Help designing a submerged ball to guide my wife lake-swimming

This is the perfect crew to ask this: I need help designing an underwater ball I can tow behind a kayak or SUP or canoe. My wife needs to swim with a snorkel because of neck mobility issues, but she is like a barracuda when she gets going! In the summer, my son and I go to local ponds and lakes for him to train for triathlons: there are submerged trees and branches and rocks and I guide him away from them. But with my wife, she could not see me at all, even if I paddled right beside her.


her field of vision is somewhere between 90 degrees straight down, and about 30 to 45 degrees down from the surface.
But she asked if I could tow a “ball” behind the canoe, one that would sink, but not be too heavy.
Any ideas from the think tank? I’m going out to test things today like a bottle of water, or with some pennies in it. I wonder if there is some material that is just a little denser than water that could be about dodge-ball size?
thankee!

What about using one of those styrofoam belly boards and suspending a waterproof PFD light from it. A lot less drag.

1 Like

Cool idea! Do you know of a pfd light that would sink (I realize, this is probably the exact opposite of what people normally shop for in pfd/canoe safety devices :stuck_out_tongue:)

Not specifically, but most PFD lights are pretty compact and are not designed to float. You could always add a bit of weight if necessary. I thought of a PFD light rather than a dive light because a PFD light generally has 180° coverage instead of just shining forward.

1 Like

How about one of those swim toy torpedos that you throw underwater. We used one with our kids, they went quite far, so little drag. they come in a variety of colors and are not that expensive, cheaper than this example I have linked.

Amazon.com: Torpedo Strike SpinFin 10.25" Large Ultra Premium Pool Torpedo Rocket Spins & Glides Up to 30 Feet Like Underwater Football for Under Water Passing Games Underwater Torpedo Diving Toy Glider (Pink) : Toys & Games

they are designed to sink, but not go straight down, so attached to a tether they could work quite well, and if a bright color you might not need electronics, like lights. Or you could probably attach a light to it if needed.

You might need a swivel on the tether, I forget how much they twisted as they coasted.

1 Like

Does your wife use a snorkeling snorkel or a swim snorkel? I wasn’t a “swim team kid” and didn’t even know about the latter until I saw the video of Katie Ledecky using one while swimming a length of the pool with a glass of chocolate milk balanced on her head. She didn’t spill a drop, of course. :rofl: I now use a snorkel because my technique is terrible and haven’t mastered breathing to the side. Let us know if you come up with a solution. TY

1 Like

!!! Katie Ledecky swims faster than me even with a glass of chocolate milk on her head! Gotta show this to my wife…

1 Like

I was going to suggest the same toy - this link is for one that is designed not to spin. The fins are straight and it has less drag:
Amazon.com: Torpedo Strike DartFin 11.25" Pro Size Ultra Premium Pool Torpedo Rocket Glides Up to 40 Feet Like Underwater Football for Underwater Passing Games Underwater Torpedo Large Diving Toy Glider (Yellow) : Toys & Games

My brother made a version of this back in the 60s. He used a wooden baseball bat as the hull of a model attack submarine about a foot long, with fins and a conning tower, weighted at the keel to be just slightly buoyant. It could travel all the way across a pool submerged, then would slowly surface as it slowed down. It hurt like hell if it ‘accidentally’ caught you in the back, wonder how that happened…

1 Like

Prototype 60’s toy! Dive dive dive!

Thanks to everybody for these great ideas: here is a video of our trial runs: we tested the lighted pool sinker, the flashing PFD light, the pool torpedo, and the bottle of Powerade (blue) weighted with stones and sand, wrapped in white duct tape.

So far, the Powerade has been at just the right depth and angle for lake swimming in our dark pond at Gambo Dam in Gorham, ME.

We will do more live testing (one at a time) to find the right length of rope, weights, etc.

I must be using the right bait, because I caught a beautiful mermaid!

5 Likes

Thanks for the update!

1 Like

This is really interesting. Maybe you need an LED inside that bottle! Thanks for sharing this little adventure.

1 Like

I think a steady light would be less aggravating than a strobe.

1 Like

Look at downriggers for fishing to control the depth.

2 Likes