ALUMA-JET- Duracraft 1648 SV Jetboat Conversion

A little additional reinforcement around the jet unit, to guard against any rock strikes, should I decide to venture above the fall line:



These are 1/4" aluminum plates, that bolt to the existing box around the pump that is also made of 1/4"....basically extending the unit on the sides (something I should have done to begin with!)



And then there's the ride plate on the bottom, made of 1/4" aluminum. I would have extended it farther, but the clearance to the reverse gate would have been really close, and it might have interfered with thrust power in reverse.



Needless to say, I made it as bulletproof as I could. Turns out that was a good thing. Last week at the ramp, I pulled a good one, the ultimate idiot move, in fact.

Since the bottom of my boat is coated with Line-X, it no longer slides very well on the carpet bunks. So, I went over the top of the bunks with Trex boards, which are very slick.

Normally when I launch at the ramp by myself, I unhook the bow strap and safety chain, then hook my 25 ft rope to the bow eye, and secure it to the winch post of my trailer, and I toss the pile of rope on the bow, so it pays out. When I back down the ramp into the water, the boat will float off, and I pull forward, which pulls the boat up to the ramp, then I unhook the rope, set anchor, and go park the truck.

Even with the TRex boards, I have been doing it like this, without an issue. But for some reason, there was an issue, and I think you can guess what it was. #-o Yes, when I got about halfway down the ramp, the next thing I saw was the bow of my boat straight up in the air, with the a$$ end of my boat firmly planted on the ramp!! :shock: :shock:

I quickly hopped out, and winched the boat onto the trailer enough to lift the transom off the ramp, which, fortunately, is just hard-packed oyster shells, and not concrete. Then I backed it down in the water. Once I got into the boat and cranked up, I fully expected there to be no steering or reverse, but to my surprise, they worked. I ran around for a bit, but I noticed at speeds above 8,000 RPM, it wanted to porpoise.

After hauling out, I did a damage assessment, thinking it was going to be horrible. Once again, to my surprise, the only damage was the ride plate, the back end of it had gotten bent upward from hitting the ramp, but it most definitely served its intended purpose of protecting the steering nozzle. I think the side plates probably helped a little bit, too, being vertical, not horizontal, they were able to hold a lot of pressure.

In any case, I unbolted the bent ride plate, and used my press brake to straighten it out. Then, I decided to weld that piece of 1/4"X1" aluminum flat bar down the center, as a stiffener, in case anything ever hits that plate again. Hopefully it won't, but it's sure nice to know that added protection served its intended purpose! I would say it passed the torture test....with flying colors.

This, in conjunction with the improved stomp grate, as well as the Line-X, makes me feel a little more confident about venturing farther inland.

Thanks for sharing that story, last year I forgot to put the drain plugs in, the bilge got a good rinse needless to say.

Your mishap is a good reason to overbuild these rigs - ya never know what is going to happen!

I am interested in how that new skeg affect your handling. I would think it should help you stay straight.

Yeah, like I said, I am SO glad I decided to go ahead and reinforce the area around the pump with all that plate. That probably saved me a busted steering nozzle, thrust nozzle, reverse gate, and the steering and reverse cables. The plates worked so well, that the boat itself never touched the ramp, there wasn't a mark anywhere on the bottom edge of the transom. That really surprised me.

Needless to say, if it can survive that, I think it will be OK if it bumps a rock in the river (at low speed, not wide open)

As for the keel on the bottom of the ride plate, not sure if that will improve steering, but I will know when I do some running around with it. I still don't think it will be enough to keep the stern from walking side to side when I am waterskiing behind it, that's just the nature of a jet boat. But I'm sure it will probably help it track straighter under normal operation.

Hey man, havent visited site in a long time!
Just wanted to wave my hand and let you know I still would like to make a jet-jon out of my 2472 Sea Ark, bot I know it would take a large engine, though I dont care about going fast. Would appreciate all ideas and any advice you could give me.

2472 would be a cruise ship!

My advice is don't go cheap on the engine.

I did for 1st engine & then went back & replaced with 4 stroke yammie (PSG was role model on that).

4 stroke yammie is 3X better than the 2 stroke - less fuel, vibration, noise.

Take your time & search CL, rental places sell at the end of each season.

Good to hear from you again, mmf!

The specs say the 2472 sea ark weighs about 950 lbs, just the dry hull weight. Then you have to account for weight of engine, fuel, battery, persons on board, gear, additional decking/modifications. A boat that size, especially with the wide beam, would be a good candidate for twin engines, or if you're going with a single engine, you need something big, like the 1800cc Yamaha 4 stroke engine.

It's not just a matter of having enough power to go fast, it's a matter of having enough power to push the boat without over-lugging it. Kinda like putting a 7" grinding wheel on a 4 1/2" angle grinder. Yeah, it will turn it, but it's putting a lot of undue strain on the motor and will shorten its life.