So why do mariners take shortcuts, such as using something other than correctly sized cotter pins to secure single-nut towing shackles (typically, welding rods)?
The reason is usually ignorance (“This is the way we’ve always done it!") or it’s a conscious and expedient choice made by mariners because cotter pins can sometimes be a pain in the neck to remove quickly.
So why are cotter pins so hard to remove quickly sometimes? The reason is often a lack of proper tools and/or the knowledge of how to use the tools correctly.
If the right tools are on hand when needed then deck crews can easily take apart a towing shackle and do it with minimal risk of injury. To accomplish this, I recommend putting together a tool box or duffel bag that contains, at a minimum, a pin bender (a 6"-8" length of 3/8"-1/2" nipple with a t-fitting on one end for a handle); two or more pairs of vise-grip locking pliers (needle nose and regular); a 2- or 3-lb. hand sledge; a 3/8"-dia., kenter-link breakdown tool (from Blue Ocean Tackle); and a pair of 18" bolt cutters.
Quality bolt cutters are indispensable. Usually you can simply straighten out the ends of a cotter pin using the pin-bender tool. But occasionally they get so twisted up that they cannot be removed the normal way. When this occurs, you simply cut the eye off with the bolt cutters and pull it out forwards. If it’s still jammed tight then you use a hand sledge against the back of the kenter-link tool (a modified hand sledge with a pin punch) to drive it out and avoid smashing fingers.
Crews that know how and when to use these tools work quickly and confidently. They know they’re ready to deal with any situation and can quickly adapt when they are thrown a curve ball. Adaptability is a valuable trait in the art of tugboating.