August 2008

Cruising catamaran

Kurt Hughes designed this 37-foot cat as a "small world cruising machine." I really enjoyed reading Kurt's comments that came with this design. They are refreshing. "The design was begun for a company on the East Coast but they became underfunded," he writes. "Finishing the design was done here without funding, since it looked like a very useful design to me."

In order to really understand what this cat looks like you need to see it in a 3D model so your eye and brain can factor in the effect of the beam and how it diminishes the appearance of height and bulk. The 3D models and pics I have of the unfinished boat show it to be unusually good looking. The hulls have a lot of shape. They show a full length chine and sectional shape not dissimilar to what we saw in the SeaCart. The topsides flare in order to keep the BWL as low as possible while capturing some volume through the flare to gain interior volume. There is a lot of freeboard in the hulls but you need this if you want headroom. I think these hulls have enough interesting shape to them that they carry the freeboard fine.

The D/L is 112 if I use the loaded-to-cruise displacement. Beam max is 25 feet, 4 inches for an L/B of 1.47. Daggerboards give a board-down draft of 5 feet, 4 inches and a board-up draft of 1 foot, 8 inches. The prismatic of the hulls is .63 and they appear to be symmetrical as I see the chine detail is on the outboard and inboard side of each hull.

Cruising cats have their accommodations well defined by the different heights of the main bridgedeck between the hulls and the cabin sole in the hulls. Segueing these two areas can be a difficult design challenge. Kurt has laid out two alternative plans for this level. The main deck accommodations for the Hughes 37 feature either a galley and dinette or a galley, dinette and inside steering station. Obviously if you eliminate the inside steering you get a much nicer arrangement on this level with a big galley. With inside steering the galley suffers. Kurt has also drawn a series of alternative layouts for the hulls. You can have three double berths and two heads. The optional layouts involve the size and configuration of the heads and the addition of a bathtub in one layout. Layouts in the hulls have to work around the intrusive but necessary daggerboard trunks. Of course you could have those silly little stub keels instead of daggerboards, but then you could kiss speed to weather goodbye. There is 6 feet, 3 inches of headroom on the main deck level.

The rig is very standard and that's good. If you are going offshore you do not want an experimental rig. There is a short sprit to get a gennaker or asymmetrical chute away from the forestay. The SA/D using the loaded displacement is 17.03. I'd like to see the clew of that blade-style jib lower. I like to get the clew down close to the deck if I can.

Kurt says that all catamarans are on a continuum between "full-on racer and a houseboat," and that lately the houseboat models have been the most popular and being able to claw off of a lee shore is not as important. "I say a catamaran should be able to sail well and claw off of that lee shore in a blow. To do that, I have to make sure the cat has deep boards and good rudders. That it has enough bridge clearance and a skinny waterplane. And that it has an aerodynamic house cabin. It reminds me of when you have to give a dog a pill but he won't take it. You wrap that pill in some burger and give it to him. I see my work as kind of slipping the pill of a good-handling boat into the burger of spacious accommodation. With the nice space, they won't taste the pill of good handling."