All designs are good designs... for their intended purposes.  You can carry more weight, at non-racing speeds, in a boat with two equal hulls.

  I was a big fan for Cat2fold and the Radical Bay 800 for a while, but could never quite warm up to them enough to consider a build or purchase because of the narrow bunks (and the cost...).  Also, I'd rather go with a schooner if I'm going to have two sails because they aren't likely to shadow or blanket one another unless you try to head straight upwind, in which case no sail will work, whereas a biplane rig is going to be non-optimal on some reaches.

  At one point I was ready to make the leap to a Wharram, and started building a 26' plywood dory as practice.  The dory has been on pause for a very, very long time because we built a house that took up all build/futz time, and while I may finish the dory this year, a Wharram is no longer part of my plans. 

  Early on I liked the designs, liked the ease of working with plywood in terms of repairs and modifications, and was smitten by both the traditional lines and the simplicity.  But now I see all those lashings, the four shrouds to each mast, all those failure points, and the wailing and gnashing of teeth that trailering would require, and I can't get on board.  The proa may be high-tech, but it's a lot simpler.  Plus it has all the advantages of a WTW proa.

---

  Anyway, why asymmetrical hulls?

  Many bullet points, some of which you might care about, some not, in no particular order:

    - Trailerable full-size bunks.  You can have queen-sized bunks on a trailerable boat, that folds on the water, with true queens or doubles.  (You need one narrow hull and one wide hull to do this, and/or a design where the ww hull extends over the lw hull while folded, like Gardiner's ConTrarry or the evolved Air 40).

    - Less weight.  You're not carrying around that extra hull material, and can use the savings either for the cabin structure and/or for weight savings.

    - Optimized weight.  The lw hull takes all the main sailing loads, so it has to be beefy.  But the ww hull has far less stress on it.  It's not stress-free, but it's also in a completely different class than a biplane cat, trimaran, or pacific proa.  So now X tons of glass and epoxy is going to be used more efficiently, allowing the boat to be lighter since the ww hull won't need the extra strength.

    - Less build time and cost.  Not building 15 feet of hull is a savings.

    - More speed, at speed.  The long, slender lw hull is going to be doing all the work, and will be noticeably longer for a boat of the same displacement.  The ww hull is going to be partially or mostly lifted out of the water, making its length less of an issue.  Note: this doesn't work if you want to carry a lot of people and stores, which I understand was a reason for going with your cat designs in the first place.  But if you can keep the weight down, the design should be fast, with the length going to where it's needed most.

    - Less corkscrewing.  A lightweight cat can really corkscrew after seas go past four feet because the windward bow hits the waves long before the leeward bow.  Heavy boats care less, but since we're shooting for minimal weight, this is something to ponder.  The shorter ww hull on the proa means both bows meeting the waves at about the same time, making the boat's motion much more friendly.  Less stress on both the boat and the crew.

    - Proa stuff.   If the comparison is to a cat with a mast in one null, the there's all the advantages (and disadvantages) of a bidirectional boat.  Weather to your back instead of your face, ability to stop, depower, and even reverse, on any point of sail, shunting instead of tacking in both light and heavy winds, and so forth.

---

  Of course, all that works well for my goals.  I want the fastest, lightest, most-seakindly, safest, trailerable boat, with full-sized bunks, for the least money. 

  "Safest" should probably come first, because I'd be happy to spend pages talking about why the proa is the boat I want if I'm out of sight of land, and/or sailing with crew who aren't sailing athletes.  But I can't list it first because a requirement, not a desire. 

  I lust after a fast trailerable trimaran, but I'm not willing to make that leap because of its downsides.  The proa is a boat I can desire just as much, but then also live with because of the risk factors it designs away.  It's like a fun motorcycle that won't kill you, if once could indeed make such a thing.

  If I wanted to carry the maximum payload for a given hull length, and didn't really care about hauling the boat out each year on a trailer, then the Woods or Wharram designs might make more sense.

        - Mike

StoneTool owly@ttc-cmc.net [harryproa] wrote on 2/28/2019 12:39 PM:

 

    When I was in school, it was said that the only stupid question was the one that you didn't ask, and I was always the one who asked the questions other children were embarrassed or afraid to ask. 

    This may have been asked here before.... If so please forgive my re-asking it.   What is the rationale behind having two unequal length hulls on an HP.   This is a signature feature of Rob's designs, as is the cabin in one hull, and the Aerorig, and the multiple rudders, all for obvious reasons.    The reason for the long slender hull under the mast(s) is not so obvious to me.

            I can close my eyes and conjure up an image of a "TikiProa", with one or two free standing masts in one hull of a wharram, and a cabin  on the opposite hull that extends out over the bridge deck, and the "Dennyrudders".     I know of no catamaran of any kind that has a single mast in one hull, nor have I heard anybody make a case for why it would not work.    I've toyed with the option of having a mast in only one hull on a catamaran, versus a biplane rig or central mast (all free standing).   

    At first glance the photo below looks like the mast is in the near hull (stbd) and unstayed..... it clearly is neither.   The sterns have less freeboard than the bows, but that's a trivial issue.  It isn't much of a stretch of the imagination to turn this into a "tiki proa".   

                                                                                                                                H.W.