Peruvian proa

 
aerohydro
 
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aerohydro
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12 November 2013 22:08
 

Hello All,

Here’s a proa design that I’ve stumbled across.  Designed by Derek Kelsall - a British yacht designer, now based in New Zealand - this 16 meter long proa is being constructed by a Peruvian-based yacht builder. It has a biplane rig. Here are some links:

    Kelsall 16m proa - 3D views

    Kelsall 16m proa - construction photos

    Kelsall 16m proa - plans (1800 pixels wide)

The website doesn’t appear to have been updated since 2011, so I’m not sure what the current status of the proa build is.

I have to say the design perplexes me somewhat. The sailboat appears to have its weight evenly distributed across the waka and the ama. If that’s the case, then what’s the benefit of using the proa configuration? Wouldn’t making it an asymmetrical catamaran be a better fit?

Cheers,
Paul

[ Edited: 13 November 2013 13:12 by aerohydro]
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KSS-16mProa-3.jpg
KSS-16mProa-plan.jpg
 
 
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Editor
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12 November 2013 22:35
 

I am equally perplexed. This appears to be a proa that would do better as a cat.

 
 
Rob Zabukovec
 
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Rob Zabukovec
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12 November 2013 23:11
 

An excellent example of that infamous phrase: “dysfunctional catamaran”

 
old greg
 
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old greg
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13 November 2013 06:18
 

It seems to me very much like something Rob Denny would design, which makes sense given his association with Derek Kelsall.  Perhaps when Kelsall was teaching Denny about KSS, Denny was teaching Kelsall his own particular proa philosophy.

 
TINK
 
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TINK
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15 November 2013 12:19
 

How on earth do you raise, lower and reef the sails in seaman like way with that canopy in the way, confused. Not a craft I would want to take to sea

Tink

 
 
CapnRon
 
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CapnRon
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21 November 2013 09:42
 

Hi Ron here. 

I have been a member of the forum for a while and confess to be a long time lurker.  Love the discussion on the forum.  Thanks for the interest in our Seabbatical Drua.  Please don’t blame Derek too much for this one, as it took a bit of convincing to get him interested in the project but I think he is excited about it now.  But then again maybe not as I know he put way more effort into it than he originally thought it would take and I am very grateful for his commitment.

My goal is to build a modern Fijian Drua.  I think this platform has many advantages, and I think the Polynesians knew it also.  I view it as a hybrid between a catamaran and a proa.  My goal is to get a little bit further down the cost / accommodation / performance spiral where normally you only get two of the three.  For those that are not sure what a Drua is there is some information on line.  Here is one link http://sailingforsustainability.org/page/drua-kalia-alia.

The numbers look encouraging.  The material list is 80% of Derek’s 39 ft cat with a modular build.  If the cost and final weight are on budget then it should be a very large, affordable, fast, fun boat.  We are combining a few novel ideas, (most of which have been demonstrated before) but do expect there will be some further development of the concept.

All lines will be lead to the helm but there will be easy access to the solid coach roof if a batten fouls a lazy jack.  This has to be an improvement over our Leopard 45 cat where you could net even stand on the bimini, or had to balance on the targa arch to service the back of the boom.

I look forward to your continued input.

Cap’n Ron

 
aerohydro
 
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aerohydro
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21 November 2013 22:38
 

Hello Ron,

Many thanks for post. Really pleased that you have detailed the Seabbatical Drua. Can you explain why you went with the biplane rig configuration and not, say, a schooner rig?

Best of luck with the build!

      Longtermcharters.com - Seabbatical Drua 55

Cheers,
Paul

 
CapnRon
 
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CapnRon
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22 November 2013 11:48
 

Hi Paul,

My thinking is that the goal is to get the WW hull moving after a shunt to the point where the rudders and boards can take over.  Both the schooner and biplane have the center of effort aft.  So moving sail area to WW helps this situation.  However, slowly sheeting in the forward sail of the pacific schooner has the force vector more forward than leeward still causing the boat to round up until it is fully sheeted in.  The other thing I didn’t like about the pacific schooner rig is the forward sail should be sheeted in more than the aft one for balance,  yet this makes the aft sail less effective than normal.  A schooner that can tack also means a free standing rig which is bigger, or may be more expensive and has high loads at the hull.

We are going with a biplane rig with a strut at the hounds. The WW sail is smaller and rotates 360 degrees under the strut the LW sail is 60% of the total sail area rotating 260 degrees.  Keeping the LW sail sheeted perpendicular to the hull, with the WW sail not sheeted should keep the boat parked.  Sheeting in the WW sail first should get the boat moving again independent of CLR with little risk of rounding up.  This means there should be no rush to complete the shunt.  We may add a light weather head sail later.

Dick Newick convinced me to pursue a design that could tack as well as shunt.  He felt that shunting only was a limitation to safe entry into some anchorages.  I do like the advantage of being able to tack onto the slower, short hull to LW tack for short distances or confined areas, and to shunt when on longer passages.

Thanks for your interest

Ron

 

 
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Skip
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22 November 2013 14:43
 

CapnRon,

Thanks for posting your thinking on what is an out of the ordinary project compared to some of our more “conventional” craft <G>.

I agree wholeheartedly that being able to short tack a shunter has intrinsic value, I’ve done it both accidentally and on purpose. The accidents didn’t hurt and the on purpose solved a dock approach that would have been a real mess any other way.

cheers,
Skip

 
aerohydro
 
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aerohydro
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23 November 2013 17:45
 
CapnRon - 22 November 2013 11:48 AM

Dick Newick convinced me to pursue a design that could tack as well as shunt.  He felt that shunting only was a limitation to safe entry into some anchorages.  I do like the advantage of being able to tack onto the slower, short hull to LW tack for short distances or confined areas, and to shunt when on longer passages.

Thanks for the explanation.  Most insightful!  Fully agree with the need to tack as well as shunt.  Having that versatility in a design, even if it’s only used sparingly, is a good thing.

Cheers,
Paul

 
CapnRon
 
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CapnRon
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25 November 2013 15:40
 

I find it fascinating that by the time of Captain Cooks second and third voyage of discovery the Drua had displaced almost all of the catamarans and they were considered technically inferior to the Drua.  I assumed it was because they were having a hard time trying to find logs of the same length.  These boats were plank built to over 100 ft in length and were the fastest voyaging canoes built to date.  Mostly reserved for war ships and carrying well over 100 people each. 

It is an interesting read for anyone spending time thinking about the history of sailing multihulls.  Makes you wonder why this form vs just larger pacific proa’s or catamarans?

Ron

 
alexander
 
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alexander
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26 November 2013 12:45
 

I am disappointed.
We are interested in boats that are unusual. I heard a lot of “unfriendly” comments when I built or sailed my boats, people were laughing about “Gavial” and “Kleinnixe” in Switzerland and “Nixe” in Thailand because they did not know proas and they could not imagine that a such different layout could work. That is normal.

Now I read comments in this thread about Derek Kelsall and Rob Denney that surprise me in a negative way. They both proved already many times that their concepts work. Maybe someone does not like the style, but THEY WORK.
So please be nice and let them try.
And wait and see.
Then you will know and maybe you learned something.

Alex

 
 
old greg
 
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old greg
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26 November 2013 15:29
 
alexander - 26 November 2013 12:45 PM

Now I read comments in this thread about Derek Kelsall and Rob Denney that surprise me in a negative way.

Seeing as I am the only person in this thread who mentioned Rob Denney and, other than the OP, also the only person who mentioned Derek Kelsall, I can’t help but feel that this comment was directed toward me.  I take offense at this as I said absolutely nothing negative about either man or any of their boats.

 
Bill S.
 
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Bill S.
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26 November 2013 20:39
 

All:

As far as I know this is a unique forum in that there are far less ad hominem attacks here than just about anywhere in the Internet.  Mr. Schacht actively moderates and quickly gets folks to tolerantly fit in or face expulsion.

I understand how someone like Alexander could be quite sensitive to negative feedback on his brilliant execution of his designs.  I’ve had similar responses from anyone I’ve talked to about my proa concepts - people are willing to quickly judge without taking the time to understand fully the design’s merits.

I’ve noticed is that some new people accustomed to more combative forums tend to bring a more aggressive attitude with them.  This quickly changes as they begin to understand how things work here.  Mr. Denney is very passionate about defending and promoting his Harryproa designs - but this Proafile site promotes more objectivity and acceptance of differing approaches than most.

Nothing helps me more than having a wide variety of designs to review - I would hate to have anyone leave here.


Bill

 
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26 November 2013 21:38
 

Bill, you cut me to the quick. I have a tendency to jump to conclusions and I should just shut my damn mouth sometimes. Cap’n Ron and I don’t exactly see eye to eye on proas, but that doesn’t mean he shouldn’t march to the beat of a different drummer, and good on him for doing so. One of the things that bugged me about the “other” forum was this tendency to push others into well defined camps of opinion, you are either with us or against us, that sort of thing. As if there wasn’t room for many different takes on the same basic theme.

This doesn’t mean we can’t be constructively critical, far from it, but there is a line between criticism and dogmatism that I hope we don’t cross here.

Old Greg: Don’t take offense. It’s just that we’re working through a lot of baggage from the previous forum. I took no offense from your post.

 
 
TINK
 
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TINK
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27 November 2013 11:24
 

Looking back I think my post of the 15th November is pretty offensive for which I apologise. Must have been a tough day and I could have tempered my language a great deal. I have posted some plain bonkers ideas which people have be kind enough to ignore or give constructive criticism.

So sorry again and let’s keep better proa forum creatative and positive

Tink