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Old 16-03-2008, 11:10   #31
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Ditto!

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Why is it when somebody sticks his head out to accomplish something that is not done before, that others try to chop it of as fast as possible.
Give these people a break and the benefit of the doubt, otherwise we would still be sailing in the wooden boats designed 500 years ago with an average speed of 2 knots
A Quote by RICK:

Quote:
Man was not put on the moon and successully retreived without technology
which many sailboat people still condemn as being something that "if it
hasn't failed it will" which is a fallacy flying in the face of
successful facts. By repeating such defeatist anti-technology drivel
such people are merely ensconcing themselves in caves amidst a world of
wonderful opportunity. Don't deny others with such defeatism who might
otherwise benefit from the bigger picture.
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Old 18-03-2008, 03:16   #32
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Rob

I’ve checked out your site – it took me a little time to get used to the design but the more I thought about it the more I liked it. The 50’ seems to sail very fast (15 knots at 15 knots wind speed on the YouTube video) and added safety of the design are both strong selling points – as is the construction cost.

I’ve a few issues:

The payload seems low (3,808 lbs) – particularly once outboard, fuel, water, batteries, solar panels, nav. gear are added in. After that there’s the weight of the crew to add in plus personal items.

The saloon and interior seems tight – particularly for live-aboard / long-cruises.

Perhaps my concerns are misplaced – the saloon diagram I find a little difficult to visualise. My simple brain works better with planar views. Would modifications / additions be required for cold climate sailing; e.g., building materials, heating etc.?

You mentioned (above) that you’ve a 60’ design and I wonder to what extent the living space and payload issues are resolved in this new design?

The conversion to electricity seems a good idea but I wonder if you’ve had time to consider the weight impacts? Gideon also seems to have designed a useful wind-generator mounted on top of the main – could this be incorporated in to your design?

Finally, the construction issue is playing on my mind. Ideally I’d prefer the designer to do the build and put in the electrics, tanks, pumps, nav. equipment etc. at the same time. I believe you offer such a service. Without specifics you’ll not be able to provide an estimate of costs but perhaps you could advise on the standard construction costs for the 50’ and 60’ designs?

(After that I’d need to think of how to get the boat to Ireland – but taking a year off work may provide an attractive solution …)

Thanks – and the best of luck in taking this forward!
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Old 18-03-2008, 10:23   #33
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Rob

I know you've not had a chance to think about my last post but I just entered some of your figures to calculate speed potential, SA/D and the motion comfort ratio. I believe I've the formulae correct but I'm not at all sure how they should be adjusted to reflect the asymmetry. Your design just doesn’t fit normal assumptions – another attraction!

For the sake of comparison (for the 50’) I calculated on the basis of;

Sail area 774 sq ft
Displacement (empty) 6,720 lb’s
Displacement (full) 10,528 lb’s
LOA 50’
LWL 50’
Beam 27’

If I’d an engineering background I’d have a clue as to the adjustments I need to make for the asymmetry. Sadly, I don’t L.

From the above figures – the 50’ seems faster than the FastCat 435 at “full load” (and there’s going to be a lot to debate on what “full load” means - but the SA/D’s are similar) and a little below that of a Catana 44 sailing downwind.

I’d be interested to learn from comments as to revisions required for asymmetry and the SA/D result. I’m sure adjustment needs made – the “motion comfort ratio” (a function of; displacement, beam, LWL and LOA) gives a figure of 8-10 for most cat’s. The FastCat is a little less than 8 and some cruisers are around 10. The HarryProa ratio comes out at 2.6 – a huge difference!

Displacement to Beam/LWL/LOA is supposed to be an indicator – is it valid in this case – or perhaps I need to revise my figures?
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Old 18-03-2008, 11:10   #34
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Originally Posted by Rubicon View Post
Rob

I know you've not had a chance to think about my last post but I just entered some of your figures to calculate speed potential, SA/D and the motion comfort ratio. I believe I've the formulae correct but I'm not at all sure how they should be adjusted to reflect the asymmetry. Your design just doesn’t fit normal assumptions – another attraction!

For the sake of comparison (for the 50’) I calculated on the basis of;

Sail area 774 sq ft
Displacement (empty) 6,720 lb’s
Displacement (full) 10,528 lb’s
LOA 50’
LWL 50’
Beam 27’

If I’d an engineering background I’d have a clue as to the adjustments I need to make for the asymmetry. Sadly, I don’t L.

From the above figures – the 50’ seems faster than the FastCat 435 at “full load” (and there’s going to be a lot to debate on what “full load” means - but the SA/D’s are similar) and a little below that of a Catana 44 sailing downwind.

I’d be interested to learn from comments as to revisions required for asymmetry and the SA/D result. I’m sure adjustment needs made – the “motion comfort ratio” (a function of; displacement, beam, LWL and LOA) gives a figure of 8-10 for most cat’s. The FastCat is a little less than 8 and some cruisers are around 10. The HarryProa ratio comes out at 2.6 – a huge difference!

Displacement to Beam/LWL/LOA is supposed to be an indicator – is it valid in this case – or perhaps I need to revise my figures?

In my opinion you don't need to adjust the SA/D ratio, this is a fact. It will be faster than a fastcat, as they can't sail at windspeed with any load on board. This is based on their published vector diagram, and these are normally optimistic as they are used in marketing the product, (just my personal opinion - specs are normally based on best case scenarios)

Maybe if you posted the formulae you are using we can better comment on them. How do you calculate the motion comfort ratio? Never seen it before.

Regards

Alan
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Old 18-03-2008, 11:57   #35
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Alan - the formula is

MCR = Disp / (2/3*((7/10 * LWL)+(1/3 *LOA))*Beam4/3)

It's not my formula but one I found at US Sailing Course and Online Sailing School
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Old 18-03-2008, 12:05   #36
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Alan - I'm sure you're correct about the FastCat - but the FastCat spec for finished product includes a great deal more than the HarryProa. The finished FastCat may even include equipment that would exceed or approach the HarryProa's max load.

I have this vision of imminent death after placing weighing scales on the marina before letting the wife on board!
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Old 18-03-2008, 12:22   #37
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Alan - I'm sure you're correct about the FastCat - but the FastCat spec for finished product includes a great deal more than the HarryProa. The finished FastCat may even include equipment that would exceed or approach the HarryProa's max load.

I have this vision of imminent death after placing weighing scales on the marina before letting the wife on board!
You need to compare the prices as well, there is a big difference between 200 k€ and 600k€. For that kind of budget you could probably get a 70 ft harryproa with all modcons.
May I suggest that you make yourself a list of what creature comforts you must have, put them in a spreadsheet. I'm in the process of designing a boat so probably have most figures for weights available if you need any help.

Then contact Rob Denney and see what he suggests, he does have a cruiser version that will take more load, or maybe scale it up.

I've checked out a number of yards in South Africa, so if you need any ideas then let me know. My boat will be built down there - starting in a few months time.
I know that there is at least one other member on this forum who is contemplating a Harryproa build in Capetown..

Regards

Alan
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Old 18-03-2008, 13:36   #38
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We must have like minds Alan - I have been doing exactly as you suggested and putting down on a spreadsheet the components I'd like. Thanks very much for the offer of help - I'll get back to you once I've arrived at a sensible array. SA construction also seems a lot more realistic than Australia.

(Nothing against Australia but I flew there a little over a year ago. As we approcahed the Western Aus coast I thought "Great! Can't be too much longer". 5 hours later I was still looking out on wilderness!)
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Old 18-03-2008, 16:32   #39
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Quote:
Originally Posted by Rubicon View Post
Rob

I know you've not had a chance to think about my last post but I just entered some of your figures to calculate speed potential, SA/D and the motion comfort ratio. I believe I've the formulae correct but I'm not at all sure how they should be adjusted to reflect the asymmetry. Your design just doesn’t fit normal assumptions – another attraction!

For the sake of comparison (for the 50’) I calculated on the basis of;

Sail area 774 sq ft
Displacement (empty) 6,720 lb’s
Displacement (full) 10,528 lb’s
LOA 50’
LWL 50’
Beam 27’

If I’d an engineering background I’d have a clue as to the adjustments I need to make for the asymmetry. Sadly, I don’t L.

From the above figures – the 50’ seems faster than the FastCat 435 at “full load” (and there’s going to be a lot to debate on what “full load” means - but the SA/D’s are similar) and a little below that of a Catana 44 sailing downwind.

I’d be interested to learn from comments as to revisions required for asymmetry and the SA/D result. I’m sure adjustment needs made – the “motion comfort ratio” (a function of; displacement, beam, LWL and LOA) gives a figure of 8-10 for most cat’s. The FastCat is a little less than 8 and some cruisers are around 10. The HarryProa ratio comes out at 2.6 – a huge difference!

Displacement to Beam/LWL/LOA is supposed to be an indicator – is it valid in this case – or perhaps I need to revise my figures?
Hallo Rubicon

I do have an engineering background and my calculation works out different
If the Harry Proa has 775 squire feet of sail area or 65 squire meter and has a loaded weight of 5000 kilo, this is a weight to sail to weight ratio of 1 (ton): 12 (Squire meters )
Now if we take the bare FastCat with the same usefull load of 1500 kilo,s or a total weight of lets say 7000 kilo, and 120 squire meters of sail area or a ratio of 1 : 17 that should make the FastCat faster and the FastCat is a spacious comfortable sailing machine large enough to live on for long periods,
Now if we load up the FastCat to its maximum alllowed load we go up to 11500 kilo,s or a payload of 6000 we now have a weight to sail ratio of
1:10 now the harry Proa is the faster boat but 3500 kilos extra load on board There is something to say for both sailing machines just very different.
Greetings
Gideon
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Old 18-03-2008, 17:34   #40
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Gideon

I'm in no position to challenge nor do I think there a reason to. There's a danger of comparing apples and oranges. My main concern was the low comfort stat associated with the HarryProa and whether the stat had much meaning.

Having said that - there is a curiousity I have and want to explore. There's no doubt in my mind that the FastCat is a superbly designed yacht with forward looking concepts based on experience and deliberate intent to 'push the bubble'.

To be honest, I am trying to make an apple out of an orange. My reason is money and time. The sooner I can get a live-aboard the better (for me) - but I've a domestic propaganda campaign to mount too.

The Harryproa design is interesting - but it will emerge through a lot of individual effort that'll take the concept forward.

OK - I'll come clean; I want the Harry with the same comfort and safety as the FastCat - but cheaper and sooner. It'll be impossible but I'm very interested in what a compromise might look like.
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Old 18-03-2008, 18:43   #41
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G'day,

Answers after your questions:
Quote:
Originally Posted by Rubicon View Post
Rob

Rubicon I’ve checked out your site – it took me a little time to get used to the design but the more I thought about it the more I liked it. The 50’ seems to sail very fast (15 knots at 15 knots wind speed on the YouTube video) and added safety of the design are both strong selling points – as is the construction cost.

I’ve a few issues:

The payload seems low (3,808 lbs) – particularly once outboard, fuel, water, batteries, solar panels, nav. gear are added in. After that there’s the weight of the crew to add in plus personal items.

Rob I don't like short heavy boats. They don't sail well, don't have a nice motion and feel like they are always trying to push a mountain of water out of the way. Coming from monos, cruising cats feel fast. Coming from racing cats and tris, they feel sluggish. Proas don't, as you can see from the video. There is no reason why you cannot exceed the weights given, as long as the weight in the windward hull stays pretty much the same. Loading up the lee hull will slow the boat, but otherwise not make a lot of difference. This is in direct contrast to overloading a cat which immerses the transoms and applies loads to the structure which it was not designed to take. Having said this, if you want a fast boat, choose a length appropriate for the weight you want to carry.

Rubicon The saloon and interior seems tight – particularly for live-aboard / long-cruises.

Rob
They are. The original Visionarry was for taking 8 sight impaired people and 2 crew day sailing in Holland, and/or 4 adults and 4 kids cruising for weekends and their annual holidays, both of which it does well. The second one was built in Australia for an owner that wanted an enclosed saloon. Rare Bird (in the video) is the result. It is heavier and less sleek than Blind Date. Apart from a bit more ww hull, it is the same basic boat. There is another one almost ready for launch in Finland, with a totally enclosed saloon. I am not sure about the weight of this one, but it should be less than Rare Bird. A couple of Norwegians wanted something similar payload wise, and are building a 20m version.

Rubicon Perhaps my concerns are misplaced – the saloon diagram I find a little difficult to visualise. My simple brain works better with planar views. Would modifications / additions be required for cold climate sailing; e.g., building materials, heating etc.?

Rob The Finns are on the Arctic Circle, the Norwegians above it! 25 and 30mm foam core, good ventilation, double glazed windows and a powerful heater seem to be the requirements.

Rubicon You mentioned (above) that you’ve a 60’ design and I wonder to what extent the living space and payload issues are resolved in this new design?

Rob Dramatically. It has 2 island bed double cabins with en suites in the ww hull, which are at the same level as the galley and table. No accommodation below the bridge deck, or below the water. The lee hull in the charter version has 2 double cabins with en suites, floor below the waterline, but the hull only draws 18". Payload 3 tonnes, but no problem increasing this. I do not have access to the web page at the moment (long story) so cannot post anything, but if you and anyone else want to let me know an email address, I can send some layout pictures.

Rubicon The conversion to electricity seems a good idea but I wonder if you’ve had time to consider the weight impacts? Gideon also seems to have designed a useful wind-generator mounted on top of the main – could this be incorporated in to your design?

Rob The charter boat will have a gen set so not a huge battery load. The non diesel harryproa would either have to pay a weight penalty, a cost penalty (lithium ion batteries), or accept that they are not going to be able to motor long distances. With the sailing performance of the proa, this may not be a huge price to pay. Masthead wind generators could be used, but I don't like weight aloft, nor do I fancy going up there to fix it, or to cut the wires if it blows off and is dangling. I hope Gideon will tell us this is not possible, but I worry about this sort of thing. I don't think the advantages outweigh the disadvantages, but it is your choice. A wind charger on a short mast on the ww hull makes more sense to me, if they are quiet enough. Can add radar, wind gear, aerials and anything else you fancy, make the mast fold and maintenance become far easier. Bit less breeze down there, but if you are sailing at windspeed, should be more than enough.

Rubicon Finally, the construction issue is playing on my mind. Ideally I’d prefer the designer to do the build and put in the electrics, tanks, pumps, nav. equipment etc. at the same time. I believe you offer such a service. Without specifics you’ll not be able to provide an estimate of costs but perhaps you could advise on the standard construction costs for the 50’ and 60’ designs?

Rob We built Rare Bird, but have stopped building in Australia as it is too expensive. We are sending out tenders for the charter proa to yards in Peru, Brazil and South Africa. Anyone knowing any yards, please let me know. I am also looking pretty seriously at setting up a yard in Panama with a kiwi who lives there and knows how the local system works. Whichever way we go, I expect to be pretty involved in the building and fit out process. Rare Bird cost $AUS400k including a lot of messing about. It is cedar strip. The charter boat is flat panels, including a rounded bottom, which is pretty easy with a zero rocker hull. Ballacotta in Peru Kelsall Catamarans - Ballotta Catamarans - Custom built catamarans - Prices build low cost Kelsall 46 cats and they are our benchmark. If our shell and beam costs are not cheaper than their shell cost, the charter boat won't be built. So far, it looks like we will be, by a large margin. The surface area is less, the construction technique is even quicker than KSS and as the accommodation is all on one level, the entire saloon, including walls, doors and roof is built on the floor then raised and bonded onto the hull.

Rubicon(After that I’d need to think of how to get the boat to Ireland – but taking a year off work may provide an attractive solution …)

Rob Yes indeed. The charter company is also looking for more boats to run, so their are other options as well.

Thanks – and the best of luck in taking this forward!
Ta. More than luck, I need more hands. There have been 3 serious enquiries for 60 footers in the past 3 days. All of them with very different requirements.

regards,

Rob
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Old 18-03-2008, 19:02   #42
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Formulae and performance

G'day,

No idea what adjustments are needed for assymetry.

No time at the moment to check and comment on the formulae. And no wish to get into a pissing contest with Gideon, who is doing more to advance performance of cruising cats than anyone else. just waiting for him and Alan to see the light and help me do the same to harryproas. ;-)

On comparative performance, I think the video says it all. Bear in mind that this is an overweight boat (3 tonnes vs Blind Date at 2 and a bit). The sails are not matched to the mast (small job, no one has got round to it) and the mast was designed for the lighter weight so it flexes more than it should. The boat is ready for long term warm weather cruising. As you can see in the video, no one is trying very hard to make it sail fast. This is the first of it's kind, there is plenty more performance available.

Yet it sails at windspeed in breeze of 10-15 knots. There are no videos of cruising cats doing anything like this, as far as I know. An Atlantic 48 doing 12 in 20, a Catana doing 18 in 25 while racing (and making very hard work of it) and not much else.


Regards,

Rob
Quote:
Originally Posted by Rubicon View Post
Rob

I know you've not had a chance to think about my last post but I just entered some of your figures to calculate speed potential, SA/D and the motion comfort ratio. I believe I've the formulae correct but I'm not at all sure how they should be adjusted to reflect the asymmetry. Your design just doesn’t fit normal assumptions – another attraction!

For the sake of comparison (for the 50’) I calculated on the basis of;

Sail area 774 sq ft
Displacement (empty) 6,720 lb’s
Displacement (full) 10,528 lb’s
LOA 50’
LWL 50’
Beam 27’

If I’d an engineering background I’d have a clue as to the adjustments I need to make for the asymmetry. Sadly, I don’t L.

From the above figures – the 50’ seems faster than the FastCat 435 at “full load” (and there’s going to be a lot to debate on what “full load” means - but the SA/D’s are similar) and a little below that of a Catana 44 sailing downwind.

I’d be interested to learn from comments as to revisions required for asymmetry and the SA/D result. I’m sure adjustment needs made – the “motion comfort ratio” (a function of; displacement, beam, LWL and LOA) gives a figure of 8-10 for most cat’s. The FastCat is a little less than 8 and some cruisers are around 10. The HarryProa ratio comes out at 2.6 – a huge difference!

Displacement to Beam/LWL/LOA is supposed to be an indicator – is it valid in this case – or perhaps I need to revise my figures?
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Old 18-03-2008, 19:16   #43
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G'day,

Yet it sails at windspeed in breeze of 10-15 knots. There are no videos of cruising cats doing anything like this, as far as I know. An Atlantic 48 doing 12 in 20, a Catana doing 18 in 25 while racing (and making very hard work of it) and not much else.


Regards,

Rob
Here's a very short video I took on an Oram 38 "Mango" sailing at 12-13 knots in around 15. Not quite 100% TWS, but not far off. The boat was quite heavily loaded, (I'm sure we were overloaded according to some)with 4 (big) guys, about 200 beers, and plenty of food, genset, dinghy, outboard, etc etc.

Also we still had a reef in and slightly furled headsail due to stronger winds experienced prior .

(Excuse the sound quality, it was taken using a digital still camera.)

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Old 19-03-2008, 00:12   #44
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Quote:
Originally Posted by Rubicon View Post
Gideon

I'm in no position to challenge nor do I think there a reason to. There's a danger of comparing apples and oranges. My main concern was the low comfort stat associated with the HarryProa and whether the stat had much meaning.

Having said that - there is a curiousity I have and want to explore. There's no doubt in my mind that the FastCat is a superbly designed yacht with forward looking concepts based on experience and deliberate intent to 'push the bubble'.

To be honest, I am trying to make an apple out of an orange. My reason is money and time. The sooner I can get a live-aboard the better (for me) - but I've a domestic propaganda campaign to mount too.

The Harryproa design is interesting - but it will emerge through a lot of individual effort that'll take the concept forward.

OK - I'll come clean; I want the Harry with the same comfort and safety as the FastCat - but cheaper and sooner. It'll be impossible but I'm very interested in what a compromise might look like.
Hallo Rubicon

I am sure the HarryProa will cheaper and maybe sooner but comfort and space cannot be compared. what is more important than top speed is average cruising speed and both the Harry Proa and the FastCat are very good sailors in light winds

good luck with your choice , if you need any help: ask.

Greetings
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Old 19-03-2008, 00:51   #45
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Here's a very short video I took on an Oram 38 "Mango" sailing at 12-13 knots in around 15. Not quite 100% TWS, but not far off. The boat was quite heavily loaded, (I'm sure we were overloaded according to some)with 4 (big) guys, about 200 beers, and plenty of food, genset, dinghy, outboard, etc etc.

Also we still had a reef in and slightly furled headsail due to stronger winds experienced prior .

(Excuse the sound quality, it was taken using a digital still camera.)


Looks good Cruisingcat! How heavy is the boat would you reckon?

There aren't many cruising cats that can do that speed in 15 knots TWS, just shows that Bob Oram knows what he's doing.

Where did you get the composite stanchions from?

Regards

Alan
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