a new jet ski jet boat project

[scubapro820]

I was pointed to this forum after being a member at iboats I hope to get help with an already well underway project but I will fill in more details when I'm sitting at a desktop , but the projects a blue star 14 v hull custom topper and a 1997 tigershark 1000 motor 1998 Yamaha hp 800 pump . I've read many posts about the tigershark brand but I've been building and using the same Suzuki motors for years as an arctic cat tech and with proper maintenance they last a very long time and I like them anyway I'm working on mounting the engine then onto steering . Any how thanks in advance to all those who share their experiences I'm excited to be here !

 

[scubapro820]

Ok now Im on my desktop, so I used 1/8'' aluminum to build an adapter plate to the rear of the boat. I still have to make the support for the pump in the rear. When I get my coupler in the mail I have to mount the engine. Im thinking about using 1/8'' or 1/16th'' aluminum 2x4 or 1x3 tubing to make a cradle type mount for the engine. I had some success using 5356 wire and a push mig setup the cabin on my boat was based on the coast guard design works pretty well for long river trips in minnesota. I use the boat to get to remote areas around the mississippi for hiking hunting and camping trips.

as for steering there is a push pull setup from teleflex for jet boats that im looking at, does anybody know if the steering wheel and bezel that are teleflex are standard and can be reused. and another thing the jet nozzel looks like it moves 4.25 inches. the kit from teleflex moves 3.5 . I really do want to use a steering wheel for control so I need some help/ ideas here

 

[PSG-1]

Ok now Im on my desktop, so I used 1/8'' aluminum to build an adapter plate to the rear of the boat. I still have to make the support for the pump in the rear. When I get my coupler in the mail I have to mount the engine. Im thinking about using 1/8'' or 1/16th'' aluminum 2x4 or 1x3 tubing to make a cradle type mount for the engine.

Right. A rail design, where you run the tubing longitudinally, under each side of the engine, for the motor mounts to bolt into. You really should use 3/16" or even 1/4" wall thickness for the tubing, though. 1/8" is not going to be beefy enough, and 1/16" definitely won't be strong enough either. You also need enough material thickness to put the motor mounting bolts into. I believe the rule of thumb is to have thread engagement that is 3X the diameter of any given fastener.

So, if you're using 1/4" fasteners, your material thickness really should be 3/4" But I think as long as you use some 3/8" flat stock, welded to the top side of the tubing, at each point for the motor mount, then drill and tap through the flat stock as well as into the top of your tube, that gives you about 5/8" of thread engagement, which should be adequate.

I had some success using 5356 wire and a push mig setup the cabin on my boat was based on the coast guard design works pretty well for long river trips in minnesota. I use the boat to get to remote areas around the mississippi for hiking hunting and camping trips.

5356 wire is what you should be using for any aluminum that will be used in water, particularly in salt water. 4043 is not as corrosion-resistant as 5356. Also, the 5356 is a much harder wire, which is a good thing if you're using a conventional MIG, instead of a spoolgun. Trying to run the softer 4043 alloy wire through a regular MIG is just asking for a PITA, even if you try using a teflon liner, it's going to bird-nest at the drive rolls.

as for steering there is a push pull setup from teleflex for jet boats that im looking at, does anybody know if the steering wheel and bezel that are teleflex are standard and can be reused. and another thing the jet nozzel looks like it moves 4.25 inches. the kit from teleflex moves 3.5 . I really do want to use a steering wheel for control so I need some help/ ideas here

OK, Teleflex makes 2 different helm controls for jet boats. One is configured to be 135 degrees from lock-to-lock. The other is configured for 270 degrees from lock-to-lock. I used the 270 degree on my boat.








The cable you need to use is a Teleflex CC694 series (I think they've changed that to CC6400 recently) Anyhow, this cable has 4 inches of travel, and it uses 5/16" x24 threaded ends, much heavier duty than the CC633 series cable, which uses 10-32 threaded ends.

The CC6400 cable has one end with bulkhead nuts and washers. So, for this end, you just need to make sure that you position the cable where the full travel coincides with the full travel of the steering nozzle. Depending on the set-back of your pump, you may either have to in-set the bulkhead, or move it out, to make the setup work correctly.

This sounds complicated, but basically all it involves is using a short length of round aluminum tubing with an end cap welded into one end, with a hole through the center for the cable to pass through. The tubing ID needs to be large enough to accommodate the cable, with the washers and nuts installed, and it needs to be a little bigger, to allow for a deep well socket to fit in there to tighten the nut (a modified 7/8" oxygen sensor socket works great for this)





Even if you don't have to inset the cable, this socket still works great for cable removal. Basically, modify the O2 sensor by cutting it off close to the end, then splice in a 6" length of pipe of equal diameter.





Anyhow, back to the bulkhead adapter pipe. Use a hole saw and cut a hole through the transom for the aluminum pipe to fit into. Then, with the cable installed into the pipe, and the pipe going through the hull, you install the ball end fitting on the cable and connect the cable to your steering nozzle. Checking full left travel (cable travel extended) then full right travel (cable travel retracted) you move the bulkhead adapter pipe in, or out, as necessary, then tack it in place. Remove the cable from the adapter tubing, and weld the tubing into the transom. (I used square tube for mine....would have been a helluva lot easier with round tubing now that I think about it.)

Here's a few pics to illustrate what I'm trying to explain:


OK, in this one, you see that the cable is actually in-set into the hull, into the piece of square tube. This is a shot of the reverse gate cable. The steering cable is set up in a similar manner.


This is what it looks like from outside the boat:

A shot of the steering cable extension from the transom, with the ride plate removed:



It may be a little difficult to see these clearly, because everything is coated with black anti-fouling paint.




Now for the helm.....

The other end of the cable is a little different, but it can be made to work in conjunction with the Teleflex jetboat steering helm. There is a fitting that comes with this helm kit, you'll need to drill and tap into this fitting for some stainless set screws to act as keepers for the cable, to keep it from slipping back and forth. (Let me know when you get to this step, I'll walk you through it)




You can see in this closeup shot how the SS set screws hold the cable sleeve in place.

And just for a little added security, I secured the cable like this:



Yep, those are hose clamps, placed around the cable body. I have a set on the inside, and a set on the outside of the console where the cable passes through. I suppose a bracket could be fabricated with some set screws to secure the cable body, and this bracket could be bolted to the inside of the console. And at some point, I may end up doing that. But I've had no issues with this configuration, so, if it ain't broke, don't fix it.


Again, this is the setup I've been using in my jetboat for nearly 7 years, and it works great. I can spin the boat in its own length at 30 MPH, and I'm talking about a 16 ft DuraCraft johnboat, not a specialized jetboat hull. My steering nozzle travels about 1/8" from full lock in either direction, and the travel on the XL1200 nozzle is about the same as your pump, nearly 4.5 inches.

Anyhow, that's my input for right now. Like I said, when you start getting into doing the modifications, let me know if you have any trouble, I know every idiosyncrasy of doing one of these builds, as I've done it not once, but twice. I can definitely save you some time and difficulty.

 

[fender66]

Looks like a great project. I'm in to watching this progress.

And....Welcome to TinBoats! You've found the right place.

 

[scubapro820]

PSG-1 thanks for your input Im going to def have to get more info from ya and maybe some pics for the adapters and fasteners you used for your steering setup. Also is the cc before the number the length of the cable similarly to the last two digits on their other cables>? As for the engine mount Im going to use a nut on the backside of the aluminum tubing, and will def get thicker stuff to fab up with as I am still waiting on my coupler before I take measurements I dont know how much materiel I will need yet ! but when I do I will take plenty of pics.

 

[PSG-1]

PSG-1 thanks for your input Im going to def have to get more info from ya and maybe some pics for the adapters and fasteners you used for your steering setup.

I went outside and took a few pics of my setup, and edited the post to include those. Easier to show than to explain, for sure!

Also is the cc before the number the length of the cable similarly to the last two digits on their other cables>?

Right. If you were going to use an 18 foot cable, the number would read "CC64018" (that's for the 5/16x24 cable) or "CC63318" (that's for the 10-32 cable)

As for the engine mount Im going to use a nut on the backside of the aluminum tubing, and will def get thicker stuff to fab up with as I am still waiting on my coupler before I take measurements I dont know how much materiel I will need yet ! but when I do I will take plenty of pics.

It's a good idea, but how do you propose to get those nuts inside the tubing, or to get a wrench in there to hold them as you try to tighten the bolts from topside? :?: At least, this dilemma exists if you're using full-length rails. Now, if you're just going to use short sections of tube placed under each motor mount, it won't be an issue.

HOWEVER, if you're using short pieces of tube, instead of full length rails, you're not going to have nearly as much strength in the design, because there is less area that can be welded to secure the rails in place. You'll have to use some type of gussets, and they'll have to be tied into the structure of the boat. Either that, or you'll have to use cross-members that will tie the sections together. But they can't be too thick, or that will interfere with engine clearance underneath.

If you check out my build, I used a sheet of 1/4 plate in the engine compartment, welded to the framework of the boat, to have some good solid material to tie the rail mounts into. And I used full length rails.

When I installed the TS engine, I actually used carriage bolts, placed from the underside of the rails, then I welded the rails in place. But if one of those bolts had ever snapped, I would have been screwed,(no pun intended). :LOL2: I would have had no way to replace it, except for trying to cut all the welds holding the rail in place.

So, when I re-did the boat with the 4 stroke, I thought about this previous issue, and configured the rails differently, where the bolts simply thread into some really thick material. If you check out "Part 3" of my series "American jetboat High Output" you can see the rails I used for the 4 stroke, and how they differ from the rails used on the 2 stroke, which you can see on my thread "Aluma-Jet" or in my video "Aluma-jet Project"

Again, having done this twice, and with 2 totally different engine systems, I know most of the ins and outs and quirks that you're likely to encounter with doing such a project. Let me know if you hit any snags, I'll be glad to help out.

 

[scubapro820]

again thanks for yor help the pics and info will be very helpful

 

[PSG-1]

No problem. If you need any more info give me a holler at:

[email protected]


Good luck with it!

 

[scubapro820]

I found the cable series youre talking about , looks like tele updated the 6400 series to tel-ccx640xx for a part number but thats great , this is going to save me many headaches

 

[PSG-1]

Excellent.

Now, if you ran this idea past the techs at Teleflex, (using the 6400 series cable with the jetboat steering helm) they'd tell you that you need to use the jetboat steering cable. Well, again, the problem with that is that the jetboat steering cable only has 3 inches of travel. Put that on your boat, and it'll have the steering response of a **** barge. I know this because that's the type of cable I initially used on my boat. A waste of time, effort, and money. #-o

So, don't buy the cable/helm combination they offer. Buy the helm separately, then use the 6400 series cable. It'll require some modification and tweaking to make it work, as I explained earlier, but you'll find that when you get into building a custom boat, a lot of things have to be modified to make them work.

 

[scubapro820]

Ok so I got my coupler in the mail, babbits partshouse fresh cast from japan! I also picked up my alu 3x1x1/8'' tubing Im going to post a semi to scale sketch and some pics of the motor somewhat in place. the notches in the sketch are to allow the boats supports to remain intact I think its important for the boats rigidity

 

[PSG-1]

Ok so I got my coupler in the mail, babbits partshouse fresh cast from japan! I also picked up my alu 3x1x1/8'' tubing Im going to post a semi to scale sketch and some pics of the motor somewhat in place. the notches in the sketch are to allow the boats supports to remain intact I think its important for the boats rigidity

It took me a second to recognize the jet pump. Yours has the intermediate bearing housing, and the full-length drive shaft. Because of the available space in my boat, the drive shaft and the housing of my pump is cut very short, and there is no intermediate bearing, only the bronze bushing and the 2 seals where the shaft exits the intake duct housing. Of course, with the driveshaft of mine being so short, there's not much need for an intermediate bearing anyway, as the shaft has no deflection being that short. I wish mine had that bearing housing, but, it seems to work OK without one.

You'll need to fabricate some type of bracket to bolt the intermediate bearing housing in place.

The coupler you're using looks like a Kawasaki or Yamaha design....I'm guessing Yamaha. The rubber spider between the 2 halves of that coupler will eliminate all metal-to-metal wear, and it will allow for some deflection and vibration. However, it will not allow for mis-alignment. When you go to install your engine rails, you need to dial it in before you bolt it down.

To 'dial it in' you need a straight edge, and a feeler gauge. With the engine connected to the pump, lay the straight edge across the jaws of the coupler, and check for a gap between the straight edge and the coupler jaw with a feeler gauge around the circumference, like top dead center, then at 120 degrees, then at 240 degrees.

The maximum allowable gap (mis-alignment) is .020" Any more than this will cause premature wear of components like seals or bearings, or the pump shaft, and possibly even the crank shaft of the engine.

You may need to use shims on the motor mounts to get it precisely dialed in. Once you have it dialed in, then you secure the engine mounting system to your hull.

You're taking the right approach by installing the pump before the engine, its much easier to try to align the engine to the pump, than trying to align the pump to the engine.

 

[scubapro820]

I made my motor mounts last night, theyre just kinda resting and not bolted in yet or shimmed up but it'll go pretty well I think. btw I used a lincoln weldpack 3200hd with 5356 wire and 6061/63 alloy metals It takes a ton of pre heating with a map torch but once the whole piece is good and hot the welder had no problems no feed issues at all! and to think I was starting to think I hated aluminum.

 

[PSG-1]

It's looking better every time! Good rail design, too, it gives access to the bottom side, so you can install a lock nut, instead of having to use thick material to drill and tap for internal threads, which have the potential for stripping out.

When you first mentioned putting nuts on the back side of the tube, I didn't realize you were going to use 2 separate pieces of tube with a space in between them, I thought you were only using one piece of tube, between the hull and the motor mounts. That's why I was in a quandary about how you were going to put the nuts on the back side. The way you did the mounts is an excellent idea.

As far as welding, a little pre-heat is always a good thing with aluminum, as it assures better penetration on the welds, particularly where you begin a weld. Running aluminum wire through a conventional MIG can be a PITA, it will make you cuss like a sailor sometimes.... I did it for quite a while before I upgraded to a spoolgun.

The tricks I learned for running aluminum through a conventional MIG: use a teflon liner, keep the lead straight as possible, use a slightly oversize contact tip, minimal drive roll pressure, and hope for the best! (Keeping the gun at an oblique angle when starting a weld also helps, as the wire doesn't 'stab' the base metal, it hits at an angle and glances off, reducing the potential for a bird-nest at the drive rolls.)

I notice that you have the mount rails tied to the hull rails at 2 points. Since you said this tubing has an 1/8" wall, my only concern would be stress cracking of the welds being caused from engine and boat vibration.

If it were me, I'd go along the length of the inside of those 2 rails with a piece of 1/4" plate, cut for the width between the upper and lower rail, for the full length of the rails, to tie them together and eliminate any possibility for deflection, or stress cracking of the welds. Doesn't have to be a continuous seam, either. You can stitch weld, and stagger the stitch welds from the top side to the bottom side.

With the plate along the inside, this still gives you access to install the lock nuts on the bottom side of the mount rail, but as mentioned, it will give a tremendous amount of added rigidity to the rails.

My thought is that with the 2 rails only being tied together at 2 points, and being 1/8" wall, vibration could cause a weld to crack. And if one gives out, the next one is taking more stress, and it will be next in line.

It's important to remember that aluminum is only 1/3 the strength of steel, so, you have to account for that with any structure being designed with aluminum. As an example, look at the thickness of material used on an aluminum VS. a steel boat trailer.

Always better to be a little overkill with a design....especially with aluminum. It's better to have that added strength and not need it, than to need it, and not have it! You don't want your motor mounting system shearing loose and leaving you stranded.

But again, I like that rail design you've come up with. Being able to use bolts with lock nuts is a helluva lot better than tapping into a piece of aluminum and relying on threads to hold something in place. If/when I do another jetboat build, I've got the image of your design in the back of my head. Slightly modified, perhaps, but definitely utilizing the concept of being able to use thru-bolts with lock nuts on the back side.

 

[Ranchero50]

Scubapro820,

I hate to rain on your parade but I think you need to spend a considerable amount of time thinking about how your hull will react to the stresses of water and chop as it moves. As is you have absolutely no structure under the back of that hull. It's all going to flex bad, I doubt your coupler will last and I think it's really unsafe. The old thinhulls are what, .040" thick and have no ribs or stringers.

I don't see a 100hp inline jet working well unless you build a serious frame between the motor and hull.

That being said you have a pretty decent foundation. What I would suggest is figuring out some way to add ribs similiar to a newer hull, then run fore and aft stringers to tie the ribs together. The ribs are going to be a major PITA to fabricate and you'd probably be better off to buy a .080" 14' jon, then fit in your motor and pump with stringers supporting the ribs you cut. Actually with a 100hp engine I'd buy a 16' or even 18' hull and build it.

Check out my MV1448 build (in sig), I spent a huge amount of time thinking about the hull, tried to take some decent pictures and tell the story as I built it why I did things certain ways. I am very happy with it and there's only a couple things I would change if I redid it. There's some YouTube videos too.

PSG-1 and I have both been there and can help you get there safely.

Sincerely,
Jamie

 

[PSG-1]

Scubapro820,

I hate to rain on your parade but I think you need to spend a considerable amount of time thinking about how your hull will react to the stresses of water and chop as it moves. As is you have absolutely no structure under the back of that hull. It's all going to flex bad, I doubt your coupler will last and I think it's really unsafe. The old thinhulls are what, .040" thick and have no ribs or stringers.


I don't see a 100hp inline jet working well unless you build a serious frame between the motor and hull.

Ya know, I was so focused on the subject of the mounting rails, I didn't even consider hull flex as a factor, but you are absolutely right! There are no ribs or other structural components around the engine to make the hull more rigid. If the engine/driveline assembly cannot be made rigid, at the very least, vibration from the engine operating, and the weight of the engine slapping the hull in chop, fast turns, etc, is going to wear out thru-hull bearings, the coupler, or other components.

Worst case scenario, hull flex could lead to the base metal of the hull actually ripping apart, the engine mounts shearing loose from the hull, and the boat taking on massive amounts of water.

That being said you have a pretty decent foundation. What I would suggest is figuring out some way to add ribs similiar to a newer hull, then run fore and aft stringers to tie the ribs together. The ribs are going to be a major PITA to fabricate and you'd probably be better off to buy a .080" 14' jon, then fit in your motor and pump with stringers supporting the ribs you cut.

I don't think ribs would be too difficult to fabricate. Make them out of that same 1x3 tubing, make the angle cuts on either end for the vertical piece to go up against the gunwale, fit it together and weld it.

This might come as a surprise, but, there are no ribs under my engine in my Dura Craft. Granted, my hull is a little thicker, but still not thick enough to support the engine all by itself.
When I did that build, I used a sheet of 1/4" aluminum plate in the engine well, and where I cut the hole for the pump, I tied the gap between the hull and the 1/4" plate together with some flat aluminum stock, and welded all the way around. The 1/4" plate is also tied to the longitudinal stringers on the outside edges of the engine well, to the transom, and to the rib immediately in front of the engine well. Perhaps something like this would work.

I have photos of this on my "Aluma-Jet" thread, click the link on my signature for more details.

Actually with a 100hp engine I'd buy a 16' or even 18' hull and build it.

Check out my MV1448 build (in sig), I spent a huge amount of time thinking about the hull, tried to take some decent pictures and tell the story as I built it why I did things certain ways. I am very happy with it and there's only a couple things I would change if I redid it. There's some YouTube videos too.

PSG-1 and I have both been there and can help you get there safely.

You got that right. And like I've said before, I went through a lot of trial and error to figure out what worked and what didn't. I wish I would have had a resource like this board when I did that build, but back in 2005, I don't think the idea of jet ski johnboats was catching on like it is now.

But having worked through most of the idiosyncrasies on my own, I gained a lot of insight and knowledge, and I'm happy to share that with my fellow jetboat builders. I probably have a lot of other photos of my build that may not be shown on the board, so, if you need other photos, or info, give me a holler at:

PSG1Shooter@REMOVETHISgmail.com

 

[scubapro820]

Thi mod it to fit my hull is much thicker than the alumacraft .040 ere are 3 longitudinal stringers and 2 horizontal stringers 1 I am going to re install after I mod it my hull is much thicker than .040 its..091 or .080 the rear mount plate is 1/8 " and the most rigid part of the boat thanks for the concern guys but I also have put thought into its rigidity I do have more to be added to the hull later also. In Minnesota we have very smooth flat waters

 

[scubapro820]

* its .91mm

 

[PSG-1]

I think you mean .091" inches, not mm. That's about the thickness of the hull of my Dura Craft.

.091" is roughly 14 ga, as .062" is 16 ga, and .125" is 11 ga.

 

[scubapro820]

Ugh metric English or some such lol its heavier than an alumacraft whichever it is