nice work amigo. i've got to visit casa de Ron one of these days.

That is very nice you have so much power I would put a lot of ballast make it ride low in the water AND put out a wake.

Actually the jury is still out on the ' so much power' issue; testing will show if the 600 motors will have the power/torque, to spin the jets without burning up...

Regards, Jan.

Well, our monthly boat run was cancelled yesterday due to somewhat cold weather, and high winds. It might've been good for fast sailboats though... So instead, I stayed home and installed a whip antenna, since it will look nice, and should improve range. I decided I would run the boat at a local pond on Sunday, since the weather was forecast to be nicer.

So now, its Sunday - time for Initial Sea Trials. [8D] I figured I better keep it easy on the power, and perhaps pull the boat out after 4-5 minutes, to check check the sea-keeping (is it dry, or is it taking on lots o' water). At low power, I suspect the model is entraining some air thru the waterjet inlets - you can tell the motors are running well, but there's not a whole lot of velocity. At medium power, you can see the waterjet flowthru at the transom improve, and the boat starts moving out well. At this point, I noticed a waterjet died. [] So I brought the boat in and inspected it.

Everything looked okay, so I swapped out the fuses in both motor, to the next size larger (25 amp). I was using 20 amp fuses, which is what I use on my other boat.

Boat goes back in the water, and I had a decent run. [8D] I also put about 1 ounce of lead strip on the aft deck, way aft, in attempt to keep the waterjets away from the waterline. You could see the waterjets operated a bit better at low speed, with less entrainment. I was actually kinda ready for this, since I did a "bathtub test" a few days ago. [8D]

The steering was behaving nicely. I don't think I'm gonna play around with throttle mixing - atleast yet. I ran the boat to full power in short amounts, and would bring the throttle down some, to let the motors or speed control cool a bit. I got a couple pics of the boat while at slow and medium speeds.

Hi Ron,

Good thing the fuses are there...
No big surprise you managed to blow one, as even 600 motors can draw 25A+ when getting out of the hole.

How were the motor and ESC temperatures after the full throttle runs?
(Actually, the ESC's have to work harder at part throttle, going flat out makes them act as a 'on-switch')

Regards, Jan.

I noticed after getting back, I had some algae slime in one of the jets - I wonder if I picked something up which caused the fuse to pop initially. Motors were not hot, so the water cooling is evidently helping some. The LiPo packs were only slightly warm. I can't move the LiPos aft any further, so I'll probably stick the lead on the inside transom, and leave as is for now. I'll keep the Graupner 600s in here for now, but will consider the 700s down the road after more running (if the motors seem to run hot). I like how the boat turns to - on my coast guard utility boat, the model has a deep long keel, which I suspect tames the turns, and keeps the radiuses large. The hull on this boat is closer to a deep vee hull, and the boat leans into the turns much nicer.

Now to get back to adding the other details on the model. [8D]

Hi Jan,

As to the temps of the goodies inside... I could put my hand on the motors, and I'd consider them to be very warm, but I wouldn't have to let go of them. On my coast guard boat, without water cooling, they would get hot and would have to take my hand off. The next time I run both models simultaneously, I can use my IR temperature device to get a better idea of the temps. I'm happy the motors didn't seem to want to burn up. I would think with 700 motors, and with the batteries you suggested, the boat would really fly!

I don't have a lot of experience with LiPos, so I'll probably keep the boat running pretty moderate for now... I think I've read if the packs are getting hot after running them, you're pushing them too much.

I've added a few more goodies to the boat now, like the windscreen, the guns, anchor, etc. I also added another light on the inside. I need to get a pic of the boat at dusk to see what it looks like, in the water. I also got some neoprene fuel tubing, which I've slitted along it's length, and attached it as a rub strip around the boat's perimeter. I've realized I can move the battery pack for the lights to the boat transom (actually velcroed to the lower side of the aft deck) to replace the lead I was using, to keep the tail end down a bit.

I'd like to add a few more bits to the model to make it more busy though. I also need to work on the figures. I wish I could find some figures to install that are a bit larger than the 1/35 guys I currently have. Hmm...

Looking good Ron.

Man, that is one cool boat,you just inspired me to do something similar if not the same, few weeks ago I swapped with a guy for his Thor,but when you do business at night in front of the corner store,you are in for surprise,sure enough, in the day light (just like a hooker) it looked totally ravaged and sloppy. I'm going to strip that boat and start a new,thanks for a great thread.

That paintjob is badass, the faster it moves the more fitting the paint will be!

completely understand the thread is 7 years old, but I need help to understand the water jet motor mount.

I got one thor recently, but I am not sure if it has stock original waterjet, the one I have cannot bolt on a 550 motor.
There are two mount hole at waterjet, but they are too wide for 550 motor mount hole, which is 25mm apart.
Original owner used two wood block to glue the 550 motor in, motor soon start to spin, need to either redo the glue or build new motor mount

Hi modeleryang,

If the mounting holes are 29 mm apart, the jet is intended for a 700 motor, which is a better option than a 550, which will struggle under load.
Even the 700 motor needs to be watercooled, as turning a jet is considered 'hard labour' for an electric motor.

If you don't want to spend the money on 700 motors, which tend to be rare and cost a lot, you can also go for a brushless motor, more power for a less money.
Downside to two brushless motors is the fact you'll need an ESC for each motor.
You can go for an outrunner (with a watercooled mount) or an inrunner, but due to the 29 mm spacing, an adapter of some sort will have to be made to get everything to fit.

Let me know if you have more questions.
Bigger pictures oriented the right way would be nice too...

Regards, Jan.

thanks for your reply, you are right, I remeasured the jet, it is 29mm apart. yes I will have to do a adapter from 29mm to 25mm now.