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Old 10-30-2011
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Quote:
Originally Posted by JohnRPollard View Post
I hope this design meets the thread criteria for "Interesting Sailboats."

Test Sailing a Pacific Proa
Hi John,

Certainly it meets and nothing had been posted yet about Proas. Thanks for posting it.

By the way do you know that Proa means in Portuguese and Spanish, Bow? Those boats are probably called like that because when the Spanish or Portuguese find the first native ones they found out they had two proas and no popa (stern).

That one looks particularly interesting.

Proas did never manage to get a grip on mass production cruising boats, i don't know why, perhaps because they sail in a different way.

On this site we can find a good explanation about the differences between a Proa and a Cat, advantages and disadvantages:

Pacific Proa Advantages:

The Pacific proa gets advantages over the catamaran by using the same weight of materials (cost!) to create a significantly longer main hull with higher speed potential:

a longer hull is more easily driven for fast ocean passages and more appropriate to the scale of large seas offshore.

transferring up to 100% displacement to the single large leeward hull as the windward hull lifts results in smooth, comfortable speed with minimal wetted surface.

when pressed for maximum speed, the longer leeward hull with similar rig and no additional lateral stability (the ability to resist tipping over sideways) results in greater longitudinal stability than a catamaran. Instead of pitchpoling, the Pacific proa will roll gently onto the leeward pod .

a small, lifting hull to weather for stability is mechanically easier and lighter than connecting two hulls of equal size and weight (catamaran) or using "floats" of 100%+ buoyancy on either side (trimaran).

While modern materials and methods make structure less of an issue, the crossbeams on a Pacific proa are less stressed than a catamaran of similar displacement.

For the very same reasons, however, it is also true that the Pacific proa carries much less weight for it's length than a catamaran.


Catamaran Advantages:

The catamaran has broad flat transoms aft that carry weight well and reduce pitching; the proa is pointed at both ends.

The catamaran has extra privacy afforded by two hulls for accommodations.
Since there is only one large hull, adding length to a proa returns less accommodation volume and weight carrying capacity than the same length added to a catamaran.

The proa's main hull might be narrower than the catamaran, using a length to beam ratio of 17:1 for speed, resulting in a smaller interior space.

For these reasons, a 21 meter (69') proa has barely the same accommodations as a 43' catamaran. When compared to an 18 meter (59') catamaran, the 21 meter proa has significantly less accommodation volume...


Pacific Proa compared to Catamaran


Of course the guy is a bit partial about Proas

There are other advantages in a Cat: A substantially bigger righting moment for the same weight and beam and also a more straight forward way of changing tack, losing less time and distance.

Regards

Paulo

Last edited by PCP; 10-30-2011 at 04:19 PM.
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