Electric Boat Build

[Ulu]

I bought this old Fiberglass scow about 25 years ago, and I’ve done quite a bit of fishing at the local lakes in it. The hull is a ‘76 Olympian tri-hull, 14’-6” overall, unpowered.

It came with a 40 horse Evinrude Lark, circa 1969. The hull and trailer were spotty and the engine needed complete rewiring. I refurbished the whole boat over 20 years ago. I did a lot of work on the hull & Painted it with Starthane polyurethane rubber.

Anyhow it did not become an electric boat until I became semi-retired about five years ago. This is how it looks today.

All the project photos are on my desktop and I’m going to load them up here in the kit car category. There’s nothing else that comes even close.

More to come.
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SS100 kit kar
1600cc DP

[Ulu]

So I bought this with a 40 hp Evinrude Lark. It had electric shifting and magnetic clutches that wore out. But on a 30 HP rated hull it was a beast in action. At top speed the boat could not turn right due to counter torque. I would have to relax the throttle. Here I am just adding fresh paint.

You can see the live wells installed by a previous owner. Pedestal seats in tandem, and plastic gas tank. (all gone now.)

The only video of the power boat in action with the old Evinrude power. It's pretty fuzzy. I shot the vid with one hand and the other on the steering.


Link


As a 2-stroke, this boat would hit 25 knots or more, but now it is only good for 6 knots max. I don't mind. I don't have to race to the fishing where I go. I really like the fact that I'm not chasing off the fish or putting oil and fumes in the water.

In the photos of my first post above, you can see the 40lb thrust front trolling motor is on the boat in one pic, and off in another. I foolishly thought the boat would go faster if I ran both motors. It didn't matter enough to notice.

To save weight I removed it and its battery. That red platten at the bow is epoxy-coated 1-1/8" plywood. I added it to reinforce the bow and support the trolling motor when this was a gas boat.

The 40 hp took it's toll in weight and the transom started to warp. I let in some steel tube braces into the transom, epoxied them in, and fiberglassed over it all.

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SS100 kit kar
1600cc DP

[Ulu]

Goodbye Evinrude! Actually it went back on, right after the transom work. But eventually it went to the boat junkyard outside Clovis CA. I built that hoist for my dad when I was a teenager in 1973.

The first incarnation of the electric boat was the 24volt X-24v which had five 12v batteries. One supplied the 40lb motor in front, and 4 supplied dual 24v 50lb thrust Navigator motors astern. Power cables I soldered from new welding cable, and wires run thru the steel tubing.

This is all very temporary and experimental.

This was a very experimental design and proved fast on still water but unsteerable in even modest waves.

I got those two motors free and they still run great. I soon replaced them with a salt rated 112lb thrust Minnkota.

Here the boat in in transition. I have added wood rails to reinforce the gunnels and a plywood rear seat deck. A lot of epoxy filler and fiberglass was also added to reinforce the gunnels. You can see the old live well covers. There is no middle seat yet.

Construction details of the tiller without breakaway motor assembly. The motors would tilt up, after breaking a weak safety tie, if they struck a rock. This was all EMT, but reinforced at the joints with doubler and tripler sleeves.

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SS100 kit kar
1600cc DP

[Ulu]

One reason I bought the VW kit kar is that I do fiberglass. I learned it all fixing this boat, and remodeling it three times over 25 years. It has extensive reinforcement and repair inside all the floatation chambers. The keel got lots of new cloth after I cut out old damage and patching.

Midnight fiberglass R us. Old foundation drawings from the new Central highschool mask the paint and cover the concrete.

I built the gunnels out wider and deeper and thicker. This took a lot of thin layers to make it tough. I only had 4' long cloth so there are lots of laps. It is built up much stronger amidships.. I also thickened the gunnel at each mount for the wooden rails.

Here I build it up fast with uncured layers. I will trim the ragged edge with a scissors, while it is still soft.

I added a plywood casting deck up front. You really couldn't stand on the forward floor before this.

Here I build the doors and frame. You can see the gunnels all sanded and painted now.

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SS100 kit kar
1600cc DP

[Ulu]

I used mostly poplar wood for the deck framing. It sits on redwood sleepers over the floatation chambers. It took lots of glue & sealant, with paint and man-made sand for grip.

Here the casting seat is installed. I raised it on a drum made from oak offcuts.
There's my lovely wife having fun. It's almost too tall for her, but I am 10" taller. It's made for me. You can see the doors aren't finished and there's no middle seat. The batteries are all in the stern here, and they weigh it down too much!

When I added 6 batteries and the extra weight of the decks etc, I had to reinforce the trailer too. It went from 2 rails to six. It got 2 new rollers and 2 crossmembers from unistrut. It got all new carpet & I made it scratch-proof & visible, with foam padding and colored duct tape.

This new 112 lb Minnkota was made for a tall sea-going boat, yet has a tiller.

If you want to make your wife mad, buy a thousand dollar motor and let her see you cut it up.

Off with the used 'Gators, and on with the new Minnkota!

The boat now steers well in any conditions, and goes about 6 knots now. Previously it could only manage 4.8 knots in calm water.
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SS100 kit kar
1600cc DP

[Ulu]

Hoisting the boat for trailer repairs.

The mid seat is plywood and poplar. All the wood will be coated 3 times with Minwax polyurethane. I scuff sand between coats to prevent peeling.

You can see my emergency pole holder, as well as the neat wood outrigger mount points on the gunnel.

Initially I had six 12v batteries: about 330 lbs. total.

Here's the motor, shortened, and in the stowed position. It cannot turn on when stowed.

Part of the speed increase was a big 3-blade prop.

I found I can explode these props if I abuse them in reverse. They don't work well in reverse.

This was my second control box, partly made from bits of the first one.

The ugly green plastic tray covers the cables and holds random gear while underway. There's my old Humminbird sonar, phone charger, and voltmeter.

At that point the rear motors had no speed control. You could switch the motors on or off independently. The front motor was still necessary for trolling, as it had variable speed foot control.
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SS100 kit kar
1600cc DP

[Ulu]

I never broke a prop with the Evinrude, but they weren't plastic either.

Plastic prop exploded from running hard in reverse.

New high-zoot Humminbird with the old.

The new switch box. The ugly green tray is replaced by one from maple and mahogany. These were made from bits of my old kitchen. The switches for lights, USB ports, etc are not installed yet.

Here is my wife in the boat with the top up. It was sitting a bit low from battery weight.

I have removed 3 of the batteries, plus the front motor, to reduce weight. I thought I would lose a lot of range, but I find 3 batteries will troll around much longer than I want to fish on a day.

I reduced my high-speed range, but I don't run flat out much. 80% power is only 50% of the draw at 100% power, so I can be frugal.

But what if it quits? I can sail it.

Every lake here has good afternoon winds. That's when we quit fishing
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With a good breeze, I can drop the bimini top forward, take the backstays in hand, and control it as a sail: raising and lowering it with the stays.

The dead motor makes a reasonable rudder and tiller, so steering is easy. If the prop has enough current to even turn slowly, the drag is very little and if it runs at half speed, the boat easily sails as fast as it runs under power.

It has then about 30 sq ft of canvas. Even in a light breeze it will push the boat along well.

We ran low on a trip to Huntington lake, which is the nation's #2 rated sailboat lake. It gets a spanking breeze from the ocean in the PM. I was able to sail and tack against the wind far easier that I thought would be possible.
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SS100 kit kar
1600cc DP

[oprn]

Nice job!
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Our cars get old, we get old but driving an old VW never gets old!