Outboard Jet for motor?

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palasz

New member
Hi-

Im beginning to look at a 22' Cruiser for a winter boat for our river in the NE. We typically run outboard jets since the water can get shallow. Is this an option for a C-Dory? I see everyone running the 90HP HONDA outboard prop.. The water in our river is pretty calm...no waves to worry about.

Thanks,

Mike
 
palasz":uwc88fpc said:
Hi-

Im beginning to look at a 22' Cruiser for a winter boat for our river in the NE. We typically run outboard jets since the water can get shallow. Is this an option for a C-Dory? I see everyone running the 90HP HONDA outboard prop.. The water in our river is pretty calm...no waves to worry about.

Thanks,

Mike
Click to expand...
While it certainly is possible to run an outboard jet on a C-Dory, I wouldn't advise it. First, most boats on which jets are run are constructed of aluminum for a reason. E.g. if you're running in really shallow water, aluminum is far more forgiving when you hit a rock. Second, many jet boats have a tunnel to really allow water to get to the jet when the boat is in shallow water. Third, adding a jet to an outboard reduced the usable horse power by about 30%. Fourth, if you ever want to sell your C-Dory, an outboard jet will be seen as undesirable by the vast majority of potential buyers.

You can run a C-Dory (slowly) in as little as about 18" of water with a propped engine. If my application was to do that, I'd run a 6-9hp kicker + 90hp main on a 22 and only use the kicker in really shallow water.
 
Ok.. I understand those limitations.

So, with a 22' cruiser on plane it will need 18" for the prop to clear? I was under the impression that draft was 7" (not moving) and was thinking maybe 12" with an outboard prop..

We have outboard props that run our river they are just a little limited as to where they travel.

Thanks,

M.
 
I think a jet would work great on the C-Dory 22 nearly flat bottom. You should have no trouble getting nice clean water on the back of a 22. I do think though, you will need a 115 hp (or larger) to really be happy with the performance. As far as resale, you can always slap another lower unit on it when you resell it.
 
palasz":13pfwkud said:
Ok.. I understand those limitations.

So, with a 22' cruiser on plane it will need 18" for the prop to clear? I was under the impression that draft was 7" (not moving) and was thinking maybe 12" with an outboard prop..

We have outboard props that run our river they are just a little limited as to where they travel.

Thanks,

M.
Click to expand...
People are usually swinging a 15-17" prop and typically the cavitation plate (which is above the prop) is even with the bottom of the hull. Add a skeg, and you probably have closer to 24" below the hull. If you want to travel in shallow water and you're willing to do it at low speed, you can trim up a little and get into shallower water but I think 18" is really pushing it. Getting on plane with a 22' in will require some period of time (a 4-10s) when the bow is up and the stern is a bit lower in the water and will require that the engine is trimmed down. So I think you'd need even more water to get on plane. Remember, most really shallow running jet boats have a tunnel that allows the jet to be higher on the boat and still get water, you don't have that on a C-Dory

That said, being on plane in a fiberglass boat in 12-18" of water in a river (where the bottom structure can change frequently) seems to me like one is asking for trouble.
 
During the Winter the tides are low, and we only have 18" of water over the sand bar coming into our home bayou. We trim the boatboards in the up, and have them potion. A jack plate would do pretty much the same thing--perhaps at a geater speed. But rocks are going to be a significant risk still..
 
I saw a photo on a friends facebook page of what looks like could be a great river running boat. Silver Streak. http://www.silverstreakboats.com/
Anyway back on the C-Dory. I just took some measurements of my boat while sitting on the trailer. I have a 22 with a Merc 115 hp outboard that swings a 13" prop. The cavitation plate is even with the bottom of my boat when in the normal running position. The bottom of the skeg is 17" below the cavitation plate. The waterline on the back of the boat is about 10" above the hull bottom. Sooooo.... sitting still in calm water, with the motor down, looks like I draw 27". With the motor up, 10". 18" seems like a good average going no wake with the motor trimmed up, or full out on plane. FWIW.... Colby
 
Having ran a lot of jets in the rivers here in the nw I can say yes you can put a jet on a cdory and it would be a good river boat.

For the use that he is taking about , which is low water WITH fast currents up to 10 knots or more, going slow and titling motors up is not a option. we run the rivers at 25mph plus with a jet sled, glass or alum both have advantages, over water as shallow as 8 inchs.
this has to be done to get from one hole to another over rocks and rapids. If you have not seen this done you should go give it a try with a guide or a friend Its a hoot.

The lighter the boat the shallower the water. My friend Alex had a 15ft open boat with a 4ohp jet that we ran in as little as 4 inchs with two on board. Great little river runner.
a lot of guys will run a prop or a jet on the same motor depending on where they are fishing that week. it does not take 30 mins to do the swap. You just need a adjustable jack plate to change the engine height for your different uses.

I can think of a lot better boats to fish out of in the river then the cdory but thats up to you.
 
I too have a small 14 foot river boat for chasing salmon. It is a 14 foot welded Hewes with a 40 hp Johnson Jet. It will run in very shallow water at 25 (or a little faster) mph with 2 guys. As far as hitting rocks, I have hit a couple in 20 years of owning it, but it is rare I hit anything with it. As I have gotten older, and the local rivers have become exponentially busier with tourists and fishing guides, I go sporatically now as I'd rather be on PWS in the CD 22.

I personally would not run a CD 22 with a jet on a shallow river as eventually, even if you know the river, you are going to hit a rock as channels do change. And rocks and boats are bad, even for aluminum ones..... It would be expensive to fix for sure on a glass boat. As far as hp goes, I think a 115 would the absolute min hp rating I'd do (if I were crazy enough to run a jet on CD 22) as you just won't get on step fast enough, or at all.....
 
And to think I'm scared of rocks (or wing dams) even at no wake speeds; little own 25mph! The thought of water coming thru the hull where it's not suppose to isn't my cup of tea! ;-)
 
We use our C-dory in rivers and estuaries to fish salmon. We do get some strange looks from all the aluminum river boats, while we're anchored in as little as 3' and fishing. My friend calls our boat "king of the Skagit". That shallow draft was one of the biggest attractions of the boat for us when we were shopping. Our previous boat had a very deep V, and I never thought of using it in rivers. What would worry me most is that initial time period while getting up on a plane. The prop is going to be significantly lower in the water for that couple seconds until up on a plane.

It works really well for us as a river boat, except most of the ramps are not made for a boat the size of a 22' dory. We have to put in and take out at high tide most cases. Not the best situation, but its comfortable enough that we can hang out and wait for the tide change and the waves of fish that come with it.

I guess my point is, if you need a jet motor because it's that shallow.... you probably have the wrong boat for the job. Jet or prop, I wouldnt be comfortable in much less then 3' of water
 
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