Hydro Thunder Manual
Francoise Witsell
The Insane Boats Classic Thunderboat is one of only a handful of fiberglass round-nose hydros available on the market. And for those faced with the decision of building one from a box of laser-cut wood or installing a motor and hardware on a built-up hull, the choice is usually an easy one. I've built a few wood kits but the ease of assembly that a fiberglass boat offers wins hands down in my book. The Insane Classic Thunderboat is just such a boat - easy to finish and even easier to set up. In fact, a few evenings of work can have you ready for the weekend and winning races to boot.
The monstrous brown box arrived at my door containing the hull, cowl, radio box, and assembly instructions. I opted for all the additional Insane Thunderboat hardware which consisted of the turn fin, strut, rudder assembly, classic driver, steering wheel and gauge cluster, and transom exhaust package. In addition I got the Insane Dominator pro pipe with header and flange. The pipe comes as a zero band with a steel header. It uses a clamp with no o-rings to eliminate water leaks and burned o-ring issues. It also features a no-leak header with offset bolts that make removing and installing the pipe a lot easier than vertical bolts.
I went with a 500ml gas bag instead of a hard tank for this build. The objective is to place the tank off to the left in front of the engine. There is plenty of room on the left side of the engine rail and the sponson to fit any type of fuel container, but the actual mounting part is a little more involved. I epoxied a wooden block to the inside of the hull up near the nose as an anchor for the bag. Before I installed the block, I drilled a hole and threaded a bolt in with a large stainless washer. That way, all you need to do is epoxy in the block, slide the bag up to the left front and screw it down tight. The washer will act as a clamp and prevent the bag from moving around. Now, drill a hole through both engine rails in front of the motor to run the fuel lines. I didn't bother to secure the front of the bag because the fuel tube, making a 90-degree turn from the outlet and through the engine rail, holds the bag down and prevents it from bouncing around.
The cowl comes as two separate pieces, and from searching around the forums and looking at the races, I've found that everyone mounts their cowl in their own unique way. I chose to attach the two pieces together using stainless bolts and create a one-piece cowl and use rubber cowl locks from TopSecretBoats to secure it to the deck. One lock at the front of the cowl and two at the transom hold it securely in place even during a blow-off. When mounting the driver, I used some industrial Velcro so he can bail out if the boat stuffs hard. Even though the drivers are durable, I've seen them crack as they impact the water going 50+mph. Its best to have them break away. Since the interior of the hull is exposed due to the cowl design, it isn't necessary to cut any holes in the rear of the cowl, although doing so wouldn't hurt.
In order to balance the boat, Insane Boats recommends adding 12oz of weight to the right sponson. I made a cube of lead with stick-on weights and taped it together, then added some Velcro to the bottom and another piece on the inside of the sponson. Make sure to use industrial Velcro if you use my method as regular stuff won't hold the lead for very long. I ran the interior piece of Velcro the length of the sponson so I could move the lead forward or aft if needed to balance the boat. Placing it 2 inches from the back of the sponson seemed to do the trick on my hull.
With the engine mounted, install your pipe and drill a hole for the transom exhaust exit. You're on your own as far as securing the pipe, and I used a stainless rubber clamp bolted to the engine rail, which is available through McMaster Carr. The offset no-leak flange is a nice addition to the Dominator Pro pipe. There's no need for close-quarters hex wrenches anymore because both fasteners are exposed and easy to get to. I set the pipe at 11" from exhaust window to the band as a starting point and so far it's been right on...no need for adjustments.
Now that the hard work is done, make sure to stuff the hull with pool noodles just in case she fills with water. Don't forget the cowl too - it will sink like a brick without it. Now is the time to apply your paint and decals. I went with the Black Cat Fireworks logos because, well, that just one mean looking cat! One coat of black on the deck is all I needed and the whole boat was finished off with some automotive pin-stripes.
To set the classic thunderboat up for its maiden, I angled the turn fin to 20-degrees and made sure the bottom of the fin was parallel with the bottom of the boat. The strut was given 1 degree of negative and set at a depth of 1 3/4" from the bottom of the transom to the center of the prop shaft.
The prop used was a PropWorks West #395 Classic Thunderboat. I would highly recommend this prop as it is perfect in every way. The finish is spectacular, the balance was right on, and the blades were very sharp. This prop was designed specifically for the classic thunderboat and has proven to be a great match for the Insane.
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