Many years ago you could not find a sailboat without a boom gallows. A boom gallows is usually a piece of nice teak that is made into a board about the width of the cockpit of a sailboat. The board has cups or indents across the top that allow a boom, when not in use with the mainsail, to cradle in the cups. Hence the name, boom gallows, as it looks very much like the gallows of old when the heads of people were placed in the gallows for punishment!
Why would you want to have a boom gallows? Good seamanship requires a boat to have a place where a wildly rolling and flailing boom can sit tight and not move. Today topping lifts, tightened mainsheets, and solid boom vangs have seemed to have taken the place of the sturdy and safe to use boom gallows.
When you are hoisting a sail, or lowering a sail, good seamanship requires you capture and control the boom. By putting the heavy sail laden boom in the gallows, you eliminate the problem of a madly-swaying dangerous boom. Even when at anchor or at a marina the booms on most sailboats today rely on a really tight mainsheet opposing the tight topping lift, and still the boom has movement and can rock back and forth in a destructive, jerking motion.
If you ever are in conditions that require a trysail instead of your mainsail, then it is almost mandatory to control your boom that is now not being used by the mainsail. If you do not have a boom gallows to secure it, you will have a potential raging boom that could be very dangerous in rough sea conditions.
A boom gallows also makes an excellent hand-hold, whether aft or forward of the cockpit. It’s a secure place to lean against when taking sextant sights, and it is another strong attachment place for jack lines.
We even used ours as a place to stow a rolled up cockpit cover.
If you ‘Google‘ Boom Gallows, you will be amazed at how many styles, placements, and designs there are out there for you to see and copy.
Seriously, I would not go to sea without a boom gallows.