LOCK CROWTHER DESIGN NOTES AS PROMISED

cat man do · 23-11-2006, 17:38

As promised in a previous post somwhere I have managed to supply Lock Crowthers thought's on multihul design and constuction.

As mine were water damaged, I would like to thank Stuart Bloomfield for supplying these.

He was one of the designers at Crowther Designs, and now runs his own office and I believe can still supply the old stuff as well as his new designs.
http://www.bloomfieldinnovation.com/

Very interesting are his findings on wave induced capsize.

These may have lost some image quality as I got them in 800 kb files and had to reduce them for you to view here.

Enjoy

Dave

**Kai Nui** · 23-11-2006, 17:53

Good job on the photos. Completely readable. Interesting article

cat man do · 23-11-2006, 20:08

Suprised myself they came out that clear.

An important peice of multihull history that should not be lost

fhrussell · 27-11-2006, 07:48

Great! Thank you!!.......

Intentional Drifter · 27-11-2006, 09:09

That was good stuff. Thanks, and the scans came out great.

ID

OldYachtie · 05-09-2007, 22:19

He mentioned balsa soaking up a lot of resin. You can buy pre-coated balsa that has a factory finish that prevents that. (Baltek al-600/10 is the best known example.) Balsa is still a bit heavier than foam if you use the cheaper standard grade, but only about 400 pounds for a 65' boat. It is much cheaper, and much stronger than foam. Balsa/vinylester is used in, for example, J-boats.

cat man do · 06-09-2007, 00:42

Epoxy thank's, the only resin that sticks to timber succesfully is epoxy, everything else is a compramise on strength.

And then you have the different weights of glass, you will usualy use less glass on timber core than foam, therefore less resin, and I always use less epoxy than I do Vinyl and Poly, so I won't/don't use Poly or Vinyl for anything.

The reason the comments may be out of date is because Lock passed away several years ago while sailing Deguello off the East coast of Australia.

Dave

rgwla · 30-03-2008, 15:16

Thanks for the notes, "CatManDo". I am restoring a Crowther designed 42' Tri. She was VERY wet when I got her, but well built to start....

Southern Star · 30-03-2008, 18:40

Thanks Cat - very interesting read.

Brad

23-11-2006, 17:38	#1
cat man do Registered User Join Date: Aug 2006 Location: Brisbane Australia [until the boats in the piss] Boat: 50ft powercat, light,long and low powered Posts: 1,791 Images: 35	LOCK CROWTHER DESIGN NOTES AS PROMISED As promised in a previous post somwhere I have managed to supply Lock Crowthers thought's on multihul design and constuction. As mine were water damaged, I would like to thank Stuart Bloomfield for supplying these. He was one of the designers at Crowther Designs, and now runs his own office and I believe can still supply the old stuff as well as his new designs. http://www.bloomfieldinnovation.com/ Very interesting are his findings on wave induced capsize. These may have lost some image quality as I got them in 800 kb files and had to reduce them for you to view here. Enjoy Dave Attached Thumbnails __________________ "Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth http://www.thecoastalpassage.com/ Last edited by cat man do; 23-11-2006 at 17:44.

23-11-2006, 17:53	#2
Kai Nui Captain Site Administrator Join Date: Jul 2005 Location: Moss Landing, Ca Boat: 37' Piver Lodestar - Kai Nui Posts: 4,384 Images: 80	Good job on the photos. Completely readable. Interesting article __________________ There is no better bilge pump than a scared sailor with a bucket. KAI NUI

23-11-2006, 20:08	#3
cat man do Registered User Join Date: Aug 2006 Location: Brisbane Australia [until the boats in the piss] Boat: 50ft powercat, light,long and low powered Posts: 1,791 Images: 35	Suprised myself they came out that clear. An important peice of multihull history that should not be lost __________________ "Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth http://www.thecoastalpassage.com/

27-11-2006, 09:09	#5
Intentional Drifter Registered User Join Date: Apr 2006 Location: Pac NW Posts: 506	That was good stuff. Thanks, and the scans came out great. ID __________________ Intentional Drifter Observations are gold; hypotheses, silver; and conclusions, bronze. Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote.--Ben Franklin Everyone is entitled to their own opinion, but not their own facts.--Daniel Patrick Moynihan

05-09-2007, 22:19	#6
OldYachtie Registered User Join Date: Mar 2007 Location: 35 mi. north of Seattle Boat: Building a 65' catamaran at moment Posts: 78	One of the balsa comments was out-of-date He mentioned balsa soaking up a lot of resin. You can buy pre-coated balsa that has a factory finish that prevents that. (Baltek al-600/10 is the best known example.) Balsa is still a bit heavier than foam if you use the cheaper standard grade, but only about 400 pounds for a 65' boat. It is much cheaper, and much stronger than foam. Balsa/vinylester is used in, for example, J-boats.

27-11-2006, 07:48	#4
fhrussell Registered User Join Date: Jan 2006 Location: Long Island, NY Boat: 27' CSK, Hula Kai Posts: 114 Images: 4	Great! Thank you!!.......

06-09-2007, 00:42	#7
cat man do Registered User Join Date: Aug 2006 Location: Brisbane Australia [until the boats in the piss] Boat: 50ft powercat, light,long and low powered Posts: 1,791 Images: 35	Epoxy thank's, the only resin that sticks to timber succesfully is epoxy, everything else is a compramise on strength. And then you have the different weights of glass, you will usualy use less glass on timber core than foam, therefore less resin, and I always use less epoxy than I do Vinyl and Poly, so I won't/don't use Poly or Vinyl for anything. The reason the comments may be out of date is because Lock passed away several years ago while sailing Deguello off the East coast of Australia. Dave __________________ "Money can't buy you happiness but it can buy you a yacht large enough to pull up right alongside it"...............David Lee Roth http://www.thecoastalpassage.com/

30-03-2008, 15:16	#8
rgwla Registered User Join Date: Mar 2008 Posts: 2	Thanks for the notes, "CatManDo". I am restoring a Crowther designed 42' Tri. She was VERY wet when I got her, but well built to start....

30-03-2008, 18:40	#9
Southern Star Registered User Join Date: Dec 2007 Location: Belleville, Ontario, Canada; Playa Zaragoza, Isla de Margarita Boat: 1994 Solaris Sunstream 40 'Estrella del Sur' Posts: 689	Thanks Cat - very interesting read. Brad

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