Another Jet Ski John Boat (New pics and video 01-18-2012)

[PSG-1]

Haven't messed with the interior much this past week. I did order and install a new impeller and I'm very pleased with it. I went with a Skat-Track Swirl in the 14-22.5. This replaced the OEM Seadoo 15-23 impeller. I chose to replace the impeller for a couple reasons. First, the stock impeller was a little under the spec for clearance with the pump wall. Secondly, I researched fairly heavily and the skat-track swirl was highly regarded for hookup in rough water. It has a curved leading edge that helps eliminate cavitation in aerated water.

Got it installed this afternoon and headed to the lake with my co-captain to give it a run. Cavitation is much less with this prop. All but gone until you get full throttle in the small chop that was on the lake today. Will run 45 mph all day long. Hooks up great and has a lot more bite than the stock impeller. I'm extremely happy with how worked and hope to have a few chances to work on the interior over the holidays.

https://youtu.be/soY6GbQIbDo

Video work is far from my specialty, and I can't get my co-captain to do anything but enjoy the ride from the front. The boat is much more consistently fast with this impeller. Bow rise is next to nill. Had a chance to run it in some pretty skinny water this afternoon and as it sits now it will float in 4.5" and get up on plane in 10".

Another advantage to swirl impellers is that they are less prone to fouling than a straight-edged impeller. because the leading edge is curved, weeds and other debris tend to slide off the radius, then they are chopped between the wear ring and the impeller....where, with a straight-edge impeller, they tend to stay caught on that straight edge, if that makes sense. Also, as you've already noted, swirl impellers are better at staying hooked up in rough water.

 

[Ride_Klein]

PSG-

Glad to know that. It makes a lot of sense that they'd be less prone to fouling. Hopefully I'll run this thing in the swamp soon and find out just how hard I can work it.

RK

 

[PSG-1]

From my own experience in the swamp, you might not foul a prop, but you are likely to foul your intake grate. If you have a stomp grate, it's not a problem. But without a stomp grate, it can be a real PITA to un-foul a grate.

Also, when operating in areas of silt or debris laden water, keep a close eye on your cooling indicator streams, you have to be careful about the cooling flow being blocked and running the engine hot.

 

[Ride_Klein]

More bad blackberry pictures to share tonight. Got some work done on the floor. I have a brand new respect for all of you pop riveters out there after installing close to 100 tonight. A friend of mine donated some discarded aluminum road signs and I'm using them for the floor. It is still a work in progress, but I think it should work well. I built a frame off the existing stringers using 1.5" aluminum angle.


Cut the signs to fit, and then riveted aluminum angle along the topside of the floor along the gunwales.


I put the angle on top to support the floor and provide an anchoring place for the plywood finish panels that will run down the side. When I solve the foam puzzle under the floor I'll rivet it all down to the frame I build underneath it. The space between the rear deck and the floor is where my seating bench will go. This will provide some more storage and cover up the fuel tank on the port side of the boat.

Snapped a picture of the battery I relocated to the bow. I was having problems with cavitation and thought I needed some more weight in the bow. Not sure it helped with the cavitation because I added the prop at the same time, but it really cut down on the bowrise upon acceleration. That was good enough for me so it is there to stay. I used 4 ga wire to cut down on any loss I might have with a long run.


Also snapped a picture of the rear deck and rear deck support that I finished last week. The rear deck support is made out of 1.5" aluminum angle. The deck has a single lid in the front, and then a smaller hatch that allows access to the splash well that I covered. I wasn't sure about the single lid, but after living with it I think it is going to work. The flat storage in the old splash well is going to be really nice.



From here I need to complete the side finish panels, build the front deck, clean up the engine wiring harness, build the seating bench, bilge pumps, lights, and then paint.

 

[Ride_Klein]

PSG-

I have a raw water strainer headed my way to help alleviate silt and debris ingestion into the cooling system. I also have the "pisser" tube off of the exhaust manifold plumbed out the starboard side right next to the driver's seat to help keep an eye on how things are flowing.

 

[PSG-1]

Yes, a water strainer is a very good idea. It's much easier to clean a screen than to try unclogging the cooling passages of an engine.

One other thing I would suggest would be to buy an outboard motor water pressure gauge, and mount that in your console. A pitot tube, similar to a speedometer tube, is connected to the back of the gauge. Get a "T" fitting, and plumb it in AFTER the water strainer in the cooling loop, and connect the pitot tube. Don't put the T fitting before the strainer, because you will continue to get a pressure reading even if the strainer is completely clogged.

Once you have your gauge properly installed, you no longer need to take your eyes off the water to look for indicator streams, etc. You simply glance at the water pressure gauge to know that your engine is getting water. If the strainer clogs, you will instantly see a drop in water pressure.

To me, this makes a lot more sense than a temp gauge, as with a temp gauge, by the time you realize something is wrong, the engine has already run hot.

With the pressure gauge, you instantly detect a drop in pressure, shut down the engine BEFORE it ever has a chance to run hot, not after, then, clear the obstruction, and you're good to go.

This is the setup I'm running with my jetboat, and it works exactly like I described. Typical water pressure readings are about 6-7 PSI at about 6K RPM, and at WOT, it approaches the 15 PSI mark. Your results may vary. This is one of the best ideas I've implemented on my boat, I should have done it a long time ago.

In fact, I think it's such a good idea, I went ahead and bought one to install on my other boat, so I don't have to look back at my outboard to see if it's peeing, I can glance at a gauge and know if there's a problem. just got it yesterday, I'll be installing it sometime today.

 

[Ride_Klein]

Couple pics after spending way too much time scratching my head in the garage. I finally solved the foam puzzle and got 95% of it back under the floors. I'm going to pick up a few more blocks to add some on both sides under the rear deck and the balance of what I have left will go in the bow in front of the battery. Once I got the foam solved I was able to install the floors for good and work on the trim panels and seating.




View from the Stern


The rear deck is 55" wide and 45" long. I'll add a couple tie downs for decoy bags so we can keep them out of the floor.

The seating bench hides the fuel tank, and will be hinged to have storage underneath.

The space in the Trim panels will hold rods or shotguns depending on the season.

The floor area is almost 6 feet long and will be mostly open except for a cooler that will double as a step onto the front deck.

Haven't started the front deck, but that's next. It will be 4' long. Should have 2 great fishing areas between the two decks. None of the plywood panels are installed permanently. They all need to be pulled for filler and paint.

Thanks for letting me share.

 

[Ride_Klein]

PSG-

Nice to have a gauge so it's easy to see at a glance. I'll definitely add it too the list.

 

[PSG-1]

Yes, the pressure gauge is definitely a nice addition. Got mine installed in my Triton the other day, tested it out on the water yesterday. It works as expected. No more looking back at the motor to see if it's peeing.

Some of the places I run, taking your eyes off the 'road' in front of you can be hazardous. Inattention to the task at hand for even a second can result in running aground. So, I feel better about it already.

Your boat is looking good. Kinda the reverse of the approach I took with my build. I did all the structural work first, then did the engine.

But, that method of approach can cause issues. If you look back at the photos of my build, you can see that before the rear engine cowling was painted, it was flush with the rear deck area. Then when I went to install the engine, I realized it wasn't tall enough, so, I had to raise the cowling by another inch or so......d-oh! #-o LOL

I'm also convinced that using diamondplate, like I did, is a waste of money. Using smooth aluminum like you are doing is a far better method. Diamondplate looks nice, but as soon as the points lose their edges, or as soon as you paint it, that stuff becomes extremely slick, especially when wet. Then if you try to put a non-skid additive on top of diamondplate, it really looks crappy. So, you're taking the right approach with the smooth aluminum, for sure.

And as far as obtaining more flotation foam, I had an idea. What about the blocks of flotation foam like they use on floating docks? That stuff is designed to be in constant contact with water, not to mention having a tremendous amount of buoyancy to be able to keep a wooden dock afloat. I would think that would be the ultimate solution. Just a thought.

 

[Ride_Klein]

I kind of lucked into this smooth aluminum and it was impossible to turn down. All the painted surfaces will get a traction enhancer to help make footing a little better.

Dock foam was the route I was going to go with, but a friend of mine is pulling some flotation foam from the seats in his old flat bottom boat. If he can get it out in big enough pieces I'm going to "recycle" it for him in my boat.

PSG- If you get a chance could you snap a picture of the bilge pump you're using for your deck area. I Like the idea of keeping the deck and engine compartment separate, but I'm hitting a wall on the execution and placement of the pump.

 

[PSG-1]

Ride Klein,

The way I have my bilge system, I have the engine compartment sealed off completely from the main deck, with a bulkhead. At the engine, the bulkhead doesn't come all the way up, though, because of the head pipe on the front of the engine sticking out. The bulkhead is about 10 inches high at this point. But, the cowling fits over this, so, that seals it the rest of the way. With the cowling removed, the water on the main deck would have to exceed 10 inches in depth to flow over that bulkhead and into the engine compartment.

At the rear center of the main deck, I installed a round deck plate style hatch. Then, I used one of the fully automated 500 GPH bilge pumps. I drilled a hole through the rib between the main deck and the engine compartment, and routed the 3/4" hose to the bilge pump through that. This hose runs between the hull of the boat, and the false bottom of the main deck, where it's connected to the bilge pump. Yes, it's a very tight fit, and a trick to route the hose like this, but it works like a charm.

I will get a few pics of it today, so you can see exactly what I'm talking about.

 

[PSG-1]

OK, here's a few shots of the bilge system I have in my boat:

This one shows the engine cowling in place, along with the cover to the bilge pump. The cover allows water to flow into the sump, but the screen stops leaves and trash from getting in there.


This is the bilge pump:



This one shows the cowling removed, with the internal bulkhead I mentioned.

My original intent was to have the bulkhead go all the way up, but even with the engine set back as far as possible, it was about an inch too long, and so, unless I wanted to re-design a lot of the deck, I had to do it like this.

So, basically, where you see the diamondplate end, that is a rib. This entire rib was sealed with 5200, before the diamondplate was placed on top. The hose runs from the bilge pump between the diamondplate upper deck, and the actual hull of the boat. A hole is drilled through the rib, with the hose routed through it, going back to a thru-hull fitting at the transom.

So, with it set up like this, as I said, the water has to be 10 inches deep before it would ever go across that bulkhead, and that's if the cowling is removed. The cowling overlaps, and has gasketing, so, that seals it the rest of the way. Any water that gets on the deck, has to go into the sump, it cannot pass into the engine compartment, because, as I said, that rib is sealed. Once it hits the sump, the bilge pump takes care of it.

And then in the engine compartment, I have another 1100 GPH bilge pump with a float switch, mounted on the right side of the jet tunnel, as well as a pressure-fed bilge that's hooked to the jet pump, mounted on the left side of the jet tunnel.

Basically, I can dump about 25-30 gallons a minute with the 3 bilge pumps on board.

Hopefully the next time the so-called 'captain' aboard the 'Eagle One' Parasailing boat swamps my boat, I won't have $3K in engine damage like the last time around.

 

[Ride_Klein]

Thanks for the pic PSG. I like the idea of a sump for the cockpit. The picture helps clear it up.

 

[Ride_Klein]

Wheeeewwwwwww. 95% of the way there. Rough interior is in, primed, and base paint. This boat will end up camo, but I haven't decided on what pattern to use. Grey it is for now.

That's an old seat that came with the boat, but couldn't resist mounting it for this weekends lake trip.

Bow area with anchor storage up front and large item storage closest to the cockpit.

The thin panel between the deck and the gunwales was a PITA. I'm sure this will be changed in the future, but there are ducks to chase this year and January is the time to do it here in North Texas.

Stern deck and bench seat.

Engine hatch is a single piece. Engine in the center, fuel on the port side, and then storage on the starboard side. The bench seat has storage beneath. It hinges forward and houses the battery. I moved the battery back to this area after talking with a couple jet guys. Hoping to keep the "window" of the jet inlet open a little longer by not being so bow heavy. We'll see if this helps cavitation or not. I left the battery extensions up to the bow so I can move things around pretty easily.

Really appreciate everybody's help, comments, views, and interest. Nice to be able to share and learn.

 

[fool4fish1226]

Looks like you made some pretty good progress. Let us know how it preforms with the added weight.

 

[PSG-1]

Thanks for the pic PSG. I like the idea of a sump for the cockpit. The picture helps clear it up.

Yeah, it was harder to explain than the picture shows. :mrgreen:

Anyhow, your boat is looking good! Keep us posted.

 

[Ride_Klein]

It was a great weekend on the water. Had fun with the boat, chased some birds, and broke the boat. All in all a great shakedown run. The engine struggled at first. Acted like it wasn't getting enough fuel. I believe the fuel selector valve is faulty and once we found the sweet spot on it the boat ran well. The added weight of the deck/floor/panels/etc. Didn't appear to affect the top speed much at all. Still getting between 45 and 50 on the gps depending on water conditions. Moving the battery back beneath the rear bench seat worked well. No real cavitation to speak of. The combination of the weight balance and new prop have helped solve that issue. I'm very happy with the new prop and would recommend it to anybody having cavitation problems with their jet john project.

A quick overhead look before we hit the water.


Rear view of the decks and floor area.


Closeup view of the paint texture.

I used Behr porch paint from Home Depot, and then added the "Floor Finish Additive". This boat will get beat up pretty good during duck seasons and repainting is a fairly regular occurrence. We've had good luck with this stuff in the past on other duck boats. It seems to do better than other big box store paints and on par with more expensive marine based ones.

Front Storage Compartment

I know storage on a boat always fills up fast, but this one seems to be stuffed to the gills.

Finally a little video

https://youtu.be/svjyZXZsLgo

Broke the port side motor mount sometime during this session of messing around. Glad it happened close to the boat ramp instead of early one morning with a storm approaching. Should be an easy fix. Still have some final touches to put on the interior, but those will come with time.

 

[PSG-1]

I cannot think of a better way to kick off the new year! Outstanding job. Really looks good.

 

[wyatts dad]

Really cool project, from the read it sounds like it went well and was actually a fun project, that is very cool. I just applied the two part foam myself this summer, I know it is late to passs this on, but in my research and consulting with the Jamestown distributors, it turns out the reason for the soggy foam we all find is that it is not installed with the boat owners best interest in mind. JD told me that it must be allowed to breath, it must be allowed to vent and allow the moisture to evaporate, or else you will get soggy foam, granted it will take a while. Fourtunately I found out in time to make those sections removeable and hopefully prevent this. The way it was put to me was that if you get a good drencing, open it up.

 

[PSG-1]

Regarding flotation foam, even if you're not swamped or drenched, water still gets in the foam, through condensation, and other small amounts of water. It's a good idea to occasionally open up all the hatches during some dry weather, put the boat in the sun, and let all the moisture cook out of it.