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Old 08-05-2016, 22:46   #31
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Re: New Harryproa 40F Design Appears

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Originally Posted by ZULU40 View Post
back in post #22 you said
"The 40F proa has less than 1/3 of the accommodations of a typical 40' cat."

If you are comfortable with your own opinions, clearly the cost comparison is in the positive
Sure, if you accept a stripped down boat with very minimalist accommodations compared to a comfortable boat, length for length, it's cheaper (proa or cat).

When to compare apples to apples, is where the cost comparison falls down. If you load the proa up with what the market considers reasonable accommodations, the proa will be much slower and much more expensive. If you strip down the cat to be extremely minimalistic, the cat will be much cheaper and much faster.

I think I've made my point. If I'm wrong and on an apples to apples basis, proas are better, I expect we will see them displacing the catamaran market...I'm not holding my breath. So feel free to proceed with this discussion without me as no one has been able to provide apple to apples evidence that they outperform catamarans with similar design goals.
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Old 08-05-2016, 23:08   #32
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Re: New Harryproa 40F Design Appears

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Originally Posted by valhalla360 View Post
I'm not talking about taking an existing boat and grafting 5' onto either end. I'm talking about at the start of the design process leaving the accommodations and other features as it but extending the hulls and otherwise leaving the boat as if it was a 30' cat.

The extra hull is just a few gallons of resin and some fiberglass. Labor while laying up the hull is negligible (at most a couple of hours)...so on a production boat we are looking at maybe $1-2k on a $250k boat. That's less than 1%.
Just not realistic nor how it works in practise.. Strange that any production cats of 40ft cost lots more than a 1% more than similar 30ft cats. Not talking owner designers/builders here.
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Old 08-05-2016, 23:15   #33
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Re: New Harryproa 40F Design Appears

I'm sorry, but I just can't get past the idea of shunting to sail a boat.

Am I wrong, or does every change of course that brings the wing angle across the centerline of the boat require coming to a stop?
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Old 09-05-2016, 03:51   #34
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Re: New Harryproa 40F Design Appears

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Just not realistic nor how it works in practise.. Strange that any production cats of 40ft cost lots more than a 1% more than similar 30ft cats. Not talking owner designers/builders here.
That's because no one does what we are talking about (extend the hulls but don't increase the accommodations) because they won't sell. If people buy a 40' boat, they want the accommodations of a 40' boat...regardless of people telling them how much interior space they should accept.

Shuttleworth sort of took on this idea but they complicated it (not sure if it ever got beyond concept drawings). They had bow and stern hull sections that would fold up when docked but lower into place to increase the hull length when sailing. I believe the goal was to balance slip/haulout fees while getting the performance of long narrow hulls. The hinge system has it's own set of issue though.
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Old 09-05-2016, 03:55   #35
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Re: New Harryproa 40F Design Appears

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I'm sorry, but I just can't get past the idea of shunting to sail a boat.

Am I wrong, or does every change of course that brings the wing angle across the centerline of the boat require coming to a stop?
That is exactly how shunting works.

For racing it would certainly be a complication...though I'm not sure, you might be able to take advantage of it by messing with who has right of way when your tack changes without the traditional boats realizing.

For cruising, it's rare to short tack, so not really a big concern. On the positive side, you should never have to worry about getting caught in irons.
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Old 09-05-2016, 04:41   #36
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Re: New Harryproa 40F Design Appears

Hi Rob, one question, can your proas short tack at all? Or is shunting so efortless that there is never any need to.

My Brother has a 30 foot proa, and certainly down here in Tassie with the sudden windshifts and a few narrow channels he would love to be able to sail on the wrong tack occasionally to sneak out of a bay, or if caught aback by a gust.

Cheers
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Old 09-05-2016, 05:09   #37
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Re: New Harryproa 40F Design Appears

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Originally Posted by valhalla360 View Post
Sure, if you accept a stripped down boat with very minimalist accommodations compared to a comfortable boat, length for length, it's cheaper (proa or cat).
you would still be facing poorer beam to length, ie additional unused wetted surface on such a stripped down cat.

Quote:
Originally Posted by valhalla360
When to compare apples to apples, is where the cost comparison falls down. If you load the proa up with what the market considers reasonable accommodations, the proa will be much slower and much more expensive. If you strip down the cat to be extremely minimalistic, the cat will be much cheaper and much faster.
somehow you think this is as you say 'apples to apples'. Well the bad news is you wont ever be right.

A proa provides hulls in the region of 1/11th beam to length in the accommodation hull and 1/20th beam to length in the longer leeward hull that wouldnt give a cat any accommodation at all.

A proa allows a much greater righting arm, can therefore carry a larger rig on the same righting arm, and without the burden of rig stays and associated rigging that rig can easily be more aerodynamic freestanding because it has the asset of mast bury in the leeward hull. One cannot achieve this in the middle of a cat because the weight involved in supporting a freestanding rig makes it nonviable.

A proa quite naturally makes use of its longer leeward hull which will provide more speed, better seakeeping and a smoother ride that a 30ft cat could ever be imagined to do.

That leeward hull takes less materials, less manhours to construct, costs less money than the half catamaran it replaces

and somehow these differences are not apparent to you because as you say you can simply get to work with a few gallons of resin and a few hours labour to produce a 40ft cat from a 30ft cat

dude, even Walt Disney couldnt make that happen in Fantasyland

Quote:
Originally Posted by valhalla360
I think I've made my point. If I'm wrong and on an apples to apples basis, proas are better, I expect we will see them displacing the catamaran market...I'm not holding my breath. So feel free to proceed with this discussion without me as no one has been able to provide apple to apples evidence that they outperform catamarans with similar design goals.
well fat chance of that right?
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Old 09-05-2016, 21:11   #38
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Re: New Harryproa 40F Design Appears

Quote:
Originally Posted by valhalla360 View Post
That's because no one does what we are talking about (extend the hulls but don't increase the accommodations) because they won't sell. If people buy a 40' boat, they want the accommodations of a 40' boat...regardless of people telling them how much interior space they should accept.

Shuttleworth sort of took on this idea but they complicated it (not sure if it ever got beyond concept drawings). They had bow and stern hull sections that would fold up when docked but lower into place to increase the hull length when sailing. I believe the goal was to balance slip/haulout fees while getting the performance of long narrow hulls. The hinge system has it's own set of issue though.
Which is exactly what I am saying. as you indicate Shuttleworth may have thought about it but it never happened. As you and I have said no one does it.
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Old 10-05-2016, 08:25   #39
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Re: New Harryproa 40F Design Appears

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Originally Posted by valhalla360 View Post
...

Shuttleworth sort of took on this idea but they complicated it (not sure if it ever got beyond concept drawings). They had bow and stern hull sections that would fold up when docked but lower into place to increase the hull length when sailing. I believe the goal was to balance slip/haulout fees while getting the performance of long narrow hulls. The hinge system has it's own set of issue though.
Quote:
Originally Posted by downunder View Post
Which is exactly what I am saying. as you indicate Shuttleworth may have thought about it but it never happened. As you and I have said no one does it.
Denney shows how to do in a 40' (oops 30') folding proa
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Old 14-05-2016, 05:18   #40
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Re: New Harryproa 40F Design Appears

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I'm sorry, but I just can't get past the idea of shunting to sail a boat.

Am I wrong, or does every change of course that brings the wing angle across the centerline of the boat require coming to a stop?
Yes. Shunting is a little slower than tacking, considerably slower than gybing. It is safer and less stressful than either as the breeze and waves build. There is never a need to back the jib, steer in reverse or pick a calm spot to tack. There is no wild surfing down waves while you try to pull in the main, followed by it crashing across and into the shrouds when you gybe and never any need to granny gybe. But the biggest advantages are 1) you do not need to sail over canvassed so that you have enough power to tack. You put up enough sail to be comfortable, knowing that the boat will always be under full control. 2) In a man overboard situation, you can reverse the boat in seconds, sail straight back to the MOB and stop, all under complete control. Obviously does not work like this if he fell overboard while sailing downwind, but getting back upwind in the proa would be a lot quicker than in a cat, especially if the cat had a spinnaker or screecher up.

Snowpetrel
You can short tack, but once you have sailed a properly set up proa, you don't see the point. This from an observer: " I watched Rob shunt his 7.5m/25' proa upwind up the narrow (30m/100' for some of it) boat filled channel in front of his house so fast and easy I thought he must've had an electric motor hidden in the leeward hull. I would've had a very difficult time doing it in a beach cat without stalling, hitting somebody's boat and/or breaking out a canoe paddle. With the exception of a wind surfer, I had never seen a sailboat with a reverse gear before. He could head right for something, then throw it in reverse, back away and bolt off in a new direction under perfect control."

Val,
Your post #29 is mostly irrelevant. The 40F client wanted a boat with all of his requirements, not a list of boats that fit some of them. He describes the 40F as the cleverest boat design available. This may or may not be correct, but fast, light, low cost boats and happy clients are why I design boats.

Re: "He did not want the cost, weight and hassle of extras, or any sails that could jam in extremis and require him to leave the helm to fix them."
This refers to headsails, extras and furling systems. He did not want to be wrestling wet sails on the foredeck in a squall in the middle of the night. Hence rigs that lie quietly when the sheet is released, and that can be raised, reefed or lowered singlehanded regardless of wind strength or direction.

Re: Until comparable examples are provided, the burden of supporting the claim that this design is cheaper is on the one making the claim.

A Maine Cat 30 costs $US230,000 and weighs 2 tons. The 40F weighs less than a ton and should cost between half and 2/3rds as much. The 40F has better performance numbers, more usable space and fits in a mono slip.
The Maine cat 41 weighs 5.5 tons and costs over half a million. The 50' harryproa I mentioned in post 19 cost and weighs a little more than half this. In this video it is travelling effortlessly at wind speed. There are no videos or reports of the cat saling at windspeed under main and headsail, or any indication from the specs that it would, so the harryproa would appear to be a better performer. This boat was the first of it's kind. Later ones have better rudders, sharper bows and are far easier to build.

These comparisons are between one off builds and production boats. If the cats were one offs as well, the difference would be much larger.

If you think the video is not "apples to apples evidence that harryproas outperform catamarans with similar design goals." please explain why not.

Re "just extending the bows".
You have it the wrong way round. The majority of cat owners and designers would be happy to add "1-2 thousand dollars" to the build price to increase their boat's length and performance by up to 25% (ie a 40'ters accommodation on 50' hulls) and pay the increased marina fees that went with it. Most of them would jump at the chance to pay more than this for smaller performance gains. Why aren't these catamarans available?

1) the resultant narrower hulls do not have enough room.
2) the extension adds enough weight that an increase in sail area is required, which requires an increase in beam, so you end up with everything getting larger.
3) the boat will look different and most owners do not like to step outside what is currently seen as normal.

1 and 2 are not a problem with extending the narrow, low lee hull of a harryproa, which is why they work so well. 3 is slowly changing in regards to harryproas.
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Old 14-05-2016, 05:47   #41
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Re: New Harryproa 40F Design Appears

I always wish people would post photos in these threads.
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Old 14-05-2016, 05:57   #42
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Re: New Harryproa 40F Design Appears

Folded.
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Old 14-05-2016, 05:58   #43
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Re: New Harryproa 40F Design Appears

Deck.
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Old 14-05-2016, 05:59   #44
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Re: New Harryproa 40F Design Appears

Cutaway.
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Old 14-05-2016, 06:00   #45
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Re: New Harryproa 40F Design Appears

Overall.
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