Smaller pontoon boat- EC24 or PC20 but shorter?

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Fred in Wisc
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Smaller pontoon boat- EC24 or PC20 but shorter?

Post by Fred in Wisc »

Apparently it's 14 below zero in hell today and flocks of swine are filling the skies somewhere. My wife, who almost always prefaces the word "boat" with "stupid", actually told me she wants another boat!

After some excited questioning from me, we determined she'd like a small pontoon boat with electric power. Something suitable for a few miles of cruising around our lake (500 acres, mostly shallow and weedy) at putt-putt speeds with a few friends, giving the kids a platform to swim off of, etc. She's currently using a paddle boat, but wants something larger and powered that she can just hop in and go whenever she wants. No maintenance or fooling with motors is very important, so I'm thinking electric drive with solar charging and a tiller steer electric trolling motor for simplicity. Speed's not a priority- quiet and no maintenance on her part is.


I'm thinking a deck area of around 8-10' long and about 7-8' wide, partial roof to hold solar panels for charging. Lightweight build with minimal furniture. Trailering is not important, it'll go a mile to the boat landing at the beginning and end of the season (Or I'll get a few big guys and we'll just drag it up on shore for winter). It'll probably live on a lift during the boating season. I'm thinking typical load would be 2 adults, max would be 6 or so.


I like the EC-24 but it's too big, I can't dock something that long conveniently and she doesn't want a "big" boat, she wants a cute little boat. I'm thinking more like 14-16' overall. Is there a straight section in the pontoons that I could remove, or scale them length wise only to get to a dockable size? Or would it be better do do that with a PC20?

Fred in Wisc
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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by Fred in Wisc »

Since weight will be a concern, I'll address the propulsion system. I'm thinking of a 100watt solar panel with a controller, 2 80-100ah 12v batteries (or maybe one 80-100 ah and one smaller 35ah unit). A 12v trolling motor around 40-50# thrust (bigger if I need, but the 40-50# are pretty inexpensive and run on 12v rather than 24v). I'd run a 1/2/1+2 battery switch, running on 1 battery and having a second as a "get home" unit if the first is depleted (no power to get home = unhappy wife = unhappy me)


Weights- batteries 100-200#, solar about 15#, motor about 20#- total 130-250 let's say.

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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by Jeff »

Fred in Wisc, I sent your thread to Jacques a few minutes ago as I believe he will be able to provide you the best, most thorough response!!! Jeff

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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by jacquesmm »

Scaling is a problem. Please see this to have an idea of the problem:
https://boatbuildercentral.com/wp/suppo ... -plans.pdf

You are confronted with some conflicts: a cat smaller than the PC20 will not have sufficient buoyancy to support 4 or 5 persons. Plus, there is a solar charging problem. You need a large solar array area.

An EC24 scaled down to 14 or 16' will be very heavy for it's length and will not have sufficient capacity.
In labor, a scaled-down boat would cost just as much in labor and almost as much in supplies.
The PC20 as designed would be a good candidate.

Solar power is fine for a boat that does not need a long range. Two years ago, I did the math for the wide version of the PC24 and the max. output was about 3 KW in direct sun. That barely moves the boat in no wind and now waves. The PC20 roof area if fully covered is much smaller. I estimate 2 KW max. in full sun. You need a good battery bank.
There is a solution: have a covered boat lift or boathouse with many solar panels on the roof. Plug the PC20 batteries in when the boat is not sailing.

That should be easy to use: plug and unplug the solar array. Leave a Torqueedo motor of about 5 HP (3.5 KW) permanently attached on the transom.
All that you to do is operate the boat lift, unplug the solar array and you go.

When estimating the cost, look at the whole project: solar array with regulator, deep cycle batteries and electric motor. All that cost much more than the boat.
The little $ 750.00 2.5 HP I use on my dinghy suddenly looks real good.
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Fred in Wisc
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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by Fred in Wisc »

Thanks for the input, I was looking at a much smaller electrical system but if it not going to drive the boat adequately, I'll need to do some pondering......

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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by jacquesmm »

Count on about 15 watt per square foot. If you have a roof 8' wide and 16' long = 128 ft2. That is very optimistic but let's try.
128 ft2 by 15 = 1920 watt = 3.5 HP in full sun at noon.
It is very simplified but gives you an idea.
An 8x8 array is reasonable. it will produce 1 KW in full sun. Enough to charge the batteries for the weekend.
A solar array cost about $ 3.00 per watt. In the case of the 1 KW above = about $ 3,000 for the panels. At least that much in deep cycles batteries.
Jacques Mertens - Designer
http://boatbuildercentral.com

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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by jacquesmm »

Please do not misunderstand, I like solar in some cases. I had my first solar panel on a boat in 1981. I still have a solar panel on my camper and I have a solar water heater on my house roof.
Solar panels and batteries are becoming more efficient every day.
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Fred in Wisc
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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by Fred in Wisc »

I was thinking about 100w of panels (around 8 sq feet) for each battery (2 on board). In an average nice summer day, figuring 10 hours (out of 14 or so in summer) of decent sunlight, and a 30% derating for inefficiency, that's around 700w per battery daily. Fits on a 4x8 roof section approximately. Cheapish Chinese versions with controller are about $150-200 per 100 watt system. There's 2 independent systems for redundancy in case they aren't super reliable.

50# trolling motor is around a 50a draw at full power, so about 600-700w. Should be able to power that for approx. an hour on high from each battery, each day. If it's rainy and nasty out, it will charge a lot less, but she won't use the boat in that kind of weather anyway.

I've got a similar size troller on my 16' aluminum V, which is a lot heavier, and it moves around fine with a big outboard on back and a few passengers, even in light to moderate wind. I figured that would push a more efficient cat type pontoon around pretty well, especially if I keep it nice and light.

The lake is about a mile and a half long and 3/4 mile wide, generally the "loop"around it for an evening cruise is about 3 miles (not back into all the bays and such), so we don't need a lot of speed or range. One time around per battery would be plenty. 3-5mph area probably.

If the power requirement for that is more like 3.5kw, rather than .6kw, you're totally right- the cost of the power system is a game changer. Looks like I have underestimated the power required.

I'll consider some other alternatives, or see if I can get a higher build budget.

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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by fallguy1000 »

There are some simple facts Fred.

Electric is HIGHER maintenance; not lower than a gas outboard.

A good gas outboard about 25-30hp two stroke is nearly bulletproof. Yeah, it requires mixed gas, but many of those engines run 1000 hours before they need a plug change.

That is 1000 hours of running with 0 maintenance.

There is not a single electric motor, solar panel, solar controller, battery setup that can offer 1000 hours of running without maintenance. Not one.

Both boats need to be pulled for Sconi winters.

The electric boat, let's say you put 4 hours a weekend on the engines and you run it for 26 weeks. That is 100 hours a season. Your batteries will only survive for 10 years under the most exceptional conditions and care. And 10 years on solar panels is sort of a roulette game.

I am sorry to burst any bubbles, but if you want low maintenance, electric ain't it.

If you want ultra quiet, electric is it.

Kind regards.
My boat build is here -------->

viewtopic.php?f=12&t=62495

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Re: Smaller pontoon boat- EC24 or PC20 but shorter?

Post by fallguy1000 »

Another problem with batteries is weight. Cheap batteries are especially heavy. In the Skoota build, I have a consultant for the electrical. I set a maximum battery weight of 450 pounds and he recommended the best battery for me. The cost is really scary. $4500... The comparable number of batteries I'd need in high end marine batteries is 450-600 pounds and this is not to run engines. That 450 pounds translates to a couple of passengers...I really like the concept of the electric boat, but they are really expensive versus gas outboards..
My boat build is here -------->

viewtopic.php?f=12&t=62495

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