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Old 21-05-2015, 14:35   #166
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Re: extending the saloon

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Originally Posted by ZULU40 View Post
your problem is you never quantified the drag of wire or rod rigging. So check this out
the aero drag exceeds that of water drag. Given this boat has drag reduction strategies in place
Im thinking more attention needs to be given to aero drag/sail efficiency

'I' think thats conclusive

Article Dogstar 50



yes I agree that as it stands they are expensive, if thats your biggest gripe Im pretty sure there are thing that could be done about that, it would just be heavier, perhaps 20-30% or so.
Now translate those drag numbers into actual speeds at various wind speeds and directions which is what people care about. Reducing drag only matters in terms of how much extra speed you can get.
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Old 21-05-2015, 15:52   #167
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Re: extending the saloon

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Now translate those drag numbers into actual speeds at various wind speeds and directions which is what people care about. Reducing drag only matters in terms of how much extra speed you can get.
If you are looking for cheap thrills entertainment I would suggest you do just that.

In an unlikely prospect that we can see that all else will be equal between 2 prospective craft, and given we dont have any drag polars to play with.

But let me answer by asking you, do you seriously expect that a boat with everything else being equal, except having less aero drag and on a longer hull is going to be slower? make less miles per day? ride less comfortably?
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Old 21-05-2015, 16:03   #168
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Re: extending the saloon

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Nothing about a mono requires two masts
Id take issue with that, and by example xompare the sea keeping capacity the mid size Freedom ketches compared to a Nonsuch 36. Never heard of a Nonsuch doing a circumnavigation, yet all manner of Freedom hulls including the 28's have managed that.

Quote:
Originally Posted by valhalla360
and there is nothing show so far suggesting the proa has any special benefits that allow for a smaller rig if it's still supposed to be high performance.
less aero drag and on a longer hull, what are your expectations?

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Old 21-05-2015, 17:01   #169
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Re: extending the saloon

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Originally Posted by valhalla360 View Post
Of course that bury comes at the expense of interior and is a big part of why you don't see them in cruising boats.

Of course, with no price provided so far...hmmm...I suspect when all is done and said, that price isn't going to be a selling point.

Nothing about a mono requires two masts and there is nothing show so far suggesting the proa has any special benefits that allow for a smaller rig if it's still supposed to be high performance.
Of course, with no price provided so far...hmmm...I suspect when all is done and said, that price isn't going to be a selling point.

Price is always a selling point. Even the guy buying a rolex looks for a deal. Whether you are able to make it your primary selling point is other thing but its seems to have been defined as a mission statement so I suspect it to be high up the pecking order as one of the attractions for this boat.

Nothing about a mono requires two masts

If a mono favours bendy masts it usually has two(some of those factual's u like below)

there is nothing show so far suggesting the proa has any special benefits that allow for a smaller rig if it's still supposed to be high performance.

What is performance? You need to define your index of measure then your question has a better chance to be answered.

It performs very well in the cool category I know that. If you want to know how fast it will go then we will have to wait and find out. However what it does not have is also important and a big clue to performance. It does not have a stayed mast with nasty triangular sails that have that thing called induced drag. If you look the free standing sail it is the shape of a proper wing. Triangles are ok once you get supersonic but I think the ambition is a little less here.

The advantages are going to come from the hulls and the weight or lack of it I imagine. I think it allows for a head sail but I don't know how that works here. Do head sails work with a sagging luff? I don't really know. Its not going to be a slow coach though you can count on that.




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Old 21-05-2015, 17:29   #170
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Re: extending the saloon

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Originally Posted by ZULU40 View Post
If you are looking for cheap thrills entertainment I would suggest you do just that.

In an unlikely prospect that we can see that all else will be equal between 2 prospective craft, and given we dont have any drag polars to play with.

But let me answer by asking you, do you seriously expect that a boat with everything else being equal, except having less aero drag and on a longer hull is going to be slower? make less miles per day? ride less comfortably?
Faulty logic, no one said an unstayed mast was slower (all else being equal).

That is far different from my point, that any speed gain would be so marginal as to be irrelevant. If for a given set of condition, the stayed mast boat does 7.00kts and the unstayed mast does 7.01kts, yes the unstayed mast is technically faster but you would be hard pressed to measure the difference.

Hence the question about how your numbers translate to actual boat speed which is what everyone cares about.

To move from the 60-100mph speeds to 200-500mph speeds, airplanes require tremendous amounts of additional power (orders of magnatude higher). It was far more efficent to make the plane more aerodynamic than keep throwing power at the problem.

With a sailboat doing 5-10kts, you are far from the point where you need drastically more aerodynamic rigs to achieve a given speed.
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Old 21-05-2015, 17:35   #171
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Re: extending the saloon

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Originally Posted by paulanthony View Post
Of course, with no price provided so far...hmmm...I suspect when all is done and said, that price isn't going to be a selling point.

Price is always a selling point. Even the guy buying a rolex looks for a deal. Whether you are able to make it your primary selling point is other thing but its seems to have been defined as a mission statement so I suspect it to be high up the pecking order as one of the attractions for this boat. The original post implied that it would be an inexpensive boat for the size and performance but so far no pricing has come out. They guy buying a rolex looks for a deal as you say. If the store refuses to give the price until he commits to the sale, he most likely isn't getting a good deal.

Nothing about a mono requires two masts

If a mono favours bendy masts it usually has two(some of those factual's u like below)

So you are doing a round the world in the little day boat? The other appears to be a one off.

there is nothing show so far suggesting the proa has any special benefits that allow for a smaller rig if it's still supposed to be high performance.

What is performance? You need to define your index of measure then your question has a better chance to be answered.That seems to be a moving target for the proponents of this boat. Sometimes its small and cheap, other times it's high performance, depends on the point they are trying to make.

It performs very well in the cool category I know that. If you want to know how fast it will go then we will have to wait and find out. However what it does not have is also important and a big clue to performance. It does not have a stayed mast with nasty triangular sails that have that thing called induced drag. If you look the free standing sail it is the shape of a proper wing. Triangles are ok once you get supersonic but I think the ambition is a little less here. If we are waiting to see, they don't get credit for being faster, cheaper and have more accomodations until we get the actual price and speed data.

The advantages are going to come from the hulls and the weight or lack of it I imagine. I think it allows for a head sail but I don't know how that works here. Do head sails work with a sagging luff? I don't really know. Its not going to be a slow coach though you can count on that. How do we know what we can count on? Other than vague statements of speedy, there is no data to back it up. Compared to a catamaran with a similar design brief and a stayed mast, I would put my money on the cat winning any races.




......
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Old 21-05-2015, 18:09   #172
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Re: extending the saloon

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Originally Posted by valhalla360 View Post
......
I have seen references to prices but I don't want to bounce them because its not my place to do so.

But from what I have seen if you are looking at 35 foot cats then also seriously look at this. If you are seriously interested I am sure the price will be made available to you.

Speed.. There is reference to another boat from the same family that is in my opinion hitting 15 knots. I saw reference also that the speed was reported by a reporter. We have to trust a little but I can't imagine the pictures are simply free hand concept images. There will be function in that form that has projected polars. The proof will be in the eating but regardless of performance it is a well thought out package.

Those two boat pics I posed were from a google search that serp'd many. I just gave reference to two.

We Just have to wait Valhalla. It is normal when launching a new product to have what is called beta customers. Price, if it is going to be one of the USP's is not going to given out just so the competition can make use of it. Public price positioning will be available soon enough but at this point you are reading mission statements.
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Old 21-05-2015, 21:09   #173
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Re: New style Harryproa cruiser

Cost of the Proa built by Ballotta will come back to material cost and hours in the build and I can understand Ballotta fixing a price until they know actual hours needed for the build.

I do know labour costs are lower than many countries ( approx $12/hr) .

There is a section on Ballotta's website with some build prices. Suspect it could be similar or less than the Kelsall 39 listed.

cheers
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Old 21-05-2015, 22:35   #174
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Re: extending the saloon

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Originally Posted by valhalla360 View Post
Faulty logic, no one said an unstayed mast was slower (all else being equal).

That is far different from my point, that any speed gain would be so marginal as to be irrelevant. If for a given set of condition, the stayed mast boat does 7.00kts and the unstayed mast does 7.01kts, yes the unstayed mast is technically faster but you would be hard pressed to measure the difference.

Hence the question about how your numbers translate to actual boat speed which is what everyone cares about.

To move from the 60-100mph speeds to 200-500mph speeds, airplanes require tremendous amounts of additional power (orders of magnatude higher). It was far more efficent to make the plane more aerodynamic than keep throwing power at the problem.

With a sailboat doing 5-10kts, you are far from the point where you need drastically more aerodynamic rigs to achieve a given speed.
actually its more complex than that
I had a look around before I wrote what I thought, and I quipped ' lbs of boat per $' which is a deliberate statement about why I find this boat interesting. And I looked at some videos and I watched her accelerate while shunting but could hardly believe my eyes.

when you talk about power I had a different equation in mind, like what speed does a boat do per sq ft of area, and the subsequent effect that has on the boats ability to remain right side up. And at the end of the day what is that to cost me. Theres an alluring formula extension there.

I suspect Denney is not for nothing being coy about his numbers. Ive had the benefit of sitting on this particular fenceline before with stakes a few billion A$ taller than this and its a game I understand very well but I see he has a lot going on here with this boat. And Im not about to wreck his party by speaking unwisely, for his benefit and possibly for mine.
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Old 22-05-2015, 03:28   #175
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Re: extending the saloon

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Originally Posted by valhalla360 View Post
The proa design is basically forced into an unstayed mast if you want it over the downwind hull because if you ever got back winded, there would be nothing to support it. It's a design compromise to accomodate a limitation of the proa.
I had condensed some additional thoughts so...
Elsewhere there has been a fierce discussion about self righting multihulls, we need to look at this machine in several parts.

Firstly, the effect on the capacity to be blown over due to gusts and high winds assisted by the layout of the sailplan, lowering the centre of effort. These are conventional measures common to monohulls.

Secondly, the layout of the hulls, where unlike a trimaran the larger ama is more resistant to sticking into a wave, stalling, crashing, and pitchpoling. As it is still an ama its beam/length ratio is more conducive to speed, likewise its greater length adds to boatspeed and with a smoother more comfortable ride. If caught aback it has the volume of the main hull to fight off the capsize force due to its buoyancy.

Thirdly, the spars unlike alloy masts are composite CF and therefore hollow. In themselves they will be a righting force because they are also buoyant. Indeed it has been used as a system for preventing capsize beyond 90 degrees even by monos. To further right the boat the booms are winched outboard until the boat falls back over.

Thus a compendium of features align, parts more than the whole. It is quite a thing... quite the nicer of the proa layouts, and I think superior to the trimaran and in some ways the catamaran.
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Old 22-05-2015, 04:52   #176
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Re: New style Harryproa cruiser

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Originally Posted by downunder View Post
Cost of the Proa built by Ballotta will come back to material cost and hours in the build and I can understand Ballotta fixing a price until they know actual hours needed for the build.

I do know labour costs are lower than many countries ( approx $12/hr) .

There is a section on Ballotta's website with some build prices. Suspect it could be similar or less than the Kelsall 39 listed.

cheers
Building in a lower cost country, certainly will cut costs but you get the same benefits regardless of boat design. This is not a benefit of a proa design but of the local labor costs.

There are exceptions but usually there is still a correlation between the skill and the price of labor.
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Old 22-05-2015, 05:04   #177
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Re: extending the saloon

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Originally Posted by ZULU40 View Post
I had condensed some additional thoughts so...
Elsewhere there has been a fierce discussion about self righting multihulls, we need to look at this machine in several parts.

Firstly, the effect on the capacity to be blown over due to gusts and high winds assisted by the layout of the sailplan, lowering the centre of effort. These are conventional measures common to monohulls. So it's effectively has the sail plan of a reefed standard rig.

Secondly, the layout of the hulls, where unlike a trimaran the larger ama is more resistant to sticking into a wave, stalling, crashing, and pitchpoling. As it is still an ama its beam/length ratio is more conducive to speed, likewise its greater length adds to boatspeed and with a smoother more comfortable ride. If caught aback it has the volume of the main hull to fight off the capsize force due to its buoyancy. True the ama won't be the speed limiting part of the design. It's the main hull that will limit speed. No one has provided any evidence, it won't be speed limited by the shorter fatter hull. Unlike a 40' cat built on 60' hulls where both provide the higher speed of 60' hulls. (If you argue 40' hulls don't limit speed, you are arguing that a 40' cat will keep up with a 60' cat)

Thirdly, the spars unlike alloy masts are composite CF and therefore hollow. In themselves they will be a righting force because they are also buoyant. Indeed it has been used as a system for preventing capsize beyond 90 degrees even by monos. To further right the boat the booms are winched outboard until the boat falls back over. So all wiring and rigging are exterior to the mast and it is completely sealed against water intrusion? Maybe I need a picture because when lying on it's side, winching the boom outboard will have it sticking straight up or straight down providing no righting moment.

Thus a compendium of features align, parts more than the whole. It is quite a thing... quite the nicer of the proa layouts, and I think superior to the trimaran and in some ways the catamaran.
I will agree it has a lot of the limitations of a trimaran with some odd quirks. The smaller ones are great for a weekend speed demon (If I ever get around to finishing it, I am building a proa dingy). Larger ones have very limited accommodations for the size.

With a similar design brief (high speed and minimal accommodations compared to overall size), I have to disagree that the proa will be superior to a cat.
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Old 22-05-2015, 05:18   #178
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Re: extending the saloon

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Originally Posted by ZULU40 View Post
I had condensed some additional thoughts so...
Elsewhere there has been a fierce discussion about self righting multihulls, we need to look at this machine in several parts.

Firstly, the effect on the capacity to be blown over due to gusts and high winds assisted by the layout of the sailplan, lowering the centre of effort. These are conventional measures common to monohulls. So it's effectively has the sail plan of a reefed standard rig.

Secondly, the layout of the hulls, where unlike a trimaran the larger ama is more resistant to sticking into a wave, stalling, crashing, and pitchpoling. As it is still an ama its beam/length ratio is more conducive to speed, likewise its greater length adds to boatspeed and with a smoother more comfortable ride. If caught aback it has the volume of the main hull to fight off the capsize force due to its buoyancy. True the ama won't be the speed limiting part of the design. It's the main hull that will limit speed. No one has provided any evidence, it won't be speed limited by the shorter fatter hull. Unlike a 40' cat built on 60' hulls where both provide the higher speed of 60' hulls. (If you argue 40' hulls don't limit speed, you are arguing that a 40' cat will keep up with a 60' cat)

Thirdly, the spars unlike alloy masts are composite CF and therefore hollow. In themselves they will be a righting force because they are also buoyant. Indeed it has been used as a system for preventing capsize beyond 90 degrees even by monos. To further right the boat the booms are winched outboard until the boat falls back over. So all wiring and rigging are exterior to the mast and it is completely sealed against water intrusion? Maybe I need a picture because when lying on it's side, winching the boom outboard will have it sticking straight up or straight down providing no righting moment.

Thus a compendium of features align, parts more than the whole. It is quite a thing... quite the nicer of the proa layouts, and I think superior to the trimaran and in some ways the catamaran.
I will agree it has a lot of the limitations of a trimaran with some odd quirks. The smaller ones are great for a weekend speed demon (If I ever get around to finishing it, I am building a proa dingy). Larger ones have very limited accommodations for the size.

With a similar design brief (high speed and minimal accommodations compared to overall size), I have to disagree that the proa will be superior to a cat.
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Old 22-05-2015, 07:25   #179
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Re: extending the saloon

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Originally Posted by valhalla360 View Post
So it's effectively has the sail plan of a reefed standard rig.


its a lower centre of effort (CE) of the sail area establishes a higher margin of safety with the ability to better balance the CE/CLR relationship or more easily manage sails or completely feather them.

The proa can use a drag reduced unstayed system, a cat cant easily do that,
certainly not on the same weight

Quote:
Originally Posted by valhalla360
True the ama won't be the speed limiting part of the design. It's the main hull that will limit speed. No one has provided any evidence, it won't be speed limited by the shorter fatter hull. Unlike a 40' cat built on 60' hulls where both provide the higher speed of 60' hulls. (If you argue 40' hulls don't limit speed, you are arguing that a 40' cat will keep up with a 60' cat)


Remember the main hull already has the profile of the cat hull so it is not drag deficient to a cat hull. The ama is longer and less resistant than the cats lee hull.

The drag sum further favours the proa.

Quote:
Originally Posted by valhalla360
So all wiring and rigging are exterior to the mast and it is completely sealed against water intrusion? Maybe I need a picture because when lying on it's side, winching the boom outboard will have it sticking straight up or straight down providing no righting moment.
mast buoyancy prevented boat going all the way over



buoyant boom is hauled out to right the boat


Quote:
Originally Posted by valhalla360
I will agree it has a lot of the limitations of a trimaran with some odd quirks. The smaller ones are great for a weekend speed demon (If I ever get around to finishing it, I am building a proa dingy). Larger ones have very limited accommodations for the size.
many a trimaran has gone over due to its smaller ama digging into a wave, stalling the boat. Unspent inertia will overturn the boat into a pitchpole. A longer larger ama that the proa has is what is required. Two such ama's on a tri would be ridiculously wasteful.

Tris have a lot less usable volume and are less safe and stable.

Quote:
Originally Posted by valhalla360
With a similar design brief (high speed and minimal accommodations compared to overall size), I have to disagree that the proa will be superior to a cat.

I think it is likely the proa has less accommodation than a cat so if accommodation is your priority
....... you need a bigger proa

  • The proa can use a drag reduced unstayed system, a cat cant easily do that, certainly not on the same weight
  • a proa will be smoother and more comfortable
  • The drag sum favours the proa.
  • Tris have a lot less usable volume and are less safe and stable.

any way you cut it, area for area, pound for pound,
a proa is going to be faster, more stable more comfortable
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Old 22-05-2015, 08:24   #180
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Re: New style Harryproa cruiser

Compared to a traditional production catamaran, you are correct, but the premise earlier was you provide the same accomodations but stretch the 40' cat to 60'.

That negates most of your points and would have a similar cost to the proa as extending narrow hulls requires negligible labor and materials, so cost should be similar.

Also you "photo" appears to be a computer generated image of a small beach proa, so I'm still not buying that the mast will keep her from rolling or that you can swing out the boom and it will flip upright.
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