We are often asked why Juno is not rigged with a spreet like most of the old Thames trading barges.
We couldn’t rig Juno with a spreet because of the need for a sheet horse, which could not be fitted because of the position it would have to cross the cockpit (which has seating for ten and the wheel / steering pedestal). The boom therefore enables the mainsail to be sheeted to the bridge deck (which runs athwartships between cockpit and companionway), from a point on the boom about 6ft forward of the mainsail clew. The boom has a large sheave set in to the aft end for the clew outhaul (which is then lead forward to a snubbing winch and cleat mounted on the side of the boom). The tack down haul is simply a handy billy from the tack to a cleat on the aft face of the mainmast tabernacle.
During the later years of Thames trading barges, quite a few of these vessels were rigged with a boom and standing gaff (as JUNO has). These barges were known as ‘Boomies’ and considered to be better suited to reefing in heavy weather, although the boom was sometimes a bit of a hinderance when loading and unloading cargo.