Hi robbertderouw,

Well spotted, the 'Grimmershorn' it is in my Harbour.

harbour/40693#google_vignette

Nice Grimmershörn😉

I hear that CB90! Almost lost my restored Kyosho Wavemaster due to taking on water. Fortunately, got her back to the Nick in time or she was headed to Davy Jones Locker. Time to break out transparent caulk. I was shocked that I missed an aft seam near the out board. 🙄

Hi Roy, thanks for the reply.

Yes, indeed the motor and ESC are expensive but they are worth the expense.

Thanks for sending me the detail photos of the propeller and the rear parts.
I asked you to see if a method that I tried to keep water out was possible (in addition to using grease).
However, it is not applicable in your case.
Basically it consists of this, I model a small gasket using silicone (silicone glue). It's not easy to explain just in words (a drawing would be needed).
The silicone sticks to the fixed tube and adheres to the propeller shaft without sticking to it.
To prevent the silicone from sticking to the propeller shaft, you need to sprinkle it with soap (dish soap is fine).
With your soapy finger you can shape the silicone.
Once dry it will not stop the axle from turning but it will be tight enough to prevent water from entering.
After some navigation this gasket must be replaced.
It should be considered more disposable (single use) than fixed.

This method is not a replacement but an addition. However it worked very well for me.

I would use silicone grease on the shaft, but that is just my opinion. As that's what i use on my boats. Silicone grease is a water resistant one. But to each his own we all have different opinions. I stopped using other greases as I found they tended to gum up and then solidify.

I have an old bath at the bottom of the garden for boat testing, I put that there as when I used to test my boats with IC engines it didn't stink the house out being near the back door. Not like my dad when I was a kid starting and running a ED Hunter 3.46 cc in our bathroom. My mum didn't even say a word. ut after 15 minutes he stopped it as even with the small window that we had in there it was full of exhaust smoke and fumes. That was a one off, after that it was only ever run on the pond or with a gravity fed cooling water pipe in the garden

Roy thanks for your feedback on the flex shaft. Len

Hi Roy, it seems like a very valuable electrical setup, especially the motor and the ESC (they are very expensive I imagine).
The brushless motor has remarkable performance.
Can you attach some photos of the propeller area and the point where the water enters?

Hi Len1,

It is possible that a cable can be damaged if put in reverse at full power, but this has not happen to me personally.
I never use full power in reverse on a cable drive, some ESCs are set up to limit reverse power to about 50 percent, but not all do.

one of the main problems with cable drives is corrosion due to poor lubrication and/or use in sea water.

Regards Roy

nice motor mount. Do you have any issues when using a cable propeller shaft when you run it in reverse. Does the cable start to unwind because it is turning in the opposite direction it was wound when manufactured? Len

I think I read an article on this site where the person uses outdoor wood glue and tiny foam balls for flotation. The glue waterproofed the foam and held it in place. I just couldn't find the article.
RR.

Hi Roy, allow me to tell you my opinion.

To guarantee a buoyancy reserve it is not essential that the spheres are glued together.
The important thing is that, in the event of a leak in the hull (or in any case if water is entering the hold) they remain in position to carry out their task.
To do this, they just need to be placed in a closed compartment.
However, in the event of flooding, even if the spheres cannot leave the boat, water will seep in between them.
Geometrically the spheres do not have a total occupation of the volume and the space between them is quite conspicuous.
To understand this, look at the images.
In the second and third attached images a parallelepiped measuring 36 x 24 x 24 mm is represented.
So its total volume will be 20736 mm3.
Let's take into consideration spheres with a radius of 3 mm (diameter 6 mm).
A maximum of 96 spheres of this diameter can fit inside this parallelepiped.
A sphere with a diameter of 6 mm has a volume of approximately 113.1 mm3.
Therefore the volume occupied by all the spheres will be 10858 mm3.
Well if you make a proportion between the volume of the parallelepiped and the total of the spheres you will realize that this is approximately 52.36%.
Logically this proportion is always the same, whatever the number of balls taken into consideration and whatever their diameter.
This means that if water gets between the spheres or if the glue you use is heavier or slightly lighter than the water, you will have reduced (almost halved) the floating effect of the spheres.

In fact I prefer light material but not in spheres. Compact, square shapes that I can cut out. They will fill all the spaces (not leaving them available for water) and will be stuck together without the need for glue.
In any case, if you still want to use the spheres, you could put them in various hermetically sealed bags.
I don't know if I managed to explain myself well with the translation.
I hope so.

Hi Roy, this system seems better and safer to me than expanded foam, even if by now you understood what the risks were and how to manage it.
I hope that the glue you used for the balls is not too heavy otherwise it will greatly limit the floating effect.

an interesting buoyancy method. You must let us know how it works out. 😉

Hi Jumpugly,

Interesting!

https://speedace.info/Water_Speed_Records_Pioneers_Seas_Oceans/Crusader_Kongsber

That's cool CB90! Reminded me that John Cobb's Crusader was filled with Ping Pong Balls!

I don't know if you can still get then, but I bought from B&M some what they were selling called swimming snake's I think. They were in the children's toy isles. They were like those polystyrene lagging tubes but not hollow. Also came in different colours. they were a lot longer than those grey lagging pipe ones and would go all the way down the side of the boat.

She's robust and she's gonna FLY!!!!!!!!! 👍