Hi looking good, I've been looking at jet drive but only an idea at moment.
Phil

Thanks. Yes, I really like the lines of the hull but the superstructure was crying out to be updated.

Hopefully will be a quicker build than my Faireys.

That looks very sleek !

Having built (well still building!) a number of models with a traditional prop shaft and then one with a stern-drive (all Faireys including a Swordsman) I wanted to do something different (for me).

I'd already produced some drawings based on the Lesro Stiletto/Rapier hull and various more modern superstructures and chose one of those and altered the drawings to suit the water-jet. Bit more complicated in some ways but hopefully it won't be too bad and has the advantage of having the drive, steering and motor all as one unit.

Thanks ChrisF for this information and photo.
When you make this model I will be very interested because I have never made water jets and it seems like a very complicated matter.

Alessandro, like Doug I don't use water-cooling on my builds, even though some of them are quite fast. But for a future project I'm using a water-jet which uses a brushless inrunner motor and comes with a water-jacket and take-off point on the drive for the water supply so it makes sense to use it especially as the motor will be working hard sometimes. Also be good to do a water-cooled installation for the first time.

Anyway, photo shows the water-jacket fitted to the motor.

Chris

Glad to clarify Alessandro.
Sorry, can't help you with a photo.
As posted here before I have never needed one😊
If the ESC, motor and prop are properly matched a cooling jacket should not be necessary on a scale model. As I said; I don't build racing boats. I'm not looking for speed records😁
Ciao, Doug😎

Thanks Doug, I could imagine something like this but it's better to clear up any doubts with your explanation. If you have a photo that's even better. Just out of curiosity because I've never seen them for small electric motors.

OK Alessandro,
Let's start with 'jacket'.
Denk an eine Jacke. Du ziehst sie an, um dich herum.
A 'water jacket' ist eine Jacke für E-motoren😉
which forms a heat sink around the motor with water flowing through it to carry the heat away.
They are often made from coils of brass or copper tube tightly fitted around the can of the motor. So obviously you can't do that with a brushless outrunner!😮
Alles klar Herr Kommissar?
Cheers, Doug😎

Hi Doug and Roy, I have carefully read your assessments of the problem and your advice.
I think I understand almost everything; the only thing that I certainly mistranslate because it leads me astray is the "water jacket".
What is a "water jacket"?
Sorry if the question is trivial but google translate doesn't help me much in this case.

Absolutely Roy.👍I agree totally.
A water jacket only treats the symptom.
It does not cure the root cause 'disease'.
Also, we don't want a pond full of boiled fish do we!
I don't build racing boats, only scale, but I do like my ships and boats to run at a decent clip.
And to have good acceleration to be able to avoid potential trouble.
So far🤞 I have never needed a water jacket and neither motors or ESCs have ever got more than slightly warm.
Cheers, Doug😎

Hi Scamp good advice on water cooling but it may be hiding the problem in this case.
Also the fishes might like their water cold!

Roy

Have you ou fitted a water jacket? This works on my 4 ft fire tender fitted with a 40mm 3 blade brass prop.
Scamp

Hi Schmango, I agree with Doug. All the heat in the motor is from the battery and smaller prop would be a good idea.

As far as speed goes I would fit a much smaller prop and work up in size until it just planes nicely. It will use less current and the motor will stay cooler. Is the battery hot as well?

Doubling the current will not double the speed!

Roy

Looks really great on the wet stuff Schmango👍 Good work.
Re Hot motor-
Assuming that the Johnson 970 is rated for 12V then I suggest that it is being overloaded by driving a prop that is too large. Thus increasing the current draw with no significant power/speed advantage. Don't know what size prop you are using but try the next size down, maybe also with a lower pitch. I.e. if 45mm try a 40mm etc, etc.
Too large a prop is the classic reason for overheating of the motor.
Cheers, Doug😎