If you own a White's Dual Field PI or BeachHunter ID 300 you must read this post!

[Horsesoldier]

Here is the answer to the coil bouyancy problem. It's called a "Ballast Ring" and can be made for less than $5 with material from any hardware or home improvement store. The prototype worked well in rough surf. Please post your fileld test reports. If you have any questions please don't hesitate to P.M. me. Thanks.




http://www.youtube.com/watch?v=9Z8t-mk1lfg

 

[hobbes_lives]

I'm gonna have to call shenanigans on this one.

Coil buoyancy is dictated by the average density of the coil as compared to the density of the water. Adding a water filled tube to the coil is not going to make it more neutrally buoyant. As a matter of fact, freshwater is less dense than saltwater, so it would actually be a tad more buoyant than before.

Perhaps I'm missing something. Can someone please explain how this could possibly help with a coil buoyancy problem?

 

[Horsesoldier]

The difference in density in this application is miniscule. Plus, that is only a factor when they are mixed. Are you going to tell me that when you add weight to a material that is already "near neutral buoyancy" it will make it float?

 

[hobbes_lives]

It's not just the weight of the added material that you must take into consideration, it's the density of the material in comparison to the density of the displaced liquid.

I'll provide you with an experiment to try. Take a balloon and fill it with fresh water. Place the water-filled balloon into a container filled with the same fresh water. The balloon will generally float around at different levels in the container. This demonstrates neutral buoyancy because the water in the balloon and the water in the container are of equal density.

Now, add a good amount of salt to the water in the container and stir it up. What happens to the water-filled balloon? I can tell you, it will float to the top. This is because the density of salt water is higher than fresh water, demonstrating that fresh water is more buoyant than the salt water.

Adding positive buoyancy, your "Ballast Ring", to a neutrally buoyant coil will tend to make it want to float, not by much, but it will, scientifically.

I'd suggest that there may be other factors at play that cause the modification to seem to stabilize the coil. That's why I stated the following in my original reply to your thread:

Perhaps I'm missing something. Can someone please explain how this could possibly help with a coil buoyancy problem?

I'm happy if it works for you. I just don't understand why it would, or how it could. :?

Now, fill it with water (or epoxy) and sand, make it easy to add and remove (for swinging out of the water), and I'd say you've got a winner!

 

[mike - in]

I solved a bouyancy problem years ago with a short piece of bicycle inner tube and white sand. Filled the tube partially with the sand, tied it into a dounut shape with a wire tie and slipped it over the lower shaft to rest on top of the coil. Worked great to keep the "floater" down!

 

[Ice]

I have seen someone do this only they put a little sand in the tube. It doesn't take much to work. Ice