New to PWC with a interesting prroject.

[OCD Solutions]

There are many reasons to take on a project and while unconventional, I think you have started something great here. You have earned my respect and my support!

I'd like to offer to send you anything needed electrical wise when you get to that point but I'm also kinda curious to see what you come up with on your own.

 

[Scott Bennett]

Thanks OCD, I'll keep up with pics as we go. My family back in TX is very curious as to how this will work. I'm always building something keeping them entertained.
This is project was started as a MWR for the guys. It is fun to see how far we can go with what we have. I think we are a bit stalled out on the construction side until we get the 5200 adhesive. The mail takes 3-6 weeks for us. So that gives me time to prep and clean all the surfaces. I also will cut all the framing for the ski and runners inside of the boat.
If we get the 5200 next week it will be in the water for a float and power test in two to three weeks, fingers crossed.
Right now it is 114 degrees outside with 70% humidity. Last night when I finished the rough cuts it was 102 at 2300hrs just crazy hot. I actually started this thread because I really dont know much about boats or PWC.
We've been doing searches on converting from a single cooling system to a dual as I think the engine will get hotter from the added load. The diagrams I thought I found gets stripped to just the source code. If anyone has a cooling diagram please post. We will need to omit the buildge and use an electric in its place. Also for dual cooling I want to re locate dual pissers up on top so it will be easy to keep an eye on them, do I need to reduce the ID so it will retain back pressure?
The intake spot on the bottom will get a transition area that lends well to low pressure for the pump hopefully aiding the water supply maybe lowering the stress of the engine.

 

[Scott Bennett]

Not a PWC I know. This was my last deployed project that kept me entertained.

 

[Scott Bennett]

I've been at a stand still waiting for the 3M 5200 to arrive in the mail.
Everything takes 3-5 weeks to arrive. I now have the FX1 hull all positioned correctly and shimmed. I have cut a frame out of 2x4 to "lock" it into the transom. Once the 5200 arrives I will remove everything and bond it all up.
That's when the fun starts. I will glass the entire rear section together. I have already glassed all the holes in the boat so its a fresh start. We got the gear drive steering system ready to mount, I hope to have that in and working by the weekend.
I will extend all the started and kill switch wires to the drivers spot. The throttle might be a little bit of a trick but I have an idea to use some left over disc brake control cable from my bike to extend it and use the thumb throttle incorporated onto a grab pole since they are both 7/8". We are still looking at a first test in 2 week ends. The results of that test will determine the direction we go. We have been looking at some of the old 16 foot 1950s boats that use the 35-50hp motors and they went plenty fast for what we are going to use it for. If we hit 80% of those perceived speed we will be happy as a clam.

 

[OutRAGEous]

This looks like a cool project and I admire your ambition and perseverance! I wish you good luck getting your craft running, and I'm sure you'll be thrilled once you're on the water.

Be careful comparing a propeller driven boat to a jetboat...the two drive systems are very, very different. Especially different when you're comparing low speed thrust between a jet and an a prop. It's possible that your boat will struggle to get up on to plane, especially considering that small pump from the FX1. You'll need to be able to get a lot of weight forward in the boat to avoid the stern squatting in the water. Trim tabs on the boat hull may help you. For high speed comparisons, you would typically factor the jet boat power down by 30% when comparing to a propeller boat. (ie 50hp jet drive is comparable to a 35hp propeller boat, roughly). This is not applicable for lowspeed operation though.

Regarding the cooling of the engine, you may not need to go to a dual line cooling system going. What is the water temperature where you are? Probably similar to lakes in Arizona/Texas I'm guessing. The load on your engine doesn't vary the same way that a propeller engine (outboard) will. The jet will pump a similar amount of water with a similar load on the engine no matter the boat speed or the load in the boat. The speed of the boat changes the pressure in the jet pump slightly, but your boat may not reach speeds that change the load on the engine much at all. The load on the engine is primarily dictated by the pitch of the impeller and the design of the jet pump.

Your jet pump will be more efficient if you cut some of the bars out of the intake grate. The fewer bars the cleaner the water flow to the pump will be.

 

[BostonSJ]

That poor FX1

I literally said the same thing..out loud.

 

[Scott Bennett]

Thanks for the info OutRAGEous.
I don't know much about boats. This is why I started this thread. I'll look into the trim tabs. I was looking at glassing in some flaps from the side of the FX1 to the back of the boat to give it some surface area just so it wouldn't dig too deep and stay there. I have to research some angles and run them through my physics simulator. I can base everything on 20-30 knots. Much more than that and it will require adjustibility. I don't know if that is something we can do with what we have here.
Again for those saying poor FX1 maybe your right we should have left it in the scrap yard to be shredded. Or maybe its just out of ignorance. Maybe if you had the chance to visit a real 3rd world country and see the limited resources that you have to work with. If it was a couch style jet ski I would have kept that for MWR. A stand up FX1 has a bit of a learning curve and lot more possibility of my guys getting hurt than a nice slow tame boat. Everything has a purpose and reason behind it out here. Carelessness will get you in serious trouble here. These posts are only here for productive advice for my lack of boating knowledge not for snide comments about a junked FX1 or even the junked boat. Please don't bother posting those. I've seen this type of posting over at viperalley vs the real racers on viperclub.org. I prefer constructive info.
Off my soap box and on to a next question.
Were not too interested in from the dig takeoff. Would going into a 760cc jugs and head allow a little bit more RPM.We could make up a little cruising speed from a bit more RPM correct? Would a larger 144 pump assist? I'd think the larger pump would only give it more acceleration. I'm looking at going into the 62T case as the reed design is a bit more efficient than the 61X, I've already got the twin 38s.

 

[OutRAGEous]

Scott,

I'm a relative noob to PWCs too, but I've spent the last 35+ years on the water for fun and for work. I've operated all sorts of prop-driven runabouts, two 28' prop-driven water taxis, cruisers up to 60', a 30' twin engine jet powered work boat, and a few sit-down jetskis. My newest project is a 1992 Boston Whaler Rage which came from the factory with a Yamaha 650 and 144mm pump. The Whaler is 13.5' and is supposed to weigh around 850lbs. It has a very flat bottom. My jet experience comes from the workboat I ran, sitdown PWCs, and my Rage.

I just repowered my Rage with a 61x and a brand new Solas 144mm pump with an Impros Hooker impeller. The upgrades have made a huge improvement in handling of the boat because the pump stays hooked up. The motor swap from the 650 to the 701 was necessary mostly to turn the Hooker impeller. With just me aboard, the boat went from 26.5knots with the old drive to 30knots with the new drive. Low speed handling is indistinguishable.

I'm sharing this info with you in an effort to give you a reference point for your project. From my experience and understanding, the low speed operation of a jet is mostly due to the amount of water you can move...more obviously being better. This isn't so much a question of turning the impeller faster but more a matter of the pump size and the interaction with the jet stream and the stationary water behind the boat. In this regard your FX1 pump is very undersized.

I have just fitted a trim nozzle to my boat and hope to get it operational this weekend. My goal is to trim down to assist the boat getting "out of the hole" (aka up on plane). Right now if two people are on the rear bench seat (captain and passenger) the boat struggles to get on plane, even with full throttle. Looking at your pics, I think that 30knots is unlikely to be achieved. If your boat can get on plane, I suspect you'll be closer to 20-25knots. If you can't get on plane you'll be stuck in the water doing 7knots. With a jet there isn't much in between. Personally I would create some fixed trim tabs for initial sea trials and just get the boat out on the water and experiment.

I know that parts/supplies are difficult where you are. I have lived and worked in the high Canadian Arctic and have seen firsthand the improvisation and ingenuity of the residents. Down in civilization people would scoff at what's up north, but the residents up there have no other options and don't care what the "southerners" think. I imagine you're in a similar situation. I hope this info is useful to you and I wish you success with your project.

 

[Scott Bennett]

I have been checking out the Bennett's SLT10. I see them all over for $140ish. That wouldn't get too far out of the budget. Does anyone have any experience with these.
Electrics and hydros are out of the question because of cost and support system that will be lacking in our boat. I understand now how they work and the whole up on plane thing.
I will know more in 10 days. I just got the 3m 5200 in today along with a gal of 2:1 epoxy. Tonight after work we will 5200 the crap out of the just ski hull, frame up the rear cut out and run about 4 carriage bolts up from the bottom to extra secure the two hulls together. Saturday all the fiberglass work will be laid out, Sunday smooth out the glass and let everything harden up for the week while I complete the steering reverse horn and rig up the throttle, start switch and kill switch w/ lanyard. The 11th will be a test to see if we have created something that will do the job or if we should construct more mods.
The real work will start if it proves to be successful. Lots of sanding and painting along with complete interior from scratch. A 100% new trailer will need to be built from scratch as well. I have been collecting metal for this and got plenty of 6311 electrodes.

 

[nucleus_coolins]

Fun project! Must be painful wrenching in those temps, especially with lack of supplies. Post up some more pics when u get it all glassed and go for a water test

 

[Scott Bennett]

I do love building projects but the crazy heat with high humidity take a bit of the fun out of it.
That being said, If I can get the boat done and tested in the next month and a half we might be able to make the group of boats that go out and dive with the whale sharks.
This weekend we got a lot completed. The steering is done. I 3d printed a 2:1 bell crank because the rack and pinion steering was too slow. This also reversed it to a push pull config.
The boat was pulled off the trailer and flipped and fiberglass laid into the cut area. Once the glass is cured we will apply some Aquaguard boat bottom paint so it will be ready to go into the water on Sunday.

 

[Scott Bennett]

I do have one major issue. The scraper portion of the bump is cracked but not in the inside it looks like just the housing. How long will this last just for testing? I dont want to mess anything up but need to get it tested to asses what happens next.
I'll look for one tonight but it will be 3-5 weeks before we see it.

 

[Scott Bennett]

 

[Scott Bennett]

As I mentioned the wear ring housing being cracked, I see a past post for using the Kawi 650 pump. The issue will be getting everything milled and pressed. I have yet to learn about a machine shop here.
Example, I bought a 1996 Suzuki escudo (sidekick). It was cheaper to order new wheels and tires from Summit racing to replace one wheel that was rusted up and 4 15" tires locally. The new wheels needed larger hub area for the front. I took them to a guy who said he could do it. I later found out he was just out there grinding them out with hand tools to the sharpie line I drew. That is the Djibouti machine shop I guess.

 

[MADMAT]

Wow man.....crazy place! The project is moving along nicely though! Rip it!

 

[Scott Bennett]

We got the first coat of boat bottom paint. This thing is already looking better!
I got two quarts of AquaGuard water based, 20% copper, high solids paint. It took 15 min of stirring just to get it to be able to apply. This stuff has the consistency of lumpy sheetrock mud.
What should take no more than 20 min to paint took over an hour. Crazy stuff.

 

[BigV]

Great project! And I understand your objective completely. Who cares what pump or prop it has. If it goes two mph that will still get you out fishing! Keep it up

 

[Scott Bennett]

I agree. If it gets us there and back its good. However some of the guys agreed to pitch in and go for a fresh 760 and the mod of a 6R7 with 61X forcing cone to get the 144 pump. After it took 7 of us to flip it that was an easy proposal.
The funny part is now that it looks better they are even more in to the project. It was pretty sketchy looking fresh from the scrap yard. We couldn't really find any holes or large patches to speak of. I took care of the second coat of bottom paint tonight after work. Easiest task yet. After rolling and brushing I'm glad my mom sent me two Harbor Freight airless sprayers to do the top and inside.

 

[Scott Bennett]

anyone have a 6R7 pump sitting around?

 

[Quinc]

If I had anything you needed I would give it to you. Maybe @Rdrttoy @JetManiac has something.

Maybe mill the head the a little on the 760 and get some @yamanube porting templates to get a little more power out of it. Assuming you can get 91+ octane?