Sunday, August 25, 2013

How to tie on a bolt snap

How to properly tie a bolt snap for scuba diving.

primary hose with attached bolt snap
Attaching a bolt snap to your gear is something most divers need to do from time to time, whether it is to a back-up light or to a pressure gauge, and if you are a DIR diver you'll be attaching a lot of them.  Here is a breakdown of how to do it correctly.

When tying a snap on we use #24 braided nylon cave line.  Nylon line is durable,  lasts an incredibly long time, is cheap to replace, and odds are you will always have some on hand to do so.

To attach a bolt snap, the only knots we will really be tying is a simple reef, or square knot.  and a "half knot".

For demonstration here, I'll use a larger diameter rope to attach a bolt snap to a wooden dowel.  step one is to loop your line through the bolt snap three times.  No knots yet, we are just winding the line around the dowel and through the snap.

step 1step 1step 1

step 2Next we will tie two knots to secure the bolt snap in place.  The first will be a half knot.  You will want to put some tension on the line to tighten the loop you made around the dowel.  While keeping the tension, tie the half knot.

Step 3 is to tie the final reef knot on the opposite side of the bolt snap.  you will need to pull the ends of your line under the bottom of the snap and the loops holding it to the dowel.

step 3step 3

Pull the ends of your line to ensure everything is snug and seated where you want it, then finish your reef knot.

step 3step 3

With your knot in place, the last step is to cut the excess line and melt the knot with a lighter.  Nylon is essentially made of plastic, and melts easily.  Doing so ensures the knot will never loosen or fray.

Here is the finished product on my primary hose.

attached botlt snap

Armed with this knowledge you can now put a snap anywhere you need.  For some advice on what types of bolt snaps to use, check my post on bolt snap selection.  Good luck, and dive safe.


  1. Great article. Very nicely done with the photos, better than some comparable articles I've seen online.