​DIY side-mount for motor on double-ender canoe?

[Guest]

Here’s the deal. I have a 20 foot long x 40 inch wide, 105lb freighter canoe. I don’t paddle tandem anymore, even in lightweight, nimble canoes, so that beastly burden has not been on the water in years. And that just isn’t right.

A friend has a use for it in hauling out the tools and materials needed to do site maintenance, and a motor would be beyond helpful, all the more so because he has 1.5 million acres of sites to choose from (Everglades).

A square stern Grumman 19 footer would be ideal, especially for oyster bar scrapage, but those are unicorns on Craigslist.

That heavy and big arsed double ender tripper should easily accommodate a small gas engine, probably something like a 3 to 5 HP range and carry a half ton of tools, gas and gear, especially with a solo motorman.

Does anyone remember what HP the Tripper XL was rated for enginewise?

FWIW, here’s a freaking 16’ Camper with a 2.5 HP motor.

https://www.youtube.com/watch?v=PWC_pNODzY4

Oh heck yeah. I might even reconsider my distaste for motors. That dislike is based largely on a failed history of maintaining small engines, but if it was someone else’s motorman problem I believe I could easily acclimate to sitting in the bow and watching the world go by.

Most of the DIY motor mounts I have seen are for electric motors. Does anyone use a small gas-motor mount in a freighter canoe? Got a DIY design, or other recommendations?

 

[Cookannapurna]

The book by Gil Gilpatrick "Building Oudoor Gear" has a chapter on building a removable motor mount and fiberglass splash guard. I built both for my XL Tripper to use for fishing on the lake we live on. Both have handled a 3.5 horse gas engine for 3 years now.

 

[Muskrat]

You probably can't go wrong with Gilpatrick motor mount. I watched a documentary on pbs the other day with Gil leading a river trip. He was motoring along with what looked like a 4 hp towing two other canoes behind.

Link to the video:
http://video.pbs.org/video/2365361940/

Just build one like the electric motor mounts with maybe a little sturdier gunwale clamp system.

 

[Guest]

The book by Gil Gilpatrick "Building Oudoor Gear" has a chapter on building a removable motor mount and fiberglass splash guard. I built both for my XL Tripper to use for fishing on the lake we live on. Both have handled a 3.5 horse gas engine for 3 years now.

Many thanks, that is just what I was looking for and I ordered a used copy of the book. Might be some other fun stuff in there to build as well.

I’m sure I could cob something together that would work, but most of the DIY designs I have seen are for electric motors and for a 20 footer with a gas engine I’d rather go with a proven design.

I actually had a side motor mount years ago. I bought a used MRC Explorer for a couple hundred bucks and the seller proceeded to throw in various accessories; four nice paddles, a T-bar for a hitch receiver and a side motor mount.

I had no forseeable use for the T-bar or motor mount and paid it forward by giving them away when I sold a different canoe. Ooops.

 

[Guest]

A follow-up question for anyone who uses a motor on a double ender. How far from the stem (and on what length canoe) is your side motor mount positioned?

I know bupkis about motors on double enders. On a square stern the motor is (obviously) on the back. The motorized freighter will largely be used by a single boatman carrying a heavy load of tools and gear (and water), so trim weight will not be an issue.

But the freighter is a 3 seater, with seats positioned:

Center of stern seat 3.5 feet from stern
Center of bow seat 5 feet back of bow (symmetrical hull)
Center of “center” seat 8 feet from stern

One issue that may come into play is the depth of the hull at the motor mount vs the length of the length of the shaft. The freighter is 20+ inches deep behind the stern seat and 16 inches deep behind the center seat, and that 4” difference might be needed to properly submerge the propeller.

I’m assuming that the motor would best be mounted as far back as possible, behind the stern seat, but that is based on zero practical experience, and for a variety of practical and purposeful reasons the side-mount might be better at bow-backwards or even the “center” seat position.

This may take some experimentation.

First order of business will be a straight-up trim check. Replicate a heavy gear load in the freighter and hang a 30 lb cinder block off the side to approximate the displacement of side-mount motor weight. Check that for trim and pitch feel from stern, center and bow backwards seating.

Maybe check it as well with a lighter gear load, and as a tandem. I can envision the freighter being used as a motorized tandem, or carrying a lesser gear load out from a base camp, and somewhere in the 3, 5 and 8 foot distance from the end is the best position for a side motor mount.

Or, more handily, the best two positions, with gunwale clamp holes* drilled to accommodate two different seating positions. A side motor mount HAS to stick out past the outwale on the business end, so it doesn’t much matter if it sticks out a couple more inches on the off-side in a narrower gunwale position.

*Holes, not slots. If the mount needs only fit it two possible locations it not be a “universal” fit with slotted clamp adjustability. That is always the sloppy part of using a “universal” clamp system, and a couple of sized to fit clamp holes would afford the opportunity for a much more solid fit, maybe clamped between brace blocks installed on the bottom of the inwale

And, after some rudimentary trim check, install the side-mount and motor and take it out under power for some test runs in various guises. Oh heck yeah, this sounds like a helluva good time!

I was looking for another canoe project and I think I’ve found one that will teach me lots of new stuff. Best of all the closest the freighter has come to water in the past 5 years has been taking it off the racks to wash off the pollen.

And that is just wrong.

 

[Odyssey]

heck yeah! I'm ready for a whole round of photo laden reports. I love boats and motors, despite never having owned any.
I can smell that exhaust, gas and water, hear that gargling idle and splish splashing wake.

 

[Guest]

heck yeah! I'm ready for a whole round of photo laden reports. I love boats and motors, despite never having owned any.
I can smell that exhaust, gas and water, hear that gargling idle and splish splashing wake.

Ody, I grew up with canoes, but also with outboards, from 1960’s 3.5 HP Johnsons and Evinrudes on little jonboats to twin 150PH Merc’s on the back of a used DNR chase boat. We lost that boat, and others, in Hurricane Agnes in 1972.

I loved the sensation of effortless speed and power, but the maintenance, sheered pins, busted props and other difficulties helped steer me away from motors toot sweet when the upkeep was mine.

I do re-live childhood memories with that 2-stroke exhaust smell, and if paddling in the presence of small motor boats I admittedly breathe deep for an olfactory trip to my youth. But, stinky reminiscences aside, two strokes are horribly inefficient engines (something like 70 percent combustion in top operating order), hence the gassy glassy sheen they leave behind on the water.

A small, modern 4-stroke is quieter, more efficient, less polluting and less finicky. I could live with that. Especially if the motor was someone else’s problem.

I am psyched to bring the freighter into the shop and start tinkering with a side motor mount.

 

[Cookannapurna]

I agree with the thought of behind the stern seat, that is where I mount mine on my OT XL Tripper. I followed the directions in Gil's book as far as prop height in relation to the bottom of the canoe and have had no issues. His design has few measurements as it is ment for you to adjust the measurements to fit your canoe and motor. I was able to build it from scrap hardwood and les than $10 in hardware. It really is a slick and easy to build design, that is both heavy duty, and fit to your canoe.

 

[Odyssey]

It's a funny world. Last weekend, and before this thread was born, I was sitting on a rail-trail trestle over looking a quiet waterway that links a small town with nearby ponds and marshes. While my wife and I were munching grapes and sipping water I watched as a fishing dude pulled in his line and started up his electric motor. He had a DIY side motor mount on his old canoe (mock birchbark aluminum) and was relocating, looking for another luckier fishing spot. He putt putted through the channel right below us. I'd never seen this kinda thing before. It looked like he'd permanently fixed 2x4s and plywood across the stern for his small and quiet motor ( e-motors likely required for Conservation Area waters). His motor was suited to trolling, but I bet with something just a little stronger it could be a workhorse. It looked pretty cool. I stole a moment and daydreamed of lazy afternoons amongst lily pads and fishing lures.
It sure looked peaceful.

 

[Guest]

(Last week in the Adirondacks, homemade motor mount)


I have some experience with a lightweight, and quite expensive, electric brushless motor on both tandem and solo canoes. I have learned a few things that might be transferrable to your circumstances.

The motor should be located as far to the stern as practical. If mounted closer to amidships, there is a greater risk of risk of not being able to turn enough on demand and even upsetting the canoe if you happen to be using too much power and turn the motor too far facing the canoe (to go right when the motor is mounted on the starboard side, for example).

The ability to yank on the tiller to raise the prop, partly or all the way out of the water, to get vegetation off the prop, or to clear shallow, underwater obstacles, is important. This puts a big strain on the motor mount. So, a fixed mount is much preferable to a clamp-on mount as the clamp-on tends to work its way loose.

It seems like the paddling-focused boards are generally hostile to discussions of motors. I understand the instinct, but there are lots of perfectly valid reasons for putting a motor on a canoe. The fishing boards talk about motors but mostly in the context of trolling motors, and very heavy batteries, and bigger, heavier canoes/boats, and a general lack of concern for weight, which is not applicable to what I want to do.

I too grew up with big outboards on boats designed to plane up and go fast. There is a place for that, but I really enjoy using a low power, low impact electric motor on the displacement hull of a canoe.

Best of luck with your project.

 

[Muskrat]

I'm interested in motor canoes too, not necessarily electric. I have been thinking about another boat build along the lines of a rapid robert drift boat for running the Missouri River and other spots around me, but a small gas motor attached to my canoe might just do the trick of floating down a big river to a secluded campsite and then motoring back up to my truck the next day.

At first glance I don't really want to see a bunch of motorized canoes on the water, but if it saves me a gasoline powered two car shuttle, what the heck.

 

[Guest]

I'm interested in motor canoes too, not necessarily electric. I have been thinking about another boat build along the lines of a rapid robert drift boat for running the Missouri River and other spots around me, but a small gas motor attached to my canoe might just do the trick of floating down a big river to a secluded campsite and then motoring back up to my truck the next day.

At first glance I don't really want to see a bunch of motorized canoes on the water, but if it saves me a gasoline powered two car shuttle, what the heck.

Good point, I hadn’t thought about the fuel savings of shuttle elimination. But having run out of fuel with outboards a couple of times (including once at the far end of Elephant Butte Lake) I might be more tempted to motor upstream first and come back with the current.

The out of fuel scenario would also give an advantage to gas power. I have generally found motor boaters to be helpful when in need and cadging enough gas to get back would be a likely possibility if around other motorists.

The freighter will largely be used as a workboat, and as such a small motor makes sense. While an electric motor would offer some advantages, quieter and less polluting, I’m not sure of the power to drive a heavily laden 20 foot canoe, or of the travel distance provided by a deep cycle marine battery under such demands.

Part of that is also my desire to have only one or two power sources. I have slowly transitioned most of my battery op gear to AAA’s and prefer to have one type of stove fuel. A gas motor might see me going back to a multi-fuel (gas) Coleman type stove.

Of course there is always this:

http://www.westmarine.com/buy/lehr--...haft--13498993

$1000. But if ran everything off propane……

That is 1/3 pricier than a 4-stroke Suzuki 2.5hp, and I have no idea how the run times compare. That little 4 stroke Suzuki gets high marks in reviews and outboard threads, although 2.5hp might be underpowered on a 20 foot canoe. $700

http://onlineoutboards.com/suzuki-2-...FckYHwodzdQFiA

A similar HP electric is closer to $2000, plus another $100 for a deep cycle marine battery.

The most cost effective solution may be something like a used and well maintained late model 3.5 to 5 hp 2-cycle.

BTW – Lots of interesting info and opinion here and in other threads on Alaska outdoor/boating forums.

http://forums.outdoorsdirectory.com/showthread.php/98761-Motor-set-up-for-20-double-ender

 

[ezDuzit]

My limited canoeing experience is many decades old. But my engineering and boat building experience tell me that the outboard wants to be as close to the centerline as possible, minimizing the offset motor's tendency to constantly turn the canoe in one direction, thus reducing the counter-steer required for straight-line travel. Other side benefits are that there is less tipping moment from the weight of the OB, and less rolling moment due to offset thrust.

The OB mount should distribute its load over a large area, as opposed to high pressure points, especially on wooden gunwales. And it should place the OB's height so that the lower unit always remains submerged, even through rolling and wave action.

2-strokes have the weight advantage. But more and more waters are being closed to them.

 

[forest runes]

I have been in & operated both double enders & square sterns with gasoline motors and prefer the double enders as it is much more comfortable as there is less craning around ( You can face forward & steer rather than straddel the seat.). Both aluminum & diy wood mounts work well as long as HP is reasonable. Yes you have to counter steer but that will come natural & is no big deal. A small dingey moter will propel a canoe nicely

 

[Guest]

my engineering and boat building experience tell me that the outboard wants to be as close to the centerline as possible, minimizing the offset motor's tendency to constantly turn the canoe in one direction, thus reducing the counter-steer required for straight-line travel. Other side benefits are that there is less tipping moment from the weight of the OB, and less rolling moment due to offset thrust.

Behind the stern seat makes a great deal of sense for a basic physics standpoint. Behind the stern seat should work well with the freighter, especially since the stern seat is pinched far back for a 20 foot long hull.

The OB mount should distribute its load over a large area, as opposed to high pressure points, especially on wooden gunwales. And it should place the OB's height so that the lower unit always remains submerged, even through rolling and wave action.

The freighter has vinyl gunwales with aluminum inserts. I’m psyched to get the Gilpatrick book Cookannapurna mentioned above, especially since it contains design coniderations for gunwale height and motor shaft. From what I have read about side-mount motors on double enders the addition of splash guards sounds like a wise and easy idea.

2-strokes have the weight advantage. But more and more waters are being closed to them.

2-strokes do have that advantage, although the weight difference is getting to be less and less. I had not considered that waters might be closed to 2-strokes, but leaving behind that glassy sheen of 30% uncombusted fuel would not make me a happy motorist.

I have been in & operated both double enders & square sterns with gasoline motors and prefer the double enders as it is much more comfortable as there is less craning around ( You can face forward & steer rather than straddel the seat.). Both aluminum & diy wood mounts work well as long as HP is reasonable. Yes you have to counter steer but that will come natural & is no big deal. A small dingey moter will propel a canoe nicely

Thanks for those words of experience. I am psyched to get into this project. Too psyched; the boat, motor and driver probably will not come together until October. Even so I am already looking forward to a few test trips under power with me as lazy bow weight.

 

[JoelBeckwith]

Can't wait!!!

 

[dave0]

I think Micheal up front will suffice for a test run. Now we have to figure out an outrigger for this rig Joel.

 

[JoelBeckwith]

The Outrigger will be my kayak. Perhaps 1 on each side with a folding tent platform.

 

[Guest]

The book by Gil Gilpatrick "Building Oudoor Gear" has a chapter on building a removable motor mount and fiberglass splash guard. I built both for my XL Tripper to use for fishing on the lake we live on. Both have handled a 3.5 horse gas engine for 3 years now.

Cookannapurna, what is the shaft length on your 3.5 hp canoe outboard?

 

[ezDuzit]

...I had not considered that waters might be closed to 2-strokes, but leaving behind that glassy sheen of 30% uncombusted fuel would not make me a happy motorist...

I think the 30% estimate is way high. But perhaps there is a more biodegradable oil suitable for 2-stroke pre-mix.

Standard OB shaft length is 15". Normally the next longer available is 20", which is available in the 3.5 hp Tohatsu 2-stroke. I've owned both 15" and 20" versions of this motor.