Abc Hobby Jet Ski Hull Conversion

[damfurst]

I have a couple of these hulls sitting empty since I gutted them for their drives to use in some other projects. I started earlier this fall working on one of them. First I fiberglassed the major holes with 2 layers of glass. This turned out fairly well for my first time working with it. Then I took the motor, motor mount, esc, etc. from another hull I had tried building an airboat from and started to work mounting them on the hull. Made a deck out of 1/8" basswood with 2 access hatches. Motor & motor mount attached to rear one. I know these are nothing fancy, but I'm still wanting to see if this will even work. I'll probably get a vid later this week when things warm up. For now here are some pics. http://forums.offshoreelectrics.com/album.php?albumid=139

[damfurst]

Here's a short vid of it running for about 10sec and then it flipped. Search & rescue ensued as it floated downstream. Will a get a better vid of it running soon.

http://www.rcuvideos.com/video/Abc-Hobby-Jet-Ski-Hull-Airboat

[Steven Vaccaro]

Running in rivers is tough. Especially that quick flowing river you are running in. I would like to see a video of the boat fighting the current.

[damfurst]

It's kind of strange that it's happened twice now. I can have a decent run on the creek with this boat 5-10min in length with no problems. Turn on the camera and it flips inside a minute every time. I'll try and get a new vid today of it running through the waves and current.

[Diegoboy]

balast the lowest point in the hull with BB's and epoxy.

[damfurst]

Thats a good idea Diegoboy, maybe I'll make some short pieces of pvc pipe with bb's glued into them and then velcro them to the bottom. That way I can move them around until I find the right fit. For now I got another run in yesterday before snow returned today. Sorry for the poor quality of the vid, but no camera person makes it difficult on creek. My rudder was loose too which made it hard to turn (since fixed) and I broke the prop at the end on a low overhanging tree branch. But I didn't flip it at least. http://www.youtube.com/watch?v=eVKeGZQbJxo

[damfurst]

Well been working on some mods on this hull. There was kind of a brake rib on the bow that everytime I would break through a wave on the creek would splash and would slow the boat down. So I sliced it off and fiberglassed over the large gouge. I thought too I would try putting an air rudder on and so mounted a servo above deck and thought everything would be set. I also made some of the BB/epoxy filled pieces of 3/4" PVC and attached 2 of them with velcro to the bottom of the hull towards the back. This I attribute to Deigoboys suggestion which was a really good one.

Results: The bow modification did stop the speed reduction so that was a plus (it also didn't leak)
The BB/epoxy pvc kept if from rolling over in the turns. Thanks Deigoboy
The air rudder didn't work worth crap. I think it may work out on the pond, but not against the current in the creek. So I tried a smaller water rudder(off a mini-v) turned great to the right but not left. So I mounted an extra strut off a SW26 and just like red riding hood it was just right. Now I can cruise up and down the creek at full power and turn either direction and not have to worry about capsizing. Not a speed demon but still learning in that department. Anyway here are some pics of some of the mods. Will try to get vid tomorrow down at the creek. Supposed in the low 40s all week. Almost feels like spring to us that live here.

[Diegoboy]

Looks and sounds sweet. Great job. Do you have a pic of your balast installed? I liked your idea of making it adjustable rather than fixed.

[damfurst]

Got some video yesterday and hopefully it will show how it's running now http://www.youtube.com/watch?v=vj9XWgEPhH8 I did flip once in this vid but because the rudder hooked a loose tree stump that's barely under the water. Not the drivers fault, ok maybe it was but not because it wasn't handling well.

Diegoboy here's a couple of pics of the bb weights I made. I made 2 different sizes with 4 of the shorter ones and 2 of the taller. Just used paint masking tape on one end, filled with bb's and poured the epoxy in. I have mine standing on end but the taller ones could easily have the velcro on the side and be laying down in the hull. There are also some pics of the water rudder before and now too.

[damfurst]

Since my last post on here I have made a couple of more mods. I extended the motor mount by 1 1/2" so I could run a larger prop. Before an 8" prop was the largest I could swing. Now I can swing at least a 10" and maybe an 11"(haven't tried that though). With the 10x7 it does go faster, but the torque roll is worse again. I had to add another 3.3 ounces of bb's to the hull to keep it from flipping. I did try an air rudder on the pond also, but it did no better than on the creek. I guess it will only be a water rudder for this boat.

I tried a 2000kv inrunner motor(the one before was a 1000kv outrunner) with a smaller prop. This motor was only rated for 10amps so I knew it would be short lived but wanted to see what it would do nonetheless. I used a 6x5 prop and it moved right along. Was as fast if not a little faster than the other setup with a 10x7 prop. So I had to try a bigger prop. I couldn't get any of the my 7" props on so I impatiently put an 8x6 on. Man what a difference. It was considerably faster without the torque roll of before set up. It lasted 1-2minutes and then smoke on the water from the motor. :smile: But it was worth the experiment and the knowledge gained. I need to find a higher kv motor around 2000kv that can swing at least an 8" prop without frying. I'm sure they exist. For now though back to the 1000kv. :thumbup1: