SS 14" prop. You want the WOT RPM to be in the 5500 to 6000 range. Generally, (unless heavily loaded a 3 blade prop is best on the C Dory 22).

A "come along" and a stout tree work great for pulling the engine up to re-align the bolt holes.

Sorry that you don't get to use the boat more!