Ron Givens Design and length vs complexity

[brian.cunningham]

While reading the lastest copy of Multihulls Magazine, I noticed an article on Ron Givens' Oceansurfer.
http://www.multihullsmag.com/magazine/magazine.htm


At first I thought I was looking at beach cat, but then it turns out the boat is 62ft long with a 37ft beam and a 82ft mast! with 30knot speeds. Which is cool for a racer, but not a good cruiser, but wait a minute there's actually room for a king sized bed in each hull! It seems to have small extensions under the central tramp.

Anyone familiar with his designs?
Does he have a website?

Also, this boat really begs the question, is it better to complicate a design to fit the most in for a given length, or keep it as simple as possible and just make it bigger. Thus making it cheaper to build, but also lighter and faster.

Brian T. Cunningham, EIT

[John B]

http://www.givencats.com/

[John B]

This one was parked backed onto us while hauled this year.

A bit of a sad story . The new owner was telling me about the guy who built it as his retirement dream boat. They were sailing along at 10 or 12 when he went forward to clear a line and fell over the bow. He was run down and collected by the centreboard as he went through.He survived but it smashed him up pretty badly and he's finished boating for life.

[brian.cunningham]

That was quick, thanks!
( don't know why I couldn't Google it )

[brian.cunningham]

(seems the forum is mixing up posts again )

Originally posted by John B:
This one was parked backed onto us while hauled this year.

Sorry to hear about the owner, how he fell off that huge tramp is beyond me.

Neat design though

DOUBLE DIAMOND
A different approach to the performance weekender sailing catamaran, in that a simple single chined plywood hull form is used - a way of reducing costs - with a little more interior space and comfort than most weekenders.

This yacht will be used by a couple for weekend cruising, winter racing and 1 or 2 extended cruises per year.

Having been involved off and on with chined catamaran hull construction for more than 30 years, I know that the top end performance of these craft can surprise the disbelievers.

[Hwyl]

This is more your style Brian

[John B]

A line fouled around the bow and he leant forward to clear it Brian.
She's a fine looking boat in the flesh.

[John B]

(()*&^% edit.

Split Enz (The pink one) held all sorts of records here. She went to New Caledonia I think. IIRC she was damaged in a cyclone over there. Not sure if she's back in the water yet.

[John B]

every kiwi sailor, multi or not knows of Ron Given.

http://www.papertiger.org.nz/histroy.htm

and Tennant, and Farrier.

[brian.cunningham]

Ah, newbie mistake turns tragic

Originally posted by John B:
every kiwi sailor, multi or not knows of Ron Given.

http://www.papertiger.org.nz/histroy.htm

and Tennant, and Farrier.

Neat little boat.

I'm glad I'm looking into this designer.

Originally posted by Hwyl:
This is more your style Brian

Most definitely, but it's also definitely a day sailer/hard core racer.

As you can see the crossbeams need to be a certain hieght to take the load, basic beam theory. The length is there to get an airfoil shape. You can see if the boat was scaled up you'd be able to stick a berth in there. Just like the 1st photo. Hence the question.

For instance, this one has both 2 single, and 2 double berths


You can get really eleborate with a cruiser cat, but boats like the one below loose a lot of performance due to windage, but they are GREAT to live on!




[ 12-12-2005, 12:43 AM: Message edited by: brian.cunningham ]

[brian.cunningham]

RATS

In a message dated 1/6/2006 5:25:34 AM Eastern Standard Time, info@givencats.com writes:
John P Davis
Thanks for your enquiry and comments.
"OCEAN SURFER" is a custom design built with basic
hulls,beams.rig,sailplan drawings and the rest by direct personal
consultation by myself with the NZ builder.
It would not be economic for me to do a complete set of drawings for
amateur construction for such a special craft
Regards
Ron Given

---- Original Message ----
From: jpdavis@mindspring.com
To: info@givencats.com
Subject: RE: Oceansurfer
Date: Mon, 12 Dec 2005 17:06:58 -0500

>Hello,
>
>I have been admiring your large minimalist cat Oceansurfer. It is
>close
>to what I am interested in as a cruising cat. Do you have any other
>pictures of her that you could send me particularly of the
>undersides,
>hull shape and rigging layout. Thanks and congratulations on a classy
>looking cat.
>
> Brian T. Cunningham

[brian.cunningham]

I just got the latest magazine, and it has an interview with one of my favorite designers, Chris White

On this subject
http://www.chriswhitedesigns.com/concept63/index.php

Longer is Better

Catamarans sail best when the hulls are very narrow for a given length. The slender hulls create less wave making resistance at higher speeds allowing better acceleration through the 10 to 12 knot "resistance hump" that many fuller bodied cats experience. Also a significant gain in seakeeping, comfort in waves, is experienced due to the narrow area of water plane. In simpler terms, slender hulls more easily slice through waves and do it with less pitching and rolling.

The disadvantage to narrow hulls is that the volume below decks is reduced and this generally makes it impractical to design a cruising cat less than 60' in length with hulls as fine as desired. However, if the length of the boat is allowed to stretch out to 60' or more while at the same time keeping the overall weight of the vessel down to the lower end of cruising displacement spectrum an extremely efficient hull form results that, due to its sheer size, has plenty of internal volume to provide excellent accommodations.

The Case for Limiting Size

The size of a boat is a product of many dimensions, length, width, height, surface area, and weight. While increasing the length of the hulls is very desirable it is not always as beneficial to increase all other dimensions. While longer is better, bigger boats cost significantly more to construct and require a great deal more effort to sail. The typical 60+' catamaran is often a VERY large boat. With overall beam of 30' or more, a loaded displacement of 50,000 lbs. and a mainsail of 1,000+ sq/ft which weighs upwards of 300 lbs. Cats of this magnitude are usually too large to be handled without experienced full time help. And the sheer size and weight of sails necessitates electric or hydraulic powered winches for halyards and sheets; adding further to the weight, complexity and cost of the vessel. Also, the mast height of a sloop rigged cat is well over 65' which prohibits access to much of the Intracoastal waterway and other harbors that could provide shelter in a blow.

Therefore, in the design of the Concept 63, the primary goal was to incorporate the benefits of long slender hulls without making the vessel so large and unwieldy that it no longer can be handled safely by a cruising couple or family.

...

Sailplan

A modern ketch rig with fully battened main and mizzen and roller furling jib is appropriate for this design. A ketch splits the sails to more easily managed size and keeps the center of effort low which is more in keeping with the design concept of moderate overall beam. It also offers substantial advantages for offshore sailing; a reefed mizzen makes a great riding sail while waiting out a gale either hove to or hanging on a parachute anchor. Ketch rigged boats are also extremely fast. While they typically give up a slight bit (approximately 3%) of windward ability in light air compared to sloops this is usually of little concern in a cruising context because usually once boat speed drops to 6 knots or less the engines are started.

Masthead height is under 65' from LWL. As previously mentioned, this offers increased flexibility in cruising the East and Gulf coast since the Intracoastal Waterway is always an option in foul weather as well as other harbors that are obstructed by highway bridges or power lines. To take full advantage of the super shoal draft possible in a cruising cat it is also necessary to keep the overhead clearance below 65'.

Spinnaker and mizzen staysail can be flown in light winds for incredible off wind speed. Using both of these sails should enable reaching speeds nearly 1.5 times wind speed in light wind conditions. There is nothing as fast a ketch on a reach. Just look at the favored big boat rig among the round the world racers of the Whitbread Race, they are nearly all ketches.

I've always liked split rigs better [img]smile.gif[/img]