Starting my first build with a jet TNT

About using jet ski motors to power small boats

Moderator: Bill Edmundson

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Mon Nov 21, 2016 7:27 pm

Hi Doug,
If I sounded a little too harsh in my last response I apologize. I've gained a lot of experience going down that road a few times and I guess I feel pretty strongly about trying to keep others from making the same mistakes I have.
I don't have much of a background with composite construction other than some basic knowledge and I was curious as to what about the polycore was a bad idea?
It looks like it would be a suitable material for a stressed-skin panel-type construction like a stitch and glue hull or like the sprint hulls? Or does it not have the rigidity and it needs a mold to maintain shape before the lamination process?
You've already gotten the first few steps going for you with this project:
1) you have a good idea of what you want to use the boat for.....
2) you've decided on a hull design that you feel would do the job and just as importantly, you like....
3) you have already done research to have a good idea of what materials you feel would allow the boat to do what you want.....
3) you've already made strides in obtaining suppliers for those materials....
.....am I right or no?

....at this point, the next step in my mind would be what powertrain you think would work well for your project. For running the rivers like you want, a jet would obviously be the best choice for the drive. The easiest way to obtain a jet drive powertrain would be to get a used or wrecked jet ski. The advantages of going this route is having a matching engine and drive designed from the start to work together and is already marinized. Doing an EJ20 is definitely a good option in my mind but it will be a bit more work and probably a bit more money, but definitely doable if that's what you really want.
So where do you want it to go from there Doug? :D
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

irie E
Posts: 23
Joined: Sun Dec 18, 2016 2:35 pm

Re: Starting my first build with a jet TNT

Postby irie E » Thu Jan 26, 2017 2:37 pm

How goes this project? That's a pretty sweet powerplant you have for your build!

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Fri Jan 27, 2017 12:01 am

Hi Dom, thanks for stopping by!
I lurked your post when it first popped up and I'm impressed with what you've accomplished with it. Nicely done!
I've never had any hands-on experience with the surface drives but I'm familiar with them through researching them out of curiosity when the Arneson drives started gaining popularity. I even spent some time on Mercury's attempt with the long defunct Blackhawk drive. Teaming the surface drive with electric power like you have is very cool!

The TNT project got put on the back burner for a bit, simply because I have too many irons in the fire. I have a couple engine builds with head port and flow work that I committed to before I started the TNT and they both got the go ahead this winter and I'm also in the process of throwing a fuel-injected LT1 350 and overdrive transmission into a little 2wd '91 S10 pickup for myself (needed something to haul wood with and also pull the TNT when it's done.... :lol: )

I've been picking up tools and equipment along the way and I did manage to pick up the stuff to reloft and re-fair the hull design so that's going to finally happen here in the next couple weeks if everything works out, then I start building. I'm even toying with the idea of turning the TNT into a tunnel hull.... just a thought.....

Thanks for putting up with my rambling :D

Dave
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Fri Apr 07, 2017 7:58 pm

Hi everyone.

Haven't had an update in a while with things going in 8 different directions at once, but now I'm getting my focus back to the build and I thought I'd​ stop by and say hi and update.

Well, when I jumped into the deep end, I didn't realize how "deep" the deep end could get. :shock: :shock:

I started out to build a practice boat to gain build experience and play with until I got to my goal of building a V-drive Tornado with a 6.0L LS engine. But, with me being me, I decided that I wanted something a little different, so I had the bright idea of building a jet TNT. Only issue there was that I ended up with a 165 hp turbo Honda 4 cylinder PWC as a donor for the build (as you all have seen). So I've been in the process of engineering all the necessary changes to the design to make it happen.

In the middle of all this, I had another bright idea (I gotta stop doing that....) that since I kinda modeled the boat after some of the jet drag tunnel boats that I fell in love with growing up, why not go whole hog and turn it into a tunnel hull to complete the package?????

So, at this point, I'm not only taking an 11' outboard runabout, stretching it to 12' 6" and adding an 18" pump setback pod just to fit "almost" too much power into it with the Honda, I am, with the much appreciated help from a racing tunnel hull design guru that I've met recently, now modifying the TNT into a Mod-VP style tunnel hull.

........I think I may have exceeded the limit on my "dare to be different" card with this one......

Happy sailing..... :D

Dave
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Sat Jun 24, 2017 8:47 pm

Hi everyone!

Looks like the forum has been really busy lately with some beautiful builds, very exciting!

I just wanted to update on what's been happening with my project......

I finally have the hull modifications nailed down after spending a ton of time learning the ins and outs of tunnel hull design (I never realized how involved this process was, but it was very educational and a lot of fun), and the construction details figured out on how to actually build this bugger, I'm currently finishing up the bill of materials so I know exactly how many pennies I need to spend to get this little ball of crazy rollin! :lol:

While I've been working on the finances for the materials and stripping the jet ski so I can cut it up and dispose of it and gain some build space, I've also decided that I wanted to render the TNT as a 3D model so I have a good idea of what I'm going to end up with and what would need to be changed before I started the actual build so......
.....I spent some time gaining a crude understanding of the Freeship program to model the hull, I mapped all the data points from the TNT patterns that I knew were going to stay correct on the build and created the data points for the mods and basically lofted the design out in Freeship, then I exported it into the Blender program and "crash-coursed" Blender to try to make it as representative of the finished product as possible. I'm still working on adding the details but I wanted to at least get these on and update my thread :D

Note: I'm still not completely sold on the big obnoxious "alien-head" Pro Stock areo scoop, but with the top of the coamings being 17" and the top of the valvetrain cover being 24" tall, it's the only thing I've found commercially available that would cover the engine....... any thoughts?
Attachments
DSR Jet TNT white1.jpg
side view w/ engine cover detail
DSR Jet TNT white2.jpg
chine and tunnel detail
DSR Jet TNT white3.jpg
tunnel and center pod detail
Last edited by DSR on Sun Jun 25, 2017 12:39 am, edited 1 time in total.
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Sat Jun 24, 2017 8:50 pm

.......... and a couple more............

Thanks!!
Dave :D
Attachments
DSR Jet TNT white4.jpg
transom w/ drive extension pod and tunnel detail
DSR Jet TNT white5.jpg
top view
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

JimmY
Posts: 459
Joined: Sat Jul 30, 2016 11:08 am
Location: Brighton, MI

Re: Starting my first build with a jet TNT

Postby JimmY » Sun Jun 25, 2017 5:07 am

DSR wrote:I'm currently finishing up the bill of materials so I know exactly how many pennies I need to spend to get this little ball of crazy rolling

Then double it! :lol:

Nice CAD work, looks like you've worked out the extra length and kept it fair. The scoop is a cool idea, and would be pretty easy to graft on. It kind of looks like the big unlimited hydros with the jet intakes. And since you'll be in the same racing class... :shock: You seem pretty artistic, so you might do just as well carving it out of foam and glassing it.

Let me know if you need any scrap 1/4" plywood for gussets, I've got a bunch laying around.
-Jim
Nothing says poor craftsmanship like wrinkles in your duct tape!

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Sun Jun 25, 2017 12:58 pm

LOL!!
Hi Jim. Yeah, I know what you mean. I have the markings worn off the "X" and the "2" keys on the calculator already. :roll:

The scoop is kinda growing on me the more I study it. I think the curves and general shape of it actually do seem to fit in with the overall look and feel of the boat. I guess I could build something but I don't know if I could come up with anything better looking. It's available from one of the vendors that I use, it's hand-laid fiberglass, weights less than 7 lbs and I can buy it for $159. I don't think I could come up with anything better for the time and effort it would involve (?)

I really appreciate the offer on the 1/4" but I don't believe that I'll have any smaller pieces of the 1/4" in the build. I'm taking a page out of the boat building book and I'll be laminating the bottom frames across from chine to chine in single pieces front and back as Glen described for the faster runabouts to keep the bottom frames from splitting so all the gussets are pretty big. I have a feeling that this thing might end up falling into that category (mebbe?......).

The Squirt is looking awesome! I really like the asymmetrical look of the dash. A very nice touch!
I measured my band saw and it'll only do 9", otherwise I'd be happy to have you come over and resaw the Mahogany. Sorry I couldn't help with that.

Thanks Jim!
Dave :D
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

Denon Osterman
Posts: 466
Joined: Thu Jun 22, 2006 8:58 am
Location: toronto, CAN

Re: Starting my first build with a jet TNT

Postby Denon Osterman » Tue Jul 18, 2017 7:52 pm

Hey Dave,

Man, can't believe I didn't see this sooner - I normally only check the "power boats" section these days but this is one awesome build! I really like what you've done with the bottom of the hull - that thing is going to fly. Do you have trim on the jet pump?

A (not so) crazy suggestion for the scoop...ditch it. Ditch all of it. Surely you're not gonna box in that 6.0 LS in your tornado...and as we've all seen, the honda power plant looks pretty nice! I think it'd be pretty cool to leave it open like the big boats do, but that's just me.

I did a very similar thing to you, starting with a TNT (albeit bone stock) and then moving onto a more challenging build (the current rampage). The things you learn on the first one are invaluable in helping with the second. The biggest lessons that stuck out for me were 1) laminate your chines. I'd rather have 3 chine laminations than 1 cracked one, and man is steam bending them annoying! 2) Rig *everything* before you put on the deck, especially in a small boat like the TNT. You don't know discomfort until you've tried to wire a bow light in an 11 ft boat with the deck already on, frame 3 digging into your back as you try and hold the flashlight in one and and the crimping tool in the other... 3) Epoxy does not stick to all stain, and paint hides all screw ups :wink: 4) There's many ways to skin a cat, and someone on the forum already knows the best one! Particularly applies to things like fiber-glassing, finishing work, etc. 5) The deep end is infinite, but so is the fun! :D

Congrats on starting such a sweet build, and take lot of pictures to keep us all posted - I really like the "modified" builds because it's always cool to see people add their own little touch. Plus this one is fast, and jet driven, which is right up my alley :D

Cheers,

Denon

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Tue Jul 18, 2017 9:53 pm

Hi Denon, thanks for stopping by and checking out my project!

Yeah, the pump does have cable adjustable nozzle trim on it (one of many reasons I chose an R12X to move this thing....). I'm planning on using an electric actuator on it with a trim switch on the steering wheel, just like the grown ups do. With the nozzle wedge I'm using, it might even throw a decent rooster.... :lol:

I also plan on using hinges on the engine cover that will slide apart so the whole engine cover comes off and I can run it either way. Actually, that big red valvetrain cover and the polished stainless water-jacketed exhaust from the turbo to the dual tips that I'm fabbing might look decent sticking up over the coamings now that you mention it (I'll just have to make sure the rest of the engine bay is purty if'n I do dat.....)
And if this little water-bound go kart turns out as nice as I want it to and runs the way it should (and it better with all the time and effort I've put into it so far!) I'll be a happy camper!
I'm pretty sure I've got everything covered as far actually building and rigging it (I think my OCD and myself have built it a hundred times in our head :D :D ). Between the forum and Glen-L's books, there's been a tremendous amount of information and ideas for just about any questions that I've had and I know this build wouldn't even be possible without Glen-L and the wonderful people here on the forum!!

Thanks Denon!!
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

Denon Osterman
Posts: 466
Joined: Thu Jun 22, 2006 8:58 am
Location: toronto, CAN

Re: Starting my first build with a jet TNT

Postby Denon Osterman » Mon Jul 24, 2017 5:04 pm

Hey Dave -

That all sounds like a great plan. Throwing a rooster is half the fun! :D

I think an engine that nice is worth showing off, and given the attention to detail you're going through so far making the rest of the engine bay look up to par shouldn't be too tough. I think you'll be pretty happy with the results...it's hard not to be when you've built it yourself and nothing went wrong :)
On that note though, one other thing I forgot...I *hate* boat building nails. Everywhere the plans call for nails, I use screws. And for the screws, if you're using the bronze ones from Glen-L (which I recommend), having a tapered bit / counter sink to pre drill all holes with, and an impact driver to sink the screws, really helps get them fully into their hole...the bronze is quite soft and tends to strip the frearson head rather easily. On that note, the frearson bit from Glen-L helps too!

What stage are you at now, when do we get to start drooling over pictures?

Cheers,

Denon

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Mon Jul 24, 2017 9:14 pm

Hi Denon,

I really appreciate the tips and tricks you're giving me. Thank you! They're definitely going to be a big help very, very shortly.....

No build pics just yet I'm afraid. I ran into a little speed bump on the very last detail of the design. I'm doing a drop keel on the bottom of the center pod to keep the pump loaded at higher speeds and I thought I had the design figured out but I can't get the hydrodynamics to jive. So I'm back to researching and annoying the hell out of anyone that knows what needs to be done to get it right. With this little bugger actually being capable of 80+ mph and possibly faster, I don't want to take any chances if I can help it.
Once I'm satisfied with that being ironed out it's full speed ahead! (Yup, that was completely intentional :D )

You know, it's funny that I've done a lot of hot rod stuff in my life, but I don't think I've ever been as excited about a project as I am with this little wood boat. Go figure.....

And I will definitely be taking lots of pictures!

Thanks Denon!
Dave
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

irie E
Posts: 23
Joined: Sun Dec 18, 2016 2:35 pm

Re: Starting my first build with a jet TNT

Postby irie E » Mon Jul 31, 2017 5:30 pm

The renders look great! I'm definitely interested to see this come together!

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Mon Jul 31, 2017 9:25 pm

Hi Dom, thanks for stopping by!

As you probably have seen, I decided to make good on my threat to turn this bugger into a tunnel hull. :D
It was just an itch in the back of my brain until I actually put the words down on paper (well, computer screen as it were.....) and that's all it took.
I'm glad you like the renderings, I spent more time on them than I want to admit. Thank you!

I saw your latest video on your electric surface drive project. Looks like it runs great! Nicely done! What kind of speeds are you getting out of it now?

........it almost makes me wonder what would happen if I strapped a surface drive to the Honda in this tunnel hull..........

...... probably something very bad............ :lol:

Thanks Dom,
Dave
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753

DSR
Posts: 196
Joined: Mon Mar 21, 2016 8:11 pm
Location: Allegan, Michigan

Re: Starting my first build with a jet TNT

Postby DSR » Sun Aug 06, 2017 11:58 am

Hi everyone,

Just a mini-update.....

Actually starting to make some headway on the pump intake design (YAY!!). I finally found the owner of a company that builds jet-drive race tunnels that was willing to talk to me about the design and hopefully the issue will be resolved shortly so I can get on wit da bidness at hand :D

In the meantime, I got around to generating the Linesplan from Freeship and thought it was a pretty cool feature of the program so I thought I'd share.

DSR mini jet mod-VP linesplan.jpg
Freeship-generated Linesplan


I also scribbled out a partial cutaway view to get a better perspective of where things will be situated and how well they'll fit......

......... Oh, who am I kidding. I just wanted to see what I would look like sitting in the boat with my Blue Man Group outfit on........... 8)

DSR Jet TNT Linesplan partial cutaway view2.jpg


Red designates the engine and pump intake placement
Orange designates the two side-mount 5-gal fuel tanks
Yellow designates battery box location
And of course, me in my outfit

After doing this little exercise I came to realize a few things......

1) This boat is definitely going to fit in the "water-bound go kart" size category (I'm not a small guy so I'm gonna look kinda XXL sitting in it....)
2) I think it's gonna be a riot to run on the water
3) It looks like all the major components are going to fit exactly as I had planned
4) Removing and installing the battery is going to a "blast".......(note heavy dose of sarcasm.....)
5) I'm definitely going to add a quick-disconnect that I was planning on for the steering wheel so I can weasel my way in and out of the seat
6) And I am DEFINITELY going to leave my Blue Man Group outfit in the back of my closet when I take the boat out....... :lol: :lol:

Happy boating!! :D
Dave
DSR Performance - Home of yet another jet TNT build :D
Codename "Just A Little....."
viewtopic.php?f=23&t=29753


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