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Proa talk

rob denney

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A 6m wide footprint is less likely to capsize sideways than a 4m wide one.


Happy to discuss these in detail if you want to.


I would like a detailed explaination of this. What does the 4m relate to?


I am now in a position to build and campaign a race boat, so we shall see what happens.

Yes please, and please do the proa fans a favour by waiting until you have a result before talking it up.


I have plenty of performance data, but without pictures or race results it is too easy for cynics to devalue it.

Thats like a race car manufacturer saying they have the fastest car without winning a race, very easy to devalue!

And with a bit of practice, they will shunt as quickly as an overlapping genny boat will tack.

I bet they wont, even Sundreamer would agree with me on this?

By the way, there is a 12m cruising harryproa sitting at Coffs Harbour waiting for a weather window to leave for NZ.

I actually think the cruising HarryProa is a great idea, and has a great future, im keen to have a look at this one, please keep in touch with its arrival.


I have no issue with the cruising proa, the weight, the engineering or the top speed of the HarryProa, and think the cruising version is cool. :thumbup:


I do have a problem with people bragging about how their new race boat (proa or otherwise) will win a race when they have no evidence to support it. :thumbdown:




PS something has been niggling me for a while, Does the race version have a gennaker? if not how does it go downwind against boat that have gennakers? :?:

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The answers to your boat questions are:


4m is the approximate athwartships footprint of GregW's 7.6m trimaran, assuming it is 7.6m wide. It is a factor in a sideways capsize from wave action. It is why a wide raft is more resistant to capsize than a narrow one, all else being the same.


You want another bet? Happy to oblige. Another carton of rum says I can shunt my 15m proa quicker than any single hander can tack their overlapping genoa 15m cat. A shunt and a tack being from tiller down until we are up to speed on the new tack. Any wind or sea conditions, but the rougher it is, the more I will win by. Why you keep assuming you know more about harryproas than I do when you have neither seen nor sailed one is a mystery to me, but as long as you do and want to keep boosting Mount Gay's bottom line, I will keep taking you up on it.


No extras. I hope to go downwind the same way A and C class cats and my 7,5m prototype do. An efficient small rig on a light platform vs an inefficient big rig on a heavy platform. It will only work if I can keep the weight down and the sail area up. We will see. Same as everything on my personal boats. If it doesn't work, I will change it. I am sure you have a comment on the wisdom of this approach, I look forward to hearing it.


I'm glad you like the cruising proas, surprised you can't make the connection that something 75% lighter with half as much windage will be pretty potent. Hope I can demonstrate it to you sometime.


The rest of your post is personal abuse and is irrelevant to this discussion so I have ignored it. Calling me a braggart on a boat discussion forum says a lot more about you than it does me.


I am away for a week, with dubious internet access. Feel free to continue kicking the sh#t out of me and the boats till I get back. I will try and answer any questions or comments on the boats then.





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Hi Rob,

I think you'll agree healthy discussion on any concept benefits us all, while personal attacks are simply unnecessary and harmful.

I have tried to stick to what I know from my experience to add to the discussion, not to cause offence.

I do think your concept is unique and clever. I've been aboard Blind Date in Holland and was impressed, although didn't realise the weight at the time.

I think the modern cat and tri have evolved to be very versatile craft in terms of wind conditions, perhaps most notably in the light. Having a variety of extras, although as you say, expensive, does give impressive performance. Speeds approaching 1.5 times windspeed are now common.

This is perhaps one of the areas that may be a challenge ahead for you. You can't beat sail area in the light, no matter how light the boat. But then as you say you can change that in the future.

Also power/stability is a function of beam and weight. Taken to infinity a boat that weighs nothing would have no sail carrying power. So the compromise is between being able to push hard at speed, and being light.

Perhaps also some of the comments about boat weight and strength relate to the last Coastal Classic where 85% of these conventional, but by your standards over weight and over built multihulls, failed to finish the race. To race these boats need to be strong to cope with rough coastal conditions.

In terms of selling boats some 'bling' these days is expected, including a nice paint finish. In NZ perhaps the most successful 'class' recently has been the 15m cant keel boats, all immaculately presented.

Back to topic, boats such as the F22 with a sophisticated folding system, typically fail to sell well in NZ as they are perceived to be too expensive, or complex to build.

Finally, good luck with your project, I applaud you bringing something different to sailing, and I hope we can keep these discussion technical not personal.




Tim Clissold

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Hooray, some intelligent comment.


I also worry about light airs and downwind without extras. On the Harryproa forum this has been discussed and I believe it would be easy to add a screacher , free flying on a rope luff, use a code 0 type furler, tack it to either bow and sheet off the end of the main boom with a high clew.

But would probably try without it first, could easily be added if the need was percieved.

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The answers to your boat questions are:


You want another bet? Happy to oblige. Another carton of rum says I can shunt my 15m proa quicker than any single hander can tack their overlapping genoa 15m cat. A shunt and a tack being from tiller down until we are up to speed on the new tack.


You were talking about wed night harbour races when you said the Proa will shunt as fast as a Tri will tack, This series isnt single handed its fully crewed as are almost all harbour races. Then you start sayng it will be even faster in big seas? Twisting the subject a little bit there are no seas in a harbour race?


Do you expect a 15m racing Proa faster then a 15m Racing Cat?

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Do you expect a 15m racing Proa faster then a 15m Racing Cat?



It is an absolute nonsense to compare a cat and a proa of the same length. Better to compare two of same weight or same sail area. Length is meaningless when discussing a proa.

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Another carton of rum says I can shunt my 15m proa quicker than any single hander can tack their overlapping genoa 15m cat.



It is an absolute nonsense to compare a cat and a proa of the same length. Better to compare two of same weight or same sail area. Length is meaningless when discussing a proa.


I have to admit I am confused guys?

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Not that hard, we were answering two different questions.


Can Rob shunt as fast as a normal multihull?, he thinks so, My boat wont but his is different.


Is a proa faster (sailing not shunting) than a cat? I say you need to compare like with like, same displ or sail area not length.

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this is just bullshit semantics. I'd like to compare my shitty old GBE to an RC multi outside Rangitoto in 25kts - I might stand a chance but I'd be laughed out of town!


The fact is the Rob's boat may indeed beat some boats longer, or shorter than his, in windier or windless days, with a sea swell, or not, over a straight line course or w/l, fully crewed or single handed. We all know that its very difficult to compare multis - Dan's 20+yr old 9m plywood tri beat Jon's newish (by comparison) 15m carbon cat to Russell because the conditions were perfect for him that day (oh and he's pretty damn good).


In light airs it could reasonable to compare similar length race boats as they will largely be in displ. mode. In higher breezes it may not be and perhaps righting moment kicks in (incorporates sail area or more accurately, displ. and beam - all of which significantly contribute to performance when planning). However length will still play an important factor maintaining that performance in a seaway. So while I understand Rob's argument, I don't think you can simply dismiss the argument of comparing like length boats just because the designer doesn't wish it.

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1.6 - 3.5 mms depending on location. As the loads are not uniform along or around the beams, nor is the laminate.






1.6-3.5mm's??!! jesus!!

Whats the name of the engineer that specified these beam sizes?

Whats the safety factor that is built into the design?


what will happen in a side on seaway?

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On what do you base your statement that the skin weight and paint weight are "nonsense"?


Coastal Classic Weight: Which part of the following from my earlier post is not clear?

"The weight ready to sail: 581 kgs

Safety gear for solo Transpac which I would like to do next year: 180 kgs Includes spares and nav equipment, not sure how it relates to the requirements for Cat 1 or Cat 3 in NZ, but seems close to what Mr Wolf has on his boat, so probably close

Ready to race, ex crew, food and water: 761 kgs"


Paint: Using Tim C's numbers of 1 kg of paint per sq m and assuming Timberwolf weighs 950 kgs and has surface area of 100 sq m, more than 10% of your boat's weight is bling. Costs you at least 5% of your performance, more than 30 minutes in a 10 hour Coastal Classic. This is wasted weight, money and time to me, but if it makes sense to you and Tim C I guess we just have to agree to disagree.


Weight: From my earlier post

"Surface area hull, deck and bulkheads, overlaps and tabbing 40 sq m"

"Beams 7.5m x 200mm dia tubes, including reinforcing at the hulls 18 kgs each = 36 kgs" Tabbing is the joining of bulkheads, deck and hull. Using edge radii, the joined area is lighter than the base laminate. The "reinforcing at the hulls" is what holds the beams in.


W was 10 years ago. It was, (for the third time!) completely different to what it is now and would have got Cat 3. Jason said no way. It didn't mean enough to us to make a fuss. Still doesn't, I was just setting the record straight. Apart from it winning me 10 grand in a Royal Institue of Naval Architecture (RINA) design contest 8 years ago I have had nothing to do with it since then. So could you please stop bashing me over the head with how bad it looks now?


Re your latest post. Greg did not mention the weights. Please pick holes in them. It would be a bastard if I have made a mistake and you didn't let me know just because Greg wants a tri, not a proa. And don't let all the nice people "kill your joy". I like criticism, it makes me think. But please, back it up with numbers or facts, rather than sweeping generalisations which very quickly get boring.


I will be happy if it is "fast in a straight line", but what aspects of the Coastal and the RdR won't it do well in?




Hi Rob


Thanks for the opportunity to comment.


Paint weight:


There are 4 different areas to consider:


Deck Non skid

Topsides/Gloss area

Anti fouling


Each of these areas will have a different weight of paint on them.

If you stick with proven long lasting paint systems then you will be looking at

Primer/Undercoat/Topcoat on the gloss areas.

You need at least a few coats of each to provide an adequate barrier and a long lasting paint system.

On the antifoul areas you need primer and antifoul, the weight per square metre of antifoul is far higher than your 200 gm/sqm.

Interior: If you choose not to paint this once the inside laminate gets wet it will actually take on weight due to the porosity of the infused panel. (Assuming you put shiny side out).


You need a certain level of finish to attract potential buyers to your boats. Just rolling a couple of coats of undercoat on (which is all you can do if you stick to the paint weight you have given) will not look very professional and will put a lot of people off.


Paint weight on Timberwolf:

I used 16l of Durepox, 32 l of Interprotect, 8 l of YRA600, 6l of Reaction Lacquer, 6l of Awlcraft 2000 and 8l of Micron 66.

This includes Hull, Decks, Interior, Foils and Spars.

In weight terms (allowing for overspray that is 60 kg)

Pretty realistic but still a very light system, I did not put the minimum recommended thicknesses on at that weight as it is a race boat, but I still expect the paint to last over 5 years.

The surface area of the boat is about 85 m^2 (so I'd allow about 700 gms per m^2 as a light system).


Panel weight:

As TimC pointed out your panel weight is a very light laminate that will ding up very easy. That leads to additional weight in fairing etc.

But stating a panel weight is a "nonsense" because on a small boat like yours there are so many joins at corners, bulkheads etc.

The stated 40kg may also be a little optimistic.

You also need to allow for CoreBonding, joins in the core, as well as the weight of coves etc.


Coastal weight:

No, its all quite clear.

But you need a motor and some gas, plus a crew, their gear, water, food etc.

How about dock lines and such like.

A couple of Anchors, chain , rode etc.

the original statement was it would be 700 kg.

Clearly by your own admission that is not the case,

And so what it will still be extremely light.



I know a bit about this, and an average of a 2.5mm wall on a boat this wide?

Yes I checked it is stiff enough to do the job, but it is a long way from a safety factor of 4 strength wise.

So in my view it is miles undercooked for an ocean racing vessell.

Based on my quick calcs this would not get cat 3 based on beam strength alone.



This would not get cat 3 based on Freeboard requirements or Accomodation requirements.

At the end of the day you need to get a Cat3 certificate for it before you raise issues about being refused acceptance to a race.


Re: Fast in a straight line:

Been covered by others, am suggesting you need Downwind sails for light air etc.


Good luck with your project

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Do you expect a 15m racing Proa faster then a 15m Racing Cat?


In some, possibly many, cases, Absolutly. Reference my earlier post. 42mls odd in 2 hours. Knot to shabby for a tree trunk and stuff stolen from a building site, literally, so imagine what one built of Gucci materials could do.


Yes they have some downsides like every boat but when up and going these proa things can be seriously fast by anyone standards and that's being said by an ex 18fter sailor.


Around a olympic course?? Don't know to be honest but I wouldn't be betting against the proa. A reaching up to the BOI in the CC? I'd have my money on the proa before a Cat.


I'd still probably build a Cat before a Proa though.


Maybe they were so quick because they didn't paint them ;) :)

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so how much do you reckon we could buy that old shitter of a proa for thats down at westhaven..... (or would anyone notice if we just borrowed it for a few weeks....)


we can do some designed experiments to conclude once and for all....'


experiment one....sail it on a wednesday night as a proa and see how we get on.... then the fun starts....


same rig, but we convert it to a cat !!! and race again.....


hmmmmm but we might have to make the cat shorter just for a fair comparison...(yeah I dont get this bit either).....

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Wolfie, I just read the whole book on safety regs ( now I know why people don't bother racing to Noumea), couldn't find anything on freeboard, can you point me towards what you were referring to? Thanks.

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Squids right - there's nothing on freeboard, Harddrive used to have cat3 and if she can get it then the w CAT could. TWU sailed coastal a few years ago despite only sailing a couple of races since rebuild and breaking which was pretty expected as it had broken in it's couple of warm up races too.


However I'm a little perplexed about robs comments regarding Jason. I'm not sure when "w" was built but I took over the leadership of the NZMYC in 2001 for the coastal 2001 race and the coastal chairmanship for the 2002 race. There is no way Jason made those comments while I was there or since.


The only time I have seen W sailing in a decent wind was about 5 years ago and it did a big V and ended up on chelthenam beach. Looking at it, I can see no reason why it would not get cat3 with a few add ons and if it did there is no way in hell the NZMYC would ban it. Why would you? Where's the risk, it carries a dinghy and it's not gonna sink

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However I'm a little perplexed about robs comments regarding Jason.


I am too. I was going to ask him tomorrow. I think the most likely explanation was a misunderstanding, Jason meaning he thought it would never get cat 3 (without a cabin) therefore saying it would be banned from the race (rightly so just like a skiff or windsurfer) and Rob misunderstanding his comments as saying it was banned completly?


I would have thought given the circumstances Rob has described, an owner would have gone ahead and got cat 3, then if banned from the race done it as an unofficial entry, won (assuming it was fast enough), then used the publicity generated to protest the banning in the first place?


Has this "W" ever finished a race? or even started one? is the rumour I have heard about the owners/designers talking it up while it was being built saying it was going to beat all the local boats true? Is it true it broke in Half?

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Squid said: You will probably find that you'll get the same accom. as you would in a small tri in a longer/faster/more seaworthy proa for the same price.


I responded: I think I'll get away a little cheaper (7.6m ply tri) but, rigs aside, there wouldn't be much in it.


Built with comparable materials, on a per kilo basis, the lighter boat should be cheaper to build the structure of. Based on the weights published by Rob (thats 550kg sailing weight for a 10.5 x 5.25 Harrigami), any 25’ ply tri is going to be heavier, but ply/epoxy is cheaper than strip timber/epoxy of the prototype I based my original observation on. So while one is heavier the construction method is cheaper. I’ve heard that foam/polyester is around the same price as ply/epoxy, so on that basis the lighter HP should be cheaper to build. I’m sure the neighbours would get used to the styrene.


The weight of either boat is actually irrelevant. What is relevant is what comes out of the builder’s pocket. To repeat, for me, that’s 5.5KNZ so far to buy materials for the hulls and beams finished but not painted. Thats using BS1088 Meranti, Malaysian kauri and WEST. It could be cheaper with lower grade materials. I think I should have the boat painted and assembled for 9 to 10k and ready to rig. My own rough costing brings a strip plank Harrigami using the same quality of materials in at NZ10.6k to the same stage. I did say there wouldn’t be much in it. Certainly not enough for price to be a consideration in picking one or the other.



Squid: In a storm longer/wider is always going to be better, do I have to explain that?

No what I would like you to explain is whether there is any difference, due to the short hull on one side, between the way a harryproa behaves in rough weather and a catamaran of the same length. If you look at the harrigami photo below you can see there is very little displacement in the ends of the long hull. I can’t see how the extra length (meaning the 1.25 metres from the bows back) of such a hull contributes much towards seakindliness when its tied to a short hull on the other side of the boat.


The telescoping mast is a new idea, yet to be tested. I like new ideas.

Telescopic top masts were used on Americas cup boats back in the early 1900s http://www.americascup.com/en/acclopaed ... ntent=1743

It is good that Rob is re-visiting the idea.


Is fora the plural of forum? Maybe fori? guess it depends on whether it is greek or latin, better than forums.

It is a plural of forum. The other is forums, I like fora better too.


I think Greg made the right choice of boat with the tri.

It was the interior layout that clinched it. Comfortable, if close, accomodation for 2, with room for 4 or 5 people to sit around in the cabin and have a drink and a yarn if desired, without having to be wedged into bunk shelves or down tunnels.

Also I do not consider myself prejudiced against proas. I made an informed decision some time back that they weren't a type of multihull that appealed to me in the LOA size range I'm interested in owning.


Rob: You queried the weight of the beams, I told you how I arrived at it and why I thought it was correct. Hard to do this without mentioning engineering.

No I did not. Perhaps you could show me where I did. I think you have confused me with one of the other posters.



Rob: Storm comparison is a bit tricky without knowing anything about your boat,...

My boat is (or more correctly will be) 7.6 x 6m. But a comparison between it and an HP is not what I was getting at. I posted this somewhat in jest to squid “Also while you have one longer hull in a Harryproa you also have one short one. Is one side of the boat therefore less seaworthy than the other? ”, but I guess it underpins what I'm getting at. I’m asking whether, in the context of seaworthiness, the long hull/short hull configuration of the HP has some disadvantages in comparison with a similar sized cat with two equal length hulls. See above for more details.

Harrigami on trailer.jpg

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Reference to Freeboard is that a Cat3 Inspector must firstly assess the overall seaworthiness of a vessell before completing the Cat3 inspection.

A comparison to Harddrive or TWU is totally different. W has less than half the freeboard of the other two. A couple of years back waves were lapping over the side of W into its cockpitty thingy, and as the self drainers were underwater it was starting to sink. That is at its marina in a very sheltered location.

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Is it true it broke in Half?



No Sammin it didn't break in half, as Phil said we were watching it wobbling along from Sundreamer and the rig fell over sideways tearing the whole rotation tube etc out with it and literally carving one of the hulls in half. Luckily for them it happened just off Cheltenham beach.

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