Jet Boat Question

[ashley needhamParticipant @ashleyneedham69188]

Just a thought Andy, but you will have to put CONSIDERABLE weight in the hull to make it a semi submersible, which wont go well for overloading a waterjet!

Ashley

[John W EParticipant @johnwe]

just to pick up where Ashley left off on a previous thread – it took me a long time and a lot of searching to find out what you actually call those wiggly pushrod thingies – cos I needed one for my latest project and I ended up searching on the aircraft forums to find the correct name – SNAKES – Flexible snakes at that.

Here is a picture of mine, the one I am using, which at some point will be semi-submerged and require sealing. I am going to inject a small amount of grease into the sleeve before inserting the inner flexible push rod.

Ashley may pick up on the model I am currently building, as he has already built one similar.

Mine will either work or be a brick – a slow brick

John

[Andy Stone 1Participant @andystone1]

Hi Ashley,/ John, I get what you mean now by a snake, I bit like a morse/teleflex control as used in boats a fair bit, loads of grease should seal it from water ingress, Yes I realise Im going to have to use a lot of weight Ashley , probably have to use an SLA type 12 v battery to get some weight in there A bit of trial and error to find the right weight.

Ive not sure Ive heard of a submarine bellows Chris, whats its function and how does it work, ?

Andy

[ashley needhamParticipant @ashleyneedham69188]

John. Ashley has built something similar…..hmmm….

weight. When I built the Top Gear 007 car, I could not actually put sufficient weight inside it and had to glue sheet lead underneath. My dynamic diving sub is free flooding at the ends to reduce the ballast requirement.

Snakes, of the length in Johns photo should be fairly waterproof without grease. Bellows as referred to I think are just that, the wide end sits on a bit of tube on the hull (as a tight fit) and the small end usually has a very small hole in which the servo rod is a tight fit. Being corrugated as it were the bellows will expand or contract to move with the inner rod.

Ashley

[Richard SimpsonParticipant @richardsimpson88330]

Andy, are you able to see the picture I included? The bellows is at the bottom of the opening. If you can't see it let me know and I will take a better shot.

This is the type of thing I am referring to:

Linkage Bellows

With that one the aluminium spigot is bonded into the hull to provide a good seat for the large end of the bellows to sit in, which can then be tightened up with a miniature cable tie. The linkage then sits tightly in the small end and can be secured with a spot of silicone. The bellows simply expands and contracts with movement of the linkage rod.

As I mentioned, just another option.

[Andy Stone 1Participant @andystone1]

Thanks for your help, I can see now from your pic John after Ashley described it, Very neat and tucked out of the way nicely. I like the Idea of yours Richard it would do nicely, I have another solution though, A gland nut and packing, it would have to have a solid outer casing but that shouldn't be a problem, If the overseas postage wasn't so slow I would like the bellows though. Thanks for your help.

My water jet arrived in the post yesterday, Its got a 5mm shaft so I may have to make another coupling to suit a smaller motor. As previously mentioned It is a big jet

Andy

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