Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: pilot10 on August 04, 2009, 11:44:30 am

Title: R/C and Sea water.
Post by: pilot10 on August 04, 2009, 11:44:30 am
Hello you guys., Can any one of you clear up a problem that has showed its  head at my local boating lake., The problem being is,  the  lake  is  salt water, and I have been told radio signals will not pass through salt water, this information is a bit of a pain, as I have the Revell Gato submarine which I want to build as in static dive mode., But if this info is correct, it will be  a waste of time making it.   I hope I have been told wrong and hoping for the best  Cheers  Mervyn.  Pilot10
Title: Re: R/C and Sea water.
Post by: Martin [Admin] on August 04, 2009, 01:16:34 pm
I don't know of anyone running a sub in salt water but I suppose there must be some.
I've heard that 2.4Gig radio don't work with submarines.

It may be worth putting a 2nd hand radio (battery, receiver and a couple of servos) in a air tight sandwich box and dropping it in to see if it works... tie a sting around the box first!
Title: Re: R/C and Sea water.
Post by: Subculture on August 04, 2009, 02:06:53 pm
You can run in salt water, but you must build your boat so that some of the aerial protrudes above the surface of the water when submerged as the radio signal will not penetrate the highly conductive salt water.

A chap in the States does this. He used a length of brass rod about a foot long- this means your depth is limited to under a foot, in reality this isn't that much of a handicap, most submariners operate close to the surface anyway.

In the case of your Gato, as it's a small boat, I would use a length of plastic tubing, and run the aerial wire up that. Cap the end of the wire off with a drop of 24 hour epoxy or silicone rubber. You will also need a waterproof exit for the receiver wire from your watertight enclosure. Again araldite or silicone will work. Whatever you do, make sure that the aerial length isn't extended or shortened beyond the original length, else the tuning of the receiver may be affected.

Finally, make sure your boat is equipped with a failsafe on the ballast tank and if a dynamic diver the throttle. This will help guard against the loss of your boat should you dip below the aerial length. I would also budget for a leveller as this will make running at what is effectively periscope depth, a much more refined experience.
Title: Re: R/C and Sea water.
Post by: getemuphigh on August 04, 2009, 05:26:07 pm
In the manual for the Thundertiger Sub SB-1 it explains that the mechanical diving depth spec is upto 10 metres for the sub but recommends upto 5 metres for the radio equipment etc.
It goes onto say that this will reduce in different types of water such as clear fresh water, lake with plants etc, cloudly and salt water being the most dense.
As mentioned before 2.4 gig won't work under water so conventional radio gear is only recommended.
And have a safety device on the ballast tank/s so it will surface if signal loss or low battery occurs!
Title: Re: R/C and Sea water.
Post by: pilot10 on August 04, 2009, 08:59:22 pm
Hello  and thanks to all you guys out there who answered my cry for help, and so very quick too. You have given me a lot to think about and  also some of your suggestions to try out. Thanks again, Mervyn=Pilot10