Here are some throw-able marks plans that were given to us by Tom Walsh , but designed by Marc Smith.
What you need:
12" galvanized carriage bolt
Braided carpenter string or similar.
4 links galvanized chain
2 split ring (keychain ring)
1 cuban yoyo
2lb lead slug i made my own i can provide the mold or buy this
1 2-3ounce pyramid or similar sinker
1 snap swivel
1 Shark float
i have recently been adding a one liter bottle shrunk around the buoy for added durability.
1. Grind bottom inch of carriage bolt flat, and cross drill a hole large enough for the split ring to pass through
2. Push carriage bolt through center of shark float
3. Install washer and both nuts.
4. Tighten nuts against each other as close as you can to the float, do not compress float
5. Install split ring
6. Brush paint buoy color of choice, include at least one vertical stripe contrasting color. I use electrical tape.
7. When dry, cut bottom off of bottle of tonic water slip bottom over top of of buoy, and then using a heat gun, carefully heat and shrink bottle down over buoy.
8. Trim bottle top flush with top of buoy.
9. Install chain links into split ring
10 Thread string through lead and then tie onto bottom most chain link. use CA to fix knot
11. Tie other end of string onto yoyo and wind string.
The pyramid weight is clipped on after you toss the mark in. This helps weigh the string down so it sinks on the shore line side.
I was contemplating trying this build with just a one liter bottle with no foam mark. Coat the inside of the bottle with paint let dry and then a screw eye into the cap, with some sort of water proof sealer to keep water out. Everything else is the same. Was always worried about the bottle cap being the weak link. If the bottle broke,unscrew the cap and put on another bottle.