On the topic of C&C hull strength, while reviewing the original build drawings from the C&C collection at the Museum of the Great Lakes I noticed that the 43's built after hull #8 had an additional "fore gripe".
This fore and aft stringer type re-enforcement runs from the mast step forward about 7'. It was also added to the early C&C 61 Sorcery to fix the same flex point. This flex point starts where the lead section of the keel joins the hull. Both the early 61's and 43's flexed more than expected at that point. This is the same area that we, the current care takers of hull #1 had to repair in 1999 when we first had the boat in Seattle. It is a relief to now know why the hull needed repair in that area. We will be adding a similar "fore gripe" as part of our ongoing deck and interior restoration project. Calypso originally had the oval aluminum framed windows. A prior owner cut those out, added another cut out and bolted on thick acrylic. We replaced the acrylic in 2001 and improved the through bolt system. In 2013 we removed all the balsa core in the window attachment area and filled with thickened epoxy. No more leaks and a much stronger assembly. I do believe that with the longer, larger window openings the bolted acrylic assembly adds stiffness to the cabin top, both fore and aft and athwart ships. I tested some of the cabin top flexibility while removing other hatches and supports. It wiggled more than I expected, especially up and down. Martin Calypso 1971 C&C 43 Seattle ________________________________ From: CnC-List [cnc-list-boun...@cnc-list.com] on behalf of Chuck S via CnC-List [cnc-list@cnc-list.com] Sent: Sunday, February 15, 2015 9:21 AM To: dwight Cc: CNC boat owners, cnc-list Subject: Re: Stus-List Windows and floorboards add strength Hi Dwight, By "fixed", I mean they "don't open". I also agree that the newer frameless windows aren't better than framed, and I don't think I implied that they add strength to what could have been a solid fiberglass coach roof. I just think the coachroof is stronger with the windows intact, like a car's structure is stronger with the doors closed. Windows with cracks (especially frameless type) weaken the coachroof structure slightly. And will allow more flexing and more cracks will develop over time. Chuck Resolute 1990 C&C 34R Broad Creek, Magothy River, Md ________________________________ From: "dwight" <dwight...@gmail.com> To: "Chuck S" <cscheaf...@comcast.net>, cnc-list@cnc-list.com Sent: Sunday, February 15, 2015 10:00:35 AM Subject: Re: Stus-List Windows and floorboards add strength Chuck, What do you mean by "fixed windows?" Aren't all good ports (windows) fixed to the coachouse, glued on, bolted on or other? I think maybe the ports that were glued on with Plexus and found on the 80's C&C designs were done that way mostly for appearance and not necesarily to add strength...I am skeptical about whether or not they added anymore strength than the framed ports did on the older (70's) designed boats. Dwight Veinot C&C 35 MKII, Alianna Head of St. Margaret's Bay, NS d.ve...@bellaliant.net<mailto:d.ve...@bellaliant.net> On Sat, Feb 14, 2015 at 1:23 AM, Chuck S via CnC-List <cnc-list@cnc-list.com<mailto:cnc-list@cnc-list.com>> wrote: I'm not an engineer but I do re-engineer many systems they dream up. I think the fixed windows do add strength and without them the structure has to be weaker. They help support the coachroof which does create an arch between the flatter deck sections. Also, floorboards. You might stiffen up an old design by changing from wooden plywood to an aluminum honeycomb sandwich. But would the cost be worth it? Probably not unless you needed to replace them.
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