This all depends upon the wave length/period its direction and your encounter frequency. Since it is appreciable to all boats. It would just occur at a different wave/period/heading etc from a harry to a cat for example, that is all. Thus what are the predominate waves in your locale, you wish to sail...and then compare. Thus try one!
But all poor motions can easily be mitigated by changing direction and/or speed and is applicable to every boat.
Of course, except that changing course for comfort is not always desirable when sailing to windward. Assuming the waves are coming from roughly the same direction as the wind (~45 degrees off the bow when sailing to windward), the harryproa motion is less corkscrewy than the catamaran. When you sail a harryproa upwind in waves, it is very noticable. Aided, I suspect, by locating the crew in the middle of the ww hull rather than aft in the middle of the boat.
Dennis,
The added wetted surface, torque on the beams, weight and added unusable space all mitigate against a longer windward hull. Therefore, we start with the suitable B:L ratio, payload and hull weight and make the hull a suitable length. I guess for enough weight, this could mean equal length hulls, but the very low cost of lengthening the lee hull and the benefits from this means that equal length hulls on a shunting boat are not the most efficient way to proceed.
Comparing cats and proas is fraught. eg, the Visionnary Cruiser has 2 double berths, 2 singles, weighs 3 tonnes, 77 sq m sail area and large usable deck space. Maybe a 35' cat for accommodation, weight and build time. Maybe a 40'ter for sail area. And a 50'ter for length. Rank your parameters and choose which suits them best. eg, I doubt any of the above would cruise at wind speed as effortlessly under main and jib as the Visionnary does.
And the new Cruiser 60
http://harryproa.com/?page_id=1177 has 50% more sail area, is a little heavier and has a better layout so should sail even faster, while taking half the hours to build.
For given space, the cat will be heavier as it has the extra half hull, the mast supported in space with highly loaded attachments to the 4 corners and 4 water foils, plus their cases/strengthening. Obviously, some/all of these can be altered, but the more you do so, the closer you get to a harry. I know this as it is the path along which harrys were developed.
The weight differences between the harry and the weight to lee (the only thing they have in common with Pacific proas is low righting moment) types is caused by the following:
The higher the load imposed on a hull, the stronger and heavier it needs to be. A stayed rig imparts high loads to a larger surface than an unstayed one which imparts high loads to a small area.
A loaded hull with lots of cutouts (hatches, cockpits, pod, etc) needs more strengthening. The higher the load on the hull, the more strengthening required.
A stayed rig requires high bows for foredeck work, so the hull will be bigger.
The beams have to be designed for the worst case. In the harry this is normal sailing, where the beams have to lift ~60% of the boat weight. In the weight to lee, worst case is caught aback, when the beams have to lift ~80%. Consequently, the beams are heavier, maybe the mast as well. The exceptions to this case are if the little hull is so small that the boat capsizes the wrong way, or the mast falls down.
In hull rudders (weight to lee proas) need cases and considerable beefing up of the hull to withstand grounding loads. On hull rudders (harry) need neither. Small rudders (weight to lee type) need daggerboards, which are another case and more beefing up. The large kick up rudders on harrys mean no daggerboard is required.
The weight difference is exacerbated when the breeze gets up enough for the Pac type to pump water ballast.
The bigger the proa, the less these differences matter. But up to about 70' the harry is lighter. And more comfortable.
Again, these can be designed out, but the result is the same as for the cat. You end up with a harry.
There are also some major differences in handling and comfort related to small windward hulls. By small, I mean hulls which are designed for a particular load, then have more weight added, such as ballast. These are fine when the hull is loaded/flying, but in the lulls is draggy. Which is why the Pacific Islanders used easily movable human ballast, rather than supplies, rocks or water.
Intelligent Infusion is how all one offs will eventually be built. No reason it couldn't be used for cats, especially plywood ones.
