Jon Boat Stability Questions

Both these boats are designed as planing boats. When not driven fast enough to plane, the transom will be dragging a bunch of water. That saps up some of the driving force from the small electric motor. The boat will move but energy is being wasted by the design of the boat. A longer boat will have less drag and have much better fore and aft stability. The longer boat will also have better sideways stability than a shorter one of the same width dimensions.

 

Yes, a longer boat will have less drag. I am not aware of a (slightly) longer boat that is otherwise similar enough to the two candidates I outlined - stable, high quality, all-welded, good interior layout, lightweight and easy to handle. Are you aware of any?

 

It does, so long as the collar is securely attached to the gunwhale.
But it's effect on stability will only kick in when it starts to become immersed as the boat heels (if it is still above the waterline for a particular load condition).
If the underside of the foam collar is just kissing the water surface at zero angle of heel, then the effective beam for stability purposes is the overall beam including the collar.

One example of how something like this can have a huge effect on stability - consider a narrow rowing shell.
It is very wobbly and wants to capsize if you sit on it without any oars to stabilise you.
But as soon as you secure a pair of oars in the oar locks, it becomes a lot more stable - even though the blades are providing virtually no buoyancy as such.
Here the blades are acting a bit like the stabilising wheels on a child's bike.

Another example would be a 'stabilised monohull' - it could be described as a trimaran, but it only has very small floats on the outriggers, in comparison to the buoyancy of the main hull.
This paper by John Shuttleworth helps to describe the concept.
https://www.john-shuttleworth.com/p...eakindly-Fuel-Efficient-Vessel-Web_Part_1.pdf

 

..... and, above all, as long as it is perfectly watertight.

 

Have you looked at skiffs? https://image.made-in-china.com/2f0j00geMisOtKHUuE/14FT-All-Welded-Aluminum-Skiff-Boat.jpg

 

I have looked at skiffs. As well as tenders, dinghies, prams, currachs, coracles. and possibly others. The list of candidates is short if you have a ~150 lbs upper weight limit. There are a few composite boats, but they are all significantly more expensive.

For commercial offerings with the weight limit and, say, a $10,000 maximum budget, the design becomes a question of allocating some amount of aluminum.

The hulls are either 0.08” or 0.063”. If lateral stability is important, the material allocation drives the design toward wider and shorter.

The goal is a boat to putter around small, calm lakes, and do a little fishing.

A very slow, short Jon boat is the solution that I ended up on, understanding that every design decision reflects a set of constraints and compromises.

I am open to alternatives, but not ones that ignore the constraints.

 

Very interesting. It is remarkable how non-linear some of the factors are.

My decision that slowness was going to be a ‘feature’ for my boat, given that it will be lightweight and electric, was driven by speed-range curves provided by EPropulsion, an electric boat motor builder. The range at the bottom speed is more than 10x of that at the top.

ePropulsion - Spirit 1.0 Series https://www.epropulsion.com/products/electric-outboards/spirit-1

 

Hi, smallite! Long hulls will not be an advantage at very low speeds because they usually have a greater underwater draggy surface area, compared to square or circular Hulls.

What boats have you operated in the past and what are your pros and cons about them have you can incorporate in your selection? Will there be more than one person on board , and how much Deck / carrying weight capacity do you need? How important are seating, shade and standing comfort? The older you get the more you will need some blockage from a blazing sun, something with a comfortable seat back and Maybe a stand-up leaning bar. The type of fishing that you do can also influence your boat choice, for example, is it trolling, anchor and wait with baited hooks, fly fishing, etc? Some fisherman don't like aluminum boats because of the noise Factor caused when moving around or dropping something, it's louder compared to some other materials.

Here's a company that makes different rugged boats, sized down to the one person size- meets your criteria, if you haven't seen it already,

One-Man Boats https://pondking.com/collections/one-man-boats

Pontoons are my favorite configuration when there's more than one person, they give the stability of a Jon Boat with a potential for high efficiency and speed, depending upon how the pontoons are designed. Rugged inflatable pontoons can be used if a very light weight is needed. I'm a senior citizen, and have an assortment of different boats collected over the years; my favorite over the last decade has been a customized go anywhere e-powered Float Tube, weighs 30 lb with propulsion system, water, fishing gear, snacks, and spare parts

 

Hello portacruise, thank you for answering.

I have owned and used a number of boats, mostly sail or paddle powered. I used to rent a trolling motor-powered Jon boat periodically. It was memories of a small inflatable with a very small outboard that got me interested in a small boat.

I will be puttering with my wife, and don’t have need for much cargo capacity or deck space.

A bimini top is in the plan!

My original thought was a small pontoon boat, but I don’t want an inflatable, and I couldn’t find a rigid pontoon boat that was light enough.

I spent a fair bit of time on the Pond King site, and love the rotomolded coracle, but they are too small, while the 2-person pontoon is too heavy.

I do all kinds of fishing - mostly casting and retrieving.

 

Lightest one I've seen, but have never used one. May be able to do without a trailer.

https://plasticboats.com/specs-details/

Whitewater grade inflatables excel in rivers, bouncing off rocks and remaining afloat despite taking on water, that's where I do most of my exploring. Probably most ocean emergency survival rafts are inflatable. Of course they have their drawbacks, and they're not for everyone.. there's also RIB, kind of a hybrid, but might be too heavy and expensive.

 

Interesting little boat - like the other two options, made in British Columbia. I will see if I can find more on it.

 

I have a 12 foot wooden rowboat (that I built) that is about the same dimensions as what you are looking at. Yet it weighs only about 80 lbs. It does not have a squared off bow, like a Jon boat. I use it mainly for fishing and have an electric trolling motor by WaterSnake, which powers it faster than I can row it, but certainly does not plane it. I used to have a 2hp johnson that would, full throttle, move it about 7 mph, but defintely not plane it. A bigger outboard would have, but would have weighed too much for a little boat. You talked of standing up in a ten foot boat. I suspect you're going to get wet. Make sure you and your wife wear your lifejackets. I would never stand in my boat. I cast sitting down. It's not hard to do. If you insist on standing I would suggest you get a bigger boat, or one of the wider catamarans or pontoon boats. Yes they weigh more, but it's safer and roomier, and can take a bigger motor and they are more stable.

also. Recreational boat are required to have a capacity label (not just in the USA but most countries.) I suggest you check it. See how many persons and total load weight the manufacturer recommends, and what HP it is rated for. If you are going to use an electric motor, they are rated in watts not horsepower. 1 HP equals about 735 Watts.

 

I had one of those, forget how long ago. It only weighed about 50 lb back then and didn't have the front seat, IIRC. Very easy to row, but every stroke was a steering stroke whether you intended it to be or not. I fixed that by building a retractable stabilizer that bolted onto the motor mounting plate; it looked like a rudder but didn't turn. Absolute necessity if you didn't want to waste half your energy on course corrections.

Very susceptible to rolling over; I had a couple close calls before I learned to keep my CoG exactly centered.

It carried way surprisingly well for what it was, and I liked rowing it except for the part about looking over my shoulder all the time to see where I was going, which was why I sold it.

 

Maybe the previously mentioned collar or small floats would help with stabilization and allow standing up with this very tiny boat? Maybe they could be built to swing/fold in to the boat sides when under speed to reduce drag.. No way to tell without trying it, I guess.

Going backwards can be a pain in the neck, from all the twisting around to look behind you, on a float tube, ha! I improvised with a couple of bike mirrors attached to Alligator clamps and clamped to each side which can be reclamped or moved for the best viewing position. They are on a tether so they are not lost or damaged if they get knocked off when at close quarters. There's no pulsing or coasting between Strokes when using a motor, so my FT runs straight. Of course, these ideas may not work for everyone or for that particular small boat.

 

For what it’s worth, this type of boat is a staple for stillwater flyfishing in British Columbia, with hundreds, if not thousands in use.