Anyone try attaching buoys with magnets?

jcamp

I'm thinking about installing a course in a river where state law would require me to float it and sink it with/after each use.

Instead of pulling up the course and clicking buoys on/off each time, I'd like to try attaching the buoys with magnets. The thought is that I'd have a sub buoy with a magnet approx. 5 feet down, and another magnet dangling on 5 feet of rope attached to the buoy. To install I'd just float up next to the sub buoy (which would have a large, bright-colored disc attached underneath it for visibility) and drop the magnet on the buoy down and the two would connect. To remove after skiing it would be a easy tug.

Anyone else ever try this? Is it doable? Any thoughts (besides mockery)?

PS: No, I have no idea how heavy magnets are and how large they would have to be to keep buoys in place. Feel free to enlighten me.

PatM

It sounds like a pretty ingenious idea. Hopefully it works. I would think the magnets like ones in the old slalom timers would be strong enough.

MISkier

Don't know how that would work, but I kind of like the out-of-the-box thinking. I would probably be careful with those magnets in the boat. I wouldn't want them near my ECM, ZO head unit, or other sensitive electronics - or my cell phone.

dchristman

The first thing that came to mind for me was this thread:
https://www.ballofspray.com/forum#/discussion/comment/376389

I picture 26 magnets on strings with balls attached in a boat sticking together and to anything metal in the boat. Actually, you would only need magnets on the subs and metal on the ball strings, so that would save you from that fun

Than_Bogan

Definitely you want to avoid the magnets sticking to each other. I had some ideas in mind for lessening that problem, but perhaps the "easy" solution is put actual magnets in the water, but just easily magnetized metal on the buoys. That way the things in the boat have no tendency to stick to each other at all! (Just saw @dchristman had the exact same though process.)

The other thing that might be a problem -- and I'd be interested in hearing about results -- is that magnetic force drops off very fast with distance, so the two ends you want to connect will have to be fairly close before they will do the autoconnect that you want. Obviously, stronger magnets will have a larger "attraction range," but long before you reach the point of dangerously strong magnets, you'll have to contend with a simpler annoying problem: That it will take a lot of force to disconnect when it's time to take the buoys away! And I don't think you'll be able to create any "pry" effect, so you'll be working against the direction that the magnetic bond is strongest.

But I think it's worth a try for sure! If you can get a visible float to target, and something very dense with an easily magnetized plate at the bottom, I can imagine the connection process being fairly smooth. And then if you can tune the magnets just right, maybe you can also separate them with a good yank at the end.

In principle (full disclosure: I have never tried this), a super-strong magnet that is behind a layer of something non-magnetic could get you more desirable behavior. In terms of the "attraction range," it will be essentially the same as the super-strong magnet all by itself. (You can't block magnetic forces.) But when it comes to detach it, it wouldn't be so close as to have created an overwhelming strong connection.

Good luck and definitely report back! Or email me if you need more useless ideas that should work on paper .

dchristman

Be sure to wear a helmet when you yank'em out!

A potential downside to the magnets in the water would be catching fishing lures and hooks. It might also inadvertently attract fishermen to your course area thinking it's a hot spot because they're getting a lot of bites.

Wish

Rust

BraceMaker

@Wish the ones on my fly fishing gear seem to hold up just fine even in salt.
They do need to be brought pretty close together to couple properly.

A few years back we were trying to do something where there would be a weight attached to the course ball and line and then a bucket/funnel to drop it into - we were working in pretty shallow water and the idea was that if you would set the buckets where they should be and then idle by with a boat and drop the weight down into the bucket - if the weights were say 6" around and the bucket is 12" around the worst a ball could be out of position would be ~3" any direction and then to retrieve you just drive up and snag the ball.

This was based on the whole PVC/sash weight self adjusting course idea - but when the water is clear enough to see its still hard to get a weight to fall straight down 6' into a 12" hole.

thager

I experimented with strong ceramic magnets in shallow water. Concept worked fine when you can see the other magnet but once visual was lost it was a crapshoot. Had to get closer than one would expect and if you went below the target magnet, the magnets then repelled each other, I gave up!

ToddF

https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwj7lYzSlr3tAhUB5rMKHUz9BFEYABALGgJxbg&ae=2&ohost=www.google.com&cid=CAASEuRoRsDDKD0mnK3EaZP-S1Amdg&sig=AOD64_1cUwFL0OrYI_8okz-s6I3n1gLvag&ctype=5&q=&ved=2ahUKEwi284TSlr3tAhWJq1kKHWPsAlMQwg96BAgBECc&adurl=
Could be modified to relase and with some sub bouy adjustments releasing the 6 turn balls could sink it more than enough to keep out of prop range

RGilmore

To get the kind of connection you would want, versus the high weight of magnets in general, you almost necessarily need to use rare-earth magnets . Unfortunately. rare earth magnets are extremely prone to corrosion, which is why they are generally nickel plated. Even so, underwater the nickel plating will quickly flake off, leaving you one hell of a rusty mess.

So you'd probably have to encase them in some sort of bedding compound in order to have them last more than one season.

Also, forget the idea of having a hanging magnet dangling off the top of the sub-buoy - you could find yourself "fishing" for hours trying to get two magnets-on-a-string to find each other. Instead, permanently affix the largest RE magnets you can afford to the tops of the sub-buoys, and smaller ones on the ends of the buoy lines. At 5-feet deep, your sub-buoys are gonna be safe from any prop strikes that could happen in a fresh water lake (unless they're running ocean liners on your lake).

And finally, you will quickly learn that two strong magnets can form a VERY secure bond that will resist the strongest "in-line" tug you can muster. However, they can quite easily be slid apart in a sideways fashion. So you're probably gonna have to devise a way to slide the buoy-line magnet sideways off the top of the sub-buoy

RichardDoane

back in the olden days of PP, we used to buy inexpensive ceramic magnets and cut/insert them into the foam style boat guides for the 1 and 3 ball markers, We'd also glue some to sub buoys for under the entrance/exit gates. Considerably cheaper than skier2skier. Look at https://us.first4magnets.com/ so many different types.

dchristman

I ordered magnets from this place https://www.kjmagnetics.com/ when I was trying to build a magnetic release binding. Watch your fingers! those powerful magnets can really hurt when they connect.

Than_Bogan

The thing @thager noted about them repelling each other if they get too deep sounds horrible BUT that shouldn't be an issue if only the in-water side is a permanent magnet.

jcamp

Thanks for the insights guys. Great info.

Quick question: Do the PerfectPass magnets float? Or is the foam around it just for strike protection?

WIRiverRat

I used a large magnet to find a chain that went down to our anchor whenever a buoy popped off. I think it was a 250lbs pulling magnet, fairly large. Rust on a galvanized chain quickly stopped that idea from working. After about a year the magnet would hardly hold on to anything. Passing waves would separate it. I now just have a piece of SS cable running to every anchor. I catch that with a grapple hook and snap on the buoy. Much easier.

Oldkier

How much current does your river have? Flash flooding?
Debris?
Commercial fisherman (catfish traps)
Barges?
I have been putting my course in for over 20 years on the Ohio River and lost it for all those reasons.
It sounds like you just might be on to something, I am very interested in how this works for you. Good luck!

ral

@jcamp , PP magnets did float and that protection bended the crap out of fins and wings whenever you went at the "right" angle over the gate buoy.

jcamp

@oldkier Some rapid water and debris in the spring, but things generally calm way down by mid to late June. Basically when the water starts to get warm anyway. It's a much smaller river than the Ohio (no barge or commercial traffic/fishing). The kayakers will be the biggest problem :-)

jcamp

Does anybody have an old PerfectPass magnet they'd like to sell me so I can do some experimentation?

Oldkier

Ski-it-again has some for sale under speed control

Oldkier

Just an fyi, I set my timing magnets 2 feet under the height of gate ball on different down line zip tied together, less chance of someone snagging or hitting them with their fin ect.

jercrane

What if you orient the magnets vertically (assuming discs) so when you pull the line to disconnect you are sheering the two magnets apart instead of pulling directly against the magnetic force direction. Per @Than_Bogan comments

I really dig this and will be very interested to see the final results as we are in the same boat in NH and hooks are a bit of a pain.

Than_Bogan

@jercrane Genius! Even if it doesn't end up working, that is some clever thinking right there.

WoodySkier

I think you’re overthinking it, the plastic clips are pretty easy.

BraceMaker

@WoodySkier - the problem most of us have isn't the attachment it is the retrieval. With the plastic clip method you have a bag full of balls and you snag and drag the course up and then you have to work your way down the nasty slimey mainline and booms finding every attachment rope and then pulling up the clip and attaching the ball.

However as I've been thinking about the magnet idea the problem becomes clear - to have enough tension not only would you need to drop the magnet down and have it connect but you'd have to push the balls underwater to get the magnets to touch so that when you released the ball it had some actual tension on it. And as you said if you have the rope in hand you might as well just use clips.

BraceMaker

Just a side note - if anyone out there wants to review this idea and play with it.

I'm a bit obsessed with an idea I had for a public water submersible course ever since a halloween party. People have been making these PVC linear pneumatic actuators where when you hit them with compressed air BANG up pops your coffin lid or whatever. However these are just made of two telescoping PVC pipes, some end caps and misc. fittings.

My idea is build these 5-10 feet long depending on water depth. At the bottom this would hook to a permanent anchor, at the top end you'd rigidly attach a foam sub-buoy. Internally you'd install bungee cord to retract the ram and pull down the subs. Installation would be connecting this at the bottom to a permanent anchor and then you'd use a diver or just swim down and you'd stake the air hose down into the bottom with landscaping staples.

Now when you applied air all the subs would pop up to the surface. You'd attach all your balls with bungie cords and then release the air pressure which would retract and tension the balls. If you had a compressor/vacuum like wally sinker courses use you could also apply a vacuum to the system and likely pull the actual ski balls down under water.

The beauty of the design in my opinion, modular, no mainline, air hoses can sink into the bottom over time unlike a wally as they don't need to come up with the course. No horizontal PVC booms that can get easily caught.

Vertical PVC "cylinders" would be resistant to snag as lures would not easily foul the pipe. regardless if water got into the cylinders or not the pressure would still extend the PVC as we're not relying on the air pressure for floatation we are just physically extended the cylinder so air/water does not matter.

MichaelGoodman

I attach my buoys with a piece of bungee I thought that if I put a large galvanized nail
on each bungee I could then fish it back up with a magnet and just hook the bungee
on with a clip. This way you only need one magnet have not tried it yet so not sure how
quick you can "fish" for the bungee but I bet it would work with a good sized magnet.
I leave my course in all summer but I thought it might be a good way to retrieve in the
spring with out getting in the water.