Just notes in no particular order:

Cats are faster but like tris, bury the lee bow. Tris have better secondary stability but weight of cruising cat compensates.

Why double masted? Jibs are useless for single-handed, downwind and in a breeze, especially as spinnakers are a pain, one-up.

Forward mast won’t hobbyhorse because a] underwater shape is buoyant forward b] mast small anyway – only 16’. 98sqft isn’t going to dive the nose on a 23’ boat.

Skeg drift. Have to have shoal keel on the river – weed, branches etc.; can’t sail closehauled anyway with the gaff rig.

Gaff rig for tight to broad reaching, which is the only place to be for a cruiser. Low aspect not a disadvantage here. Double main [main and foresail] incrementally reefable for exact wind conditions.

Why 23’? Any longer requires taller rig, more than one man can handle. 98sq’ and 145sq’ are the outer limits, so this determines length, beam and mast height. 19’ mainmast for ease of carrying [wing adds weight].

Mast is 9” wing – fine in gaff configuration. Luff and shaped gaff on battcars for instant reefing and raising and rotator below boom.

Wishbone tripod boom heavier but rigidity more important here – in a blow, it will flex enough, plus sail will be reefed, plus wbb accepts the reefed sail better and no need for cords flying about.

Underwater shape a compromise cat/mono. Too much rocker to plane and slight V retained for shoal keel. Ratio WL still 12.5 to1.

Internal weight minimal – cross grids for two foam mattresses, semi-portable primus galley, run off drain for toilet [no smelly heads]. This is an overnighter, max two nights.

2’9” clearance under beam more than enough on a cat. Dry ride. Removable bimini struts. Three beams and 3’3” hull breadth on 14’ overall beam strong enough, given this rig.

550lbs will still move with that sail area.

4’Hx 3’Wx7’L enough inside hull for 1.7 person berth.

Decks slanted down inwards, cushioned hatches. Cockpit 6” above WL and wouldn’t matter anyway – open stern. Cat heel gives better protection from wind and spray.

Angled window on two poles front of cockpit neat idea from Orange – lies horizontally when not in use. Loss of speed but who cares when the face is protected and the lee window is always horizontal?