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VIDEO – Sponson Demo

This land-based video takes the HydroCar from LAND MODE to WATER MODE by demonstrating the articulating sponsons. Watch as it literally transforms itself from an automobile to a tunnel-hulled watercraft.

 

VIDEO – Water Test One

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When we first launched the HydroCar, it was pretty obvious that the nose lacked buoyancy.

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Floating motionless in the water, the craft sat slightly nose down, while the prop was actually angled up and sticking almost half out of the water.

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We lowered the trim about twelve degrees so the prop could get a better ‘bite’ in the water, but when we brought up the RPM and began to pick up a little speed, the angle of the prop drove the nose down even farther.

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This, in turn raised the prop nearly halfway out of the water.

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As you can see by the ‘rooster-tail’, it was putting out a lot more power than it could use – because the prop couldn’t get any ‘bite’ in the water.

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Dropping the trim even more to give the prop a better ‘bite’ drove the nose in even farther and made everything worse.

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Notice in the video how the nose is forced farther down into the water as the speed is increased.

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We were plowing the water in front of us, instead of rising over it…

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Plain and simple – we needed more buoyancy in the nose.

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Modifications after Water Test One:

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The middle and rear underside wings were removed to provide a less-interrupted water flow to the prop.

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The front wing was replaced with a much larger, upward angled wing for additional buoyancy.

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The area under the main hull that made clearance for the middle wing was filled in – also to add some additional buoyancy.

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An auxiliary battery was added to the rear deck for additional cranking power and weight transfer.

 

VIDEO – Water Test Two

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With the added buoyancy in the bow, the HydroCar sat a little bit better, but was still a little lower at the nose.

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The prop went a little deeper in the water, without lowering the trim as far – but still not nearly enough.

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There was still way too much ‘rooster-tail’ as the RPM was increased.

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It went a little faster, which showed us that we were on the right track.

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Modifications after Water Test Two:

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We decided to take the front-end buoyancy issue very seriously this time, so a huge, removable front wing was fabricated and added to the nose. It is attached at four places, and takes about fifteen minutes to install or remove.

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The new wing not only added over three hundred pounds of buoyancy to the nose, but also enhanced shape of the craft’s front end.

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About three hundred pounds of the floatation also foam was removed from the rear sections of the side sponsons.

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This gave us a total weight transfer of about six hundred pounds...

 

VIDEO – Water Test Three

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For the first time, the HydroCar sat in calm water with the nose higher than the rear.

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The prop only needed to be trimmed down a couple degrees to be completely submerged.

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This time the front end of the HydroCar actually raised when the RPM was increased.

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The prop was still creating a huge ‘rooster tail’, so we lowered the trim to compensate, but still couldn’t get the necessary ‘bite’ to get it up on plane.

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When adding the trim angle to the angle of the craft, we found the prop was still angled downward around twelve to fifteen degrees – resulting in a less than optimal angle for forward motion.

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Modifications after Water Test Three:

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We went back to the dock and added four fifty-pound sandbags to the rear deck.

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We also switched over to a four-bladed prop with a greater pitch.

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We were hoping that these modifications would result in a better attack angle for the prop with less cavitation…

VIDEO – Water Test Four

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These quick modifications resulted in less cavitation and a bit more speed, but we still couldn’t get it up on plane.

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It almost seemed that the HydroCar had added some weight on the last two launches – and indeed it had.

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At this point, we thought the main problem was still the prop, not realizing the rear wheel wells were not self-bailing adequately.

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Modifications after Water Test Four:

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Studying the videos and calculating the latest modifications, it was obvious that we had gone too far with the weight transfer.

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To understand the problem that we had created, the following is a little design information:

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The HydroCar’s wheel wells are covered on the bottom with sliding panels similar to the landing gear doors on an aircraft – but they are not watertight.

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Water enters the wells through the axle openings as well as around the bottom panels.

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To drain the water out of the wheel wells, each well is designed with a trough in the rear to self-bail any water that might accumulate, as soon as the craft begins to move forward.

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The front wheel wells had adequate-sized troughs, but the rear wheel wells did not.

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On launches three and four, with a lot of added buoyancy in the nose, the front wheel wells had self-bailed – but not the rear ones – so they had actually filled with water.

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This resulted in the craft dragging over six hundred pounds of water along with it (inside the rear wheel wells.)

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Add to this the removal of three hundred pounds of floatation foam from the side sponsons, (which was now filled with water) and two hundred pounds of sandbags – and it was almost like we were dragging an eleven hundred pound anchor behind us!

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So…

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The troughs in the rear wheel wells have been opened up to accommodate the additional water flow, thus enabling the rear wells to self-bail as they were originally designed to.

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A keel-cooler was added under the craft to aid in engine cooling while in WATER MODE.

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The electric / hydraulic marine power steering system was changed over to an engine driven pump to reduce the current draw on the electrical system.

 

The HydroCar is now ready to go – but the weather in upstate New York is prohibiting any additional Water Tests until spring.

I’ve recently had a lot of input from several boating experts and most of them feel we’ve got it just about everything ‘dialed-in’ except for the prop.

We still need to find a prop with just the right combination of diameter and pitch, combined with the proper number of blades, so the HydroCar can optimize its performance.

Once it’s up on plane, it’s going to be one Hell of a ride!

 

 

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