A freediving neck weight is commonly used by freedivers who dive competitively on lines or in the pool. It allows the diver to adjust weighting precisely and put the weight at a point on their body where the weight acts like a rudder pulling instead of pushing the diver. It changes the center of buoyancy behind the diver giving you easier straighter dives.
Materials
Bicycle Tube
Get a bike tube that is wide enough to accommodate the amount of lead you want to put in the tube. It's better if the tube is slightly too big than too small. The tube can be new or used. New ones should last a bit longer and are relatively inexpensive.
If you're going to wear the weight around your neck you'll probably need a wider tube than if you are going to wear the weight around your waist. Tubes in the 1 1/8" - 1 1/4" are a good start. You can make multiple weights from one tube. if you want to make a neck weight that can hold more than 3-4 lbs you're going to want a larger diameter tube of 1.75"+.
Lead Shot
The best place to get lead shot is from bag weights. Ideally you can upcycle some old ones with holes in them. If not you can get some online.
Plastic Clip
A plastic clip allows you to easily put on and remove the weight from your neck. A 1" or larger size clip is pretty good. If you're making a bigger heavier weight you can go with a larger clip like this.
Tape
Tape protects the bike tube and makes the whole thing tighter and looks better. You can use electrical tape of varying colors or hockey tape which comes in colors like yellow, red, green, pink, or blue.
Combine colors of electrical tape to make for a flashy design.
Steps to build a freediving neck weight
Step 1 - Cut bike tire and fill with Shot
Cut through the tube with scissors and cut it again far enough away so that you will have enough material to go around your neck or intended body part. Be sure to check for punctures if it's a used tube before cutting. Also exclude the stem from the section. When it's full of shot it will need more material and you'll be able to cut it shorter later so make it extra too long.
Now thread one end of the tube through the clip and put some tape on it to secure it into place. Fill the tube with shot. If you know how much weight you want, weigh the shot first before filling the tube, otherwise fill it up until you think it looks good. Take the shot filled tube and wrap it around your neck to see if it's approximately the right length. Adjust the shot level until you're satisfied with the amount.
Step 2 - Close it up
Place the other side of the clip on the end of the tube. Fold the tube over and tape it in place. You can then re-check to make sure it's long enough you fit round your neck comfortably. When it feels good cut the tube so there's just enough extra material to go through the clip and past it by 1.5 inches or 4cm.
Step 3 - Wrap it up
Use the duct tape to start wrapping the end of the tube where it threads through the clip. This is important to wrap it tight but not too tight because the tape will stretch. Overlap the tape as you wrap around the tube going from one clip to the other.
Feel free to cut it tape and use another tape along the way to make multiple colors. It's best to do a minimum of 2 layers of tape to help protect the innertube from punctures.
Step 4 - Dive!
About the Author
Byron Kay is a freediving instructor and the founder of Kona Freedivers and owner of Kona Honu Divers as well as Kona Snorkel Trips. They stand out as Hawaii's top rated and most reviewed businesses among their peers having a perfect 5 star rating on google. To learn more about Byron and his latest goings on visit his bio page.