A Wharram Pahi under sail
There’s a saying that wind will capsize a cat but waves will capsize a tri. Anything will capsize a mono but it will come back up again or else sink to the bottom of the ocean. The other two will sit upside down and rest.
Ye takes yer choices. In making a final choice of design – that is before getting into the fine detail to the nearest sixteenth of an inch – I was going back and forth between the cat and the tri, not wishing to clamp lead to the bottom and wanting to be able to near-beach the boat in the shallows.
Constant thoughts in mind were steep, seven metre seas and gale force squalls out of nowhere, e.g. coming down off a mountain. Keep coming back to the Pahi type above but with the pitching taking out, i.e. less rocker [the curve at the bottom].
Undersides not unlike this but chined
Anyway, all things considered, from price to seaworthiness, I’ll go for the cat and here are some of the required elements:
1. 31 ft LOA plus LWL, 20ft beam [15ft centre-to-centre], each hull 5ft beam at the gunwhales and 4ft at the WL. Double-chine for strength [see pic below] and ease of building, using epoxied 3/8th ply, maybe Douglas fir. Double-ended a la Archer.
2. Only slight rocker but suggestion of sheer through scalloped bows and sterns [see Pahis and the pic below], slightest of tumblehome [for the leeboards, see top maroon strip in the pic below], cabin roofs fall away to the centre of the boat.
3. Four beams, each 6ft 2in apart, strapped down. This creates three large compartments in each hull, each discrete and separated by walls, with inward facing hatches for access.
Undersides also not unlike this
4. Thought long and hard about rudders and finally went for kick-ups, as with the leeboards. Reason was that when a gust is abeam, the hulls need to slide sideways. Underslung rudders require skegs and fairing into a shallow keel. Can’t have it both ways with cats.
5. Port hull [bow to stern]: Front cone, bulkhead with crumple struts, compartment for folding bike, 1st beam [for mast], head [with stand up shower] and vanity unit, 2nd beam, cabin 1, 3rd beam [for mast], cockpit [standing room], 4th beam, water storage, sealed bulkhead, aft buffer cone.
6. Stbd hull [bow to stern]: Front cone, bulkhead with crumple struts, compartment for folding bike, 1st beam [for mast], galley, 2nd beam, cabin 2, 3rd beam [for mast], cockpit [standing room], 4th beam, water storage, sealed bulkhead, aft buffer cone.
Dipping lug for’ard and standing lug aft
7. Deck area: Aft of 1st beam – three boxes across for storm sail, anchor, sea anchor [all neatly away], behind that the ship’s dinghy crossways, suspended half above and below deck on seatbelt webbing for lowering, then decking.
8. Aft of 2nd beam – living deck [planking] but traveller hawse across near rear for Main 1. Aft of 3rd beam – deck [planking], then two boxes port and stbd, clear of tiller, for drogue and tools.
9. Two masts, each 23ft and 21ft, bowsprit and bumpkin, four sails – yankee, jib, main, mizzen.
Two balance lugsails
10. Estimated speed: upwind maybe 8 knots with leeboard, beam reach maybe 14 knots, downwind not a lot less, cruising 10-12 knots [who needs more?].
11. This craft is not meant to go about easily – it was designed to track, not to be able to pivot. To go about, it would have to be sailed about and foremain kept backwinded until around. Small price to pay.