ALUMA-JET- Duracraft 1648 SV Jetboat Conversion

[PSG-1]

Ranchero50 » Today, 14:21[/url]"]Should be a fun project without some of the hickups from doing it the first time. Who knows, you might make enough profit to take the wife out to dinner.

Good luck and post everything. This site is a repository for this type build.

Will definitely post pics and details once we get started. I'm thinking the same thing, about no glitches on this build, since my boat was an 8 year work in progress. Truthfully, though, the biggest issues I had with it the first time around was with that POS tigershark engine, I think the XL1200 pump was putting too much load on that motor. But as far as how everything was put together, like the structural work, motor mounts, etc....no issues. Just little things, and of course, fine tuning and constantly adding improvements.

The 4 stroke has more than enough power to turn that pump though, and as such, I have had zero issues with the reliability of my boat since I went with that motor. Only issue is the no-wake switch not wanting to work sometimes, but then, this is common, even with these engines in the factory jetboats.

 

[PSG-1]

Well, almost a year later later, and I've finally managed to recover my money from that VX110 and XL1200 pump that I had bought to do a jet boat build. That deal fell through, then there were a couple of other offers that also fell through.

I was then considering building a small New Zealand-style jet boat for myself, but then I didn't expect to nearly die from encephalitis this past February. :shock: Yeah, I would consider being on a ventilator for 4 days as being 'dead' And then another 2 weeks in supportive care.

Having gone through that, I now have too much self-doubt to be building jet boats.... or accepting job offers to go to work for state agencies like I had been considering, before that life-changing event. Fact is, it caused brain damage. I've been recovering from it, and gaining back some of what was lost, but I don't think I'll ever be to the point that I was before the encephalitis.

In any case, I was able to sell the engine and pump back to the guy I had bought them from. Sure hated to part with that engine, because it was so clean and new-looking. But the jet ski was just sitting in the corner of my backyard for the last year.

That said, the Aluma-Jet is still running strong. The 4 stroke FXHO engine is the perfect match for the boat. Should have done it like this to begin with!

 

[painlesstom]

Oh man, I'm sorry to hear that! I'm glad you are still here to tell your story and that you were able to recoup some of your investment from the deals that fell through. I will keep your continuing recovery in my prayers! Keep your chin up and enjoy that Aluma-Jet until the day comes you are able to start building again.

 

[fender66]

Glad you're on the track to better and still able to get on the water!

 

[PSG-1]

Thanks, guys! It's been a tough year, but I'm definitely in better shape than I was in February, and improving as the weeks and months go by. The good news is that I did manage to quit smoking, so, at least something positive came out of the ordeal. That, and the fact that my Blue Cross insurance covered nearly all of the $46K hospital bill. Of course, I've paid premiums to them for the last 20 years, so, I guess that about evens it out. :mrgreen:

 

[smackdaddy53]

I'm glad to hear you made a recovery bro. Life can sling some curve balls at inopportune times!
I picked up a 14 foot .125" aluminum hull the other day and I'm kicking around the idea of putting an inboard jet in it after seeing yalls builds...

 

[PSG-1]

Thanks, smack daddy. It was definitely a curve out of left field, for sure.

A .125" thick hull would be a good candidate for a river runner. Stout enough to resist bumping over logs, and maybe the occasional slide over a gravel bar. And .125" is plenty of material thickness to be able to weld it with no problem.

 

[smackdaddy53]

Thanks, smack daddy. It was definitely a curve out of left field, for sure.

A .125" thick hull would be a good candidate for a river runner. Stout enough to resist bumping over logs, and maybe the occasional slide over a gravel bar. And .125" is plenty of material thickness to be able to weld it with no problem.

I picked it up for $600. It was built in Louisiana by some oddball company but built like a brick sheet house. I may just fix it up and flip it.

 

[PSG-1]

If you do fix it up, be sure to post some pictures! 8)

 

[Capt1972]

Here's a shot of the starboard stern hatch. This gives access to remove the fuel tank, as well as some storage for another dry box. This dry box has some bottled water, food and other survival gear in it. Also, note the inline water strainer located on top of the fuel tank. I figure it's a lot easier to lift this hatch to check my strainer, than having to remove the engine cowling, and stick my hand down amongst all the razor blades (hose clamps) View attachment 6


This one shows the front of the engine. You can see how there is a 'bulkhead' at the front of the engine. The water has to be this high on the deck to flood into the engine compartment, and even then, because the cowling overlaps this bulkhead and there is a seal all the way around the cowling, that isn't likely to happen. because the round object right in front of the bulkhead is a cover with a strainer screen for a 500 GPH electronic bilge pump. Also contained in this area is the siphon bilge pump that hooks to the jet pump, so it is pumping whenever the engine is running.

View attachment 5
I set the engine back as far as possible by cutting the driveshaft shorter, but even so, I couldn't get it back that last 2 inches so the entire engine would be behind a bulkhead.



A shot of the engine from the starboard side. View attachment 4

On the 2 stroke design, both fuel tanks were located all the way to the rear. But, because of how the muffler comes off the HO engine, the fuel tank had to be located forward. As a result, the hatch for the fuel tank access had to have the filler neck hole cut into it, so, it is not a removable hatch like the starboard side, it is riveted in place. The vent to the rear is for the blower, and because the slot faces forward, it also acts as an air intake while underway. This was the location of the original filler neck for the port side fuel tank. When I moved the tank forward, I utilized this existing hole for the blower by enlarging it to 4" diameter.

The vent in front of that faces to the rear, and allows air to flow out. The only reason the forward vent is there to begin with is because of the height of the fuel pump, I had to raise my deck up about an inch or so to give clearance for the wire harness plug. If not for that, this vent would not be there.



A shot from the port side. You can see the driveshaft coupler guard, I fabricated this from some 1/8" aluminum sheet, bending it in my brake. I used yamaha's pre-existing bolt holes for their coupler guard to bolt a set of clips to, for the guard to slide down onto. Works pretty good.
View attachment 3


Although the cowling sticks up a good 6 inches higher than the rear reck of the boat, when you look at it from the side, it's not really that noticeable, and the 'High Output' lettering breaks it up, so it doesn't look as big (the lettering is factory Yamaha, for their SX230 jetboat)
View attachment 2



Here's a shot of the stern, that shows off the platform. The platform attaches with 4 bolts.
View attachment 1


A shot of the transom, showing the jet pump tunnel with the rubber skirting that acts as a sound baffle.

I guess I'm just missing it, where is your exhaust in that last pic? Is it the tube in the steering nozzle? Wouldn't that block some thrust?

 

[PSG-1]

You can't see it in the last pic. It's hidden by the rubber skirting around the jet pump. The exhaust outlet is between the jet pump and the 'box' that it is bolted into. The tube near the steering nozzle is what would normally be the 'enema' on a PWC. Instead, I have it hooked to a quick connect fitting, with a coil hose and spray nozzle. This way, I can hose down the deck of my boat, as long as I'm underway, so there's enough pressure at the nozzle.




In the other pics showing the engine, notice the large black hose that goes into the top of the jet tunnel, near the transom.


This is where the exhaust enters the box. The rubber skirting around the jet pump contains nearly all of the sound coming from the exhaust, and because it's exiting near the jet unit, a lot of the sound is also muffled by the aerated water exiting the jet pump.

 

[PSG-1]

Originally with the 2 stroke engine, there were reliability problems, which made me nervous to take the Aluma-Jet very far from home. Now with the 4 stroke, I don't give it a second thought to trailer the boat 2 hours from home, and go explore an unfamiliar stretch of water.

Anyhow, over the last 4 years since swapping to a 4 stroke MR-1 High Output engine, we've covered about 325 river miles on 7 rivers, comprised of the Lumber River, Great PeeDee River, Little PeeDee River, Waccamaw River, Black River, Sampit River, and the Santee River....as well as a portion of the AICW.



This year, I hope to cover even more new territory!

 

[painlesstom]

You should come check out the Altamaha. :mrgreen:

 

[PSG-1]

You should come check out the Altamaha. :mrgreen:

I've looked at the Altamaha on google earth, as well as a few pictures and videos of it, looks like it would be an awesome river to run. Reminds me a lot of the Santee River in South Carolina.

 

[painlesstom]

You should come check out the Altamaha. :mrgreen:

I've looked at the Altamaha on google earth, as well as a few pictures and videos of it, looks like it would be an awesome river to run. Reminds me a lot of the Santee River in South Carolina.

If you do make plans to make the trip, you'd want to come when the river stage is 6' or less for best scenery. All there is now near 12', are flooded banks and fast currents. Now if it would just stop raining.......

https://water.weather.gov/ahps2/hydrograph.php?wfo=jax&gage=dctg1&refresh=true

 

[PSG-1]

Thanks for the info. That's about how it is here. 6 ft on the NOAA gages seems to be the magic number for most of our low country rivers. Much less than this, and some of them become impassible, due to shoaling. I've seen google earth images when these rivers were in drought, and there were entire sections of the river that were nothing but sand. But if the gages are reading well over 6 ft, all the nice sandy beaches and gravel bars are underwater.

 

[Capt1972]

You can't see it in the last pic. It's hidden by the rubber skirting around the jet pump. The exhaust outlet is between the jet pump and the 'box' that it is bolted into. The tube near the steering nozzle is what would normally be the 'enema' on a PWC. Instead, I have it hooked to a quick connect fitting, with a coil hose and spray nozzle. This way, I can hose down the deck of my boat, as long as I'm underway, so there's enough pressure at the nozzle.

View attachment 1


In the other pics showing the engine, notice the large black hose that goes into the top of the jet tunnel, near the transom.


This is where the exhaust enters the box. The rubber skirting around the jet pump contains nearly all of the sound coming from the exhaust, and because it's exiting near the jet unit, a lot of the sound is also muffled by the aerated water exiting the jet pump.

So the exhaust is "injected" after the impeller?

 

[PSG-1]

You can't see it in the last pic. It's hidden by the rubber skirting around the jet pump. The exhaust outlet is between the jet pump and the 'box' that it is bolted into. The tube near the steering nozzle is what would normally be the 'enema' on a PWC. Instead, I have it hooked to a quick connect fitting, with a coil hose and spray nozzle. This way, I can hose down the deck of my boat, as long as I'm underway, so there's enough pressure at the nozzle.

View attachment 2


In the other pics showing the engine, notice the large black hose that goes into the top of the jet tunnel, near the transom.

View attachment 1
This is where the exhaust enters the box. The rubber skirting around the jet pump contains nearly all of the sound coming from the exhaust, and because it's exiting near the jet unit, a lot of the sound is also muffled by the aerated water exiting the jet pump.

So the exhaust is "injected" after the impeller?

Hopefully this image will serve as a visual reference:




Part #46 and #47...that's the baffle system for a Yamaha VX110, and this is basically what I copied from for my design.

The exhaust is contained within the space formed by the tunnel (basically a large box made from 1/4 aluminum plate) that the jet pump bolts up into. There's about 2 inches of clearance between the exhaust flange and the stator assembly of the pump. At no point does it actually go through the jet pump. The rubber skirting is notched to fit around the pump, and it's basically about where the exit nozzle bolts to the back end of the stator vane assembly.

So, basically what happens is that the exhaust passes through the flange on the top side of the box, and then the sound gets trapped inside of that, with the flexible rubber skirting allowing the sound to pass through along the edges of the pump, and along the bottom edge where the ride plate is. While it's not directly being injected into the aerated water from the exit nozzle, the sound is exiting close enough to this that the sound is diminished a good deal by the water exiting the pump, as opposed to having the exhaust routed like a typical PWC, where it's just a hole right out the back of the boat, that allows all the sound to escape with no baffling.

 

[PSG-1]

Yet another overhaul of the Aluma-Jet.




This time, I'm working on the hull. When I first painted the bottom with Rust-O-Leum roll-on truck bed liner, I had sandblasted the bottom with Starolite. But I failed to etch with ospho, nor did I apply some zinc chromate primer. As a result, there were spots in the paint that had begun to flake and chip. And other areas where I had worn the paint off, from sliding over sandbars. In the areas where the paint was flaking, I noticed 'sugar' starting to form. Not good.

So, after 10 years, I decided it's time to re-paint the bottom. But not just with any paint. I'm going with Line-X type XS-350, which is military grade, and much more durable than what they put in the truck beds.

However, because of the horrible condition of the existing paint, the guy at Line-X said the bottom needs to be cleaned off, and I fully agree.

At first I tried a wire wheel. Very slow going, and I couldn't imagine having to work upside down on the entire boat like this. Tried a flap wheel, and it loaded up, started smoking. No good. So then I decided to use aircraft coating remover. It works, but just barely. Mixing some laquer thinner with it does help break down the epoxy of the bedliner coating. 2300 PSI power washer, with a turbo nozzle does as well as I could do with a scraper, especially with my screwed up shoulders.

I'm about 99% done, but now we've got a storm system that's going to dump rain for the next 4 days, so, it's at a standstill.
Once I get the paint off, I will go back and etch with ospho, then power wash, and have it line-x'ed.

Will post more as it progresses.

 

[PSG-1]

After 6 gallons of stripper and a week of blistering the old paint and power washing it, I've finally gotten down to bare metal.







Tomorrow morning I'm taking the boat to have it coated with Line-X.