One feature of an HP not yet mentioned on this thread, but previously noted, is the reduction in heeling moment when the lw is pressed. This is unlike other multihulls where the base of the rig lifts when the mast is in the middle of the two hulls and the lw hull is loaded and the ww hull unloaded. 

An HP performs reasonably well in light wind.  Neither hull makes substantial wave drag at low speed making hull cleanliness the key factor in light wind performance.  In the wind range where the shorter, heavier ww hull starts to make waves it is already reducing displacement and the displacement of the longer slender lw hull is increasing.  The lw hull has low wave drag throughout its range of displacement and speed range.

A distinct benefit of a HP over a tri is the clear deck space..  At times the trailing end of the boom on the Aerorig can be difficult to get at if some thing near the main clew needs attention.  However this would not be so much of an issue with the schooner rig where the sails can be worked independently.

The bi-directional hull is not the most efficient form for planing.  So any boat with the power-to-weight to plane is going to be more efficient if unidirectional.  The amas of modern tris are typically long slender planning hulls with near full width transom and little rocker aft.   Even the maxi monos are now designed as planing hulls with wet transoms at rest.

For berthing and trailering the HP takes up less space than a tri of similar accommodation and performance.  

In my view a tri or cat makes more sense as a foiling platform than a HP.  However that may be because I am yet to see a foiling HP.

Rick

On 1 Mar 2019, at 9:05 am, Björn bjornmail@gmail.com [harryproa] <harryproa@yahoogroups.com.au> wrote:

I like all the aspects of the Harryproa except one thing - that it has two hulls in the water in light airs. (Maybe also that it has to stop to gybe.)

Why not instead build a trimaran with unstayed rig(s), one centerboard and one rudder?

With basically just one hull in the water in light airs, it will always have less wetted surface than two hulls, unless it's way heavier than the HP. It will have the same amount of appendages(foils in the water) as the hp. It will have a rig which is as easy to control.

From my point of view, it's only in two situations a multihull feels slow:

-When the wind is really light

-If it glides a lot sideways (leeway) when sailing into the wind.

This is from sailing Hobie 14 and Dart 18 for a couple of summers. (Both are without center boards.)

I suspect that a well designed trimaran might not be that much heavier than a HP. Maybe the design will have to have short floats attached with a single beam to accomplish that. And then maybe small lifting foils on the floats, which starts lifting when the float gets loaded enough to have higher drag than the foils.

Maybe you can tell that I'm a fan of the extremely cool boats made by Gary Baigent, which I've seen on boatdesign.com and sailinganarchy.com =)

(And the French hydrofoils which is part of his inspiration. =))

/Björn