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  #61  
Old 08-01-2007, 09:28 AM
kengrome kengrome is offline
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The Seaknife by Peter Payne

Quote:
Are there now, after all these years of modern powerboat development, any really satisfactory rough water planing or semi-planing boats that distance themselves from the rest?
There is ONE planing power boat that is designed specifically to function well in rough water -- the Seaknife by Peter Payne:

http://tinyurl.com/26kdo5

This link is a google search with links to most of the available online information about this unique boat and its designer, a genius in my opinion. Some of the yachtforums links are especially interesting.

As far as I know only a few of these boats have ever been built and no one is currently building any. I would love to build one some day because I understand the theory behind Peter Payne's work and I am really surprised that these boats have not been built in great numbers.
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Kenneth Grome
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  #62  
Old 08-09-2007, 03:43 PM
Nojjan Nojjan is offline
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Cats may loose this fight...!?

Please review videos on the attached page and make your own judgement. I say monohulls seem to beat cats, at least in this size class.

http://safehavenmarine.phanfare.com/...mageID=3881288

Take care
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  #63  
Old 08-09-2007, 05:45 PM
northerncat northerncat is offline
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interesting that you should say that as the one! cat there is flying around at about 25knots while the three monos i watched look like they are all around 15knots
sean
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  #64  
Old 08-10-2007, 03:34 AM
allmandboats allmandboats is offline
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smooth riding rough water

After decades designing and manufacturing I have found there are a few different approaches to smooth riding rough or choppy waters. with boats under 30 feet the best design is the true panga. I don't mean the majority of copy boats made to look like a panga from the water line up, rather the panga design originally designed in Japan over 30 years ago. Yes that's right. As we in the west designed our V hulls at the dawn of the fiberglass era that plow through a wave, on the other side of the world they were designing on a different concept to ride above the wave. For boats over 30 feet the length of a even consistent surface is what has made the difference for our 36 foot Samurai. Yes, steps in the hull add performance, but I am refering to what has given our customers the smoothest ride. Our customers have reported smooth riding at 45 knots in 4 to 6 foot seas with our unique 36 Samurai design. There is a definite feel to each application, either the true panga design or the Samuai Vee. By the way, what good is a step in the hull if you still et a rough ride in choppy water?
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  #65  
Old 08-10-2007, 07:47 AM
Verytricky Verytricky is offline
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Quote:
Originally Posted by Pericles View Post
301,574,000 at last count.
That is scary!!!
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  #66  
Old 08-28-2007, 09:39 AM
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Pericles Pericles is offline
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Best I could do.

Dear Pericles,



Thank you for your e-mail – my apologies for the delay in responding but I have been out of the office for a couple of weeks.



I appreciate your support for our boats and the time you have taken to contact us. The reason we do not have more photographs of our boats in rough weather has much more to do with the problems of obtaining photographs than any problems with our boats. You are correct in your supposition regarding the seaworthiness of the boats and we have a number of testaments from owners who have been delighted with the performance of the boats in very severe conditions (one owner claims to have had one of our Wave Farmer class out in 8m seas servicing a fish farm in the Atlantic when quote “nobody else would go out but she was absolutely fine”).



Thank you again for your interest in our boats.



Best Regards





Chris Millman



Managing Director

Alnmaritec Ltd.

Telephone + 44 (0) 1665 602 917

Fax + 44 (0) 1665 605 399

Mobile + 44 (0) 7990 551 509


--------------------------------------------------------------------------------

From: PERRY DEBELL [mailto:cd014j7257@blueyonder.co.uk]
Sent: 26 July 2007 09:38
To: sales@alnmaritec.co.uk
Subject: Photographs of your vessels in appalling weather.



To the Managing Director,

Alnmaritec Ltd



Dear Mr Millman,



The craft you manufacture have become a subject of debate, as to the suitability of catamarans for use in rough weather. This debate is taking place on Boat Designs forum, http://www.boatdesign.net/forums/sho...les#post153627



It would seem that one contributor to the discussion is unwilling to believe, unless he sees with his own eyes, images of your vessels plunging through waves, strong enough to daunt the heart of the most seasoned mariner.



For my part, I have no such reservations about the seaworthiness of your type of catamarans. Would you consider posting your thoughts on the matter for us to share?



Yours sincerely,



Pericles
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  #67  
Old 08-28-2007, 10:21 PM
longliner45 longliner45 is offline
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ok ,,why no photos ,from the boat in rough water,from its own deck??,I can see the argument that no one else was able to be along for the ride to film ( because no other boat was worthy),,,,but,you must know ,,I have fished the north atlantic and off the east coast,,about 700 miles ,and most of the time ,in the gulf of mexico,in the gulf (rode many hurricanes and tropical depresions out),,31 ft jc boats,never seen a cat ,,,please ,,,,,,spare me,,,,,longliner
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  #68  
Old 08-29-2007, 04:12 AM
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Pericles Pericles is offline
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LL45,

Contact Chris Millman and volunteer to take the photos.

In reality, the best rough water boat anyone knows, has to be a nuclear submarine.

Pericles
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  #69  
Old 08-29-2007, 05:58 PM
longliner45 longliner45 is offline
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Ill agree on that,,,,,longliner
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  #70  
Old 08-30-2007, 06:49 PM
FAST FRED FAST FRED is offline
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In reality, the best rough water boat anyone knows, has to be a nuclear submarine.

At 1200 ft .

The argument on "best" is simply a matter of what the crew can take . With a limit of 3G the IN the water boat can go longer/faster than the ON the water cat or other wave leaper.


Staying in contact with the water gives a better ride (lower G's ) (till you go THRU the waves) than crashing from wave top to wave top.

FF
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  #71  
Old 09-14-2007, 03:17 PM
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sottorf sottorf is offline
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Quote:
Originally Posted by xarax View Post
Planing or semi-planing V-hulls have a hard time with short, steep waves. There have been various attemps to address the problem, often stated by many naval designers and owners as doomed to remain unsolved. Are there now, after all these years of modern powerboat development, any really satisfactory rough water planing or semi-planing boats that distance themelves from the rest ?
I agree with the general sentiment that long and narrow is good for seakeeping (not exactly a new concept). Another design that is particularly good is short steep waves in this HYSUCAT = hydrofoil supported catamaran. The hydrofoils between the two hulls provide very good damping of motions and the boats tend to ride on top of the waves rather than piercing through them like long slender hulls. The reason for this has to do with how the hydrofoils react to wave orbital velocity fields. Experiments with HYSUCATS show that yuor vertical accelerations and amplitudes are reduced 30-50% using HYSUCAT designs compared to conventional planing hulls
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  #72  
Old 09-21-2007, 12:23 PM
FAST FRED FAST FRED is offline
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Location: Conn in summers , Ortona FL in winter , with big dock & room for O'nite stop .
The boat book by Dave Geere gives the rules for "Surge" , which if used can lead to as comfortable ride as can be expected till the crew gives out.

Perhaps even MORE important at anchor for a cruiser , than 3G+ bashing Flank Speed.

FF
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  #73  
Old 09-21-2007, 01:35 PM
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sottorf sottorf is offline
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seakeeping of planing hulls

There is a most excellent reference work on seakeeping of planing hulls which I recommend for anybody really wanting to understand seakeeping of fast craft.:

Technical and Research Bulletin No. R-42
SEAKEEPING OF HARD CHINE PLANING HULLS
by Daniel Savitsky and Joseph G. koebel Jr.
June, 1993
Published by SNAME www.sname.org
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  #74  
Old 09-21-2007, 01:37 PM
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sottorf sottorf is offline
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Quote:
Originally Posted by allmandboats View Post
After decades designing and manufacturing I have found there are a few different approaches to smooth riding rough or choppy waters. with boats under 30 feet the best design is the true panga. I don't mean the majority of copy boats made to look like a panga from the water line up, rather the panga design originally designed in Japan over 30 years ago. Yes that's right. As we in the west designed our V hulls at the dawn of the fiberglass era that plow through a wave, on the other side of the world they were designing on a different concept to ride above the wave. For boats over 30 feet the length of a even consistent surface is what has made the difference for our 36 foot Samurai. Yes, steps in the hull add performance, but I am refering to what has given our customers the smoothest ride. Our customers have reported smooth riding at 45 knots in 4 to 6 foot seas with our unique 36 Samurai design. There is a definite feel to each application, either the true panga design or the Samuai Vee. By the way, what good is a step in the hull if you still et a rough ride in choppy water?
Do you have any pictures of the Panga/Samurai hull. It is difficult to comment otherwise
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  #75  
Old 09-22-2007, 04:06 AM
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Pericles Pericles is offline
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A mite longer than a Panga, but Destriero was fast tracked in more ways than one and is single hard chine, designed to be kind to the crew. Page 100 http://www.proboat-digital.com/proboat/20071011/

Pericles
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