Re: Stus-List Windows and floorboards add strength

[Martin DeYoung via CnC-List]

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" 
To: "Chuck S" , 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 
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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Re: Stus-List Windows and floorboards add strength

[Chuck S via CnC-List]

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 

- Original Message -

From: "dwight"  
To: "Chuck S" , 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 


On Sat, Feb 14, 2015 at 1:23 AM, Chuck S via CnC-List < 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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Re: Stus-List Windows and floorboards add strength

[dwight veinot via CnC-List]

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


On Sat, Feb 14, 2015 at 1:23 AM, Chuck S via CnC-List  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.
>
>
>
> --
> *From: *"Frederick G Street via CnC-List" 
> *To: *"dwight" , cnc-list@cnc-list.com
> *Sent: *Thursday, February 12, 2015 2:53:25 PM
> *Subject: *Re: Stus-List Window Installation - 1985 41
>
> Dwight — if I might jump in here, my understanding is that the glued-in
> acrylic ports became a unified part of the cabintop structure, and
> stiffened the structure; NOT that they made the boat stiffer in terms of
> sailing characteristics.
>
> Fred Street -- Minneapolis
> S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI   :^(
>
> On Feb 12, 2015, at 1:15 PM, dwight veinot via CnC-List <
> cnc-list@cnc-list.com> wrote:
>
> Rick
>
> Is it really true that the designers at C&C expected glued on acryllic
> ports to stiffen the whole boat
>
> Dwight Veinot
> C&C 35 MKII, *Alianna*
> Head of St. Margaret's Bay, NS
> d.ve...@bellaliant.net
>
>
>
> ___
>
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Re: Stus-List Windows and floorboards add strength

[Russ & Melody via CnC-List]

Chuck.

Please stop at "I'm not an engineer."

You are correct in the window muse. The design 
does add to overall deck stiffness which 
contributes to structure stiffness. This is not 
to be confused with increased righting moment by anyone, I hope.


Regarding floorboards, do you mean the sole or 
the floors? And by stiffening the design, do you 
mean "She can carry more sail with this 
improvement!"  (the aforementioned right moment) or a less springy sole?
There are far too many areas to list in weight 
saving activities before considering a move to an aluminum honeycomb sole.


I ask not facetiously but because Amazing Grace 
has Kevlar reinforce floors and a normal teak & 
holly plywood sole. This boat was a "no expense 
spared" racing machine in the early 80s, to show 
they had it figured out way back when.


Cheers, Russ
Sweet 35-1

At 09:23 PM 13/02/2015, you 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.





--
From: "Frederick G Street via CnC-List" 
To: "dwight" , cnc-list@cnc-list.com
Sent: Thursday, February 12, 2015 2:53:25 PM
Subject: Re: Stus-List Window Installation - 1985 41

Dwight — if I might jump in here, my 
understanding is that the glued-in acrylic ports 
became a unified part of the cabintop structure, 
and stiffened the structure; NOT that they made 
the boat stiffer in terms of sailing characteristics.


Fred Street -- Minneapolis
S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI   :^(

On Feb 12, 2015, at 1:15 PM, dwight veinot via 
CnC-List <cnc-list@cnc-list.com> wrote:


Rick

Is it really true that the designers at C&C 
expected glued on acryllic ports to stiffen the whole boat


Dwight Veinot
C&C 35 MKII, Alianna
Head of St. Margaret's Bay, NS
d.ve...@bellaliant.net



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Re: Stus-List Windows and floorboards add strength

[Chuck S via CnC-List]

Dwight, 
I also agree with your earlier comment. 


Chuck 
Resolute 
1990 C&C 34R 
Broad Creek, Magothy River, Md 

- Original Message -

From: "Chuck S via CnC-List"  
To: "CNC boat owners, cnc-list"  
Sent: Saturday, February 14, 2015 12:23:42 AM 
Subject: Re: Stus-List Windows and floorboards add strength 

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. 



- Original Message -

From: "Frederick G Street via CnC-List"  
To: "dwight" , cnc-list@cnc-list.com 
Sent: Thursday, February 12, 2015 2:53:25 PM 
Subject: Re: Stus-List Window Installation - 1985 41 

Dwight — if I might jump in here, my understanding is that the glued-in acrylic 
ports became a unified part of the cabintop structure, and stiffened the 
structure; NOT that they made the boat stiffer in terms of sailing 
characteristics. 

Fred Street -- Minneapolis 
S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( 

On Feb 12, 2015, at 1:15 PM, dwight veinot via CnC-List < cnc-list@cnc-list.com 
> wrote: 




Rick 

Is it really true that the designers at C&C expected glued on acryllic ports to 
stiffen the whole boat 

Dwight Veinot 
C&C 35 MKII, Alianna 
Head of St. Margaret's Bay, NS 
d.ve...@bellaliant.net 






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Re: Stus-List Windows and floorboards add strength

[Chuck S via CnC-List]

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. 



- Original Message -

From: "Frederick G Street via CnC-List"  
To: "dwight" , cnc-list@cnc-list.com 
Sent: Thursday, February 12, 2015 2:53:25 PM 
Subject: Re: Stus-List Window Installation - 1985 41 

Dwight — if I might jump in here, my understanding is that the glued-in acrylic 
ports became a unified part of the cabintop structure, and stiffened the 
structure; NOT that they made the boat stiffer in terms of sailing 
characteristics. 

Fred Street -- Minneapolis 
S/V Oceanis (1979 C&C Landfall 38) -- on the hard in Bayfield, WI :^( 

On Feb 12, 2015, at 1:15 PM, dwight veinot via CnC-List < cnc-list@cnc-list.com 
> wrote: 




Rick 

Is it really true that the designers at C&C expected glued on acryllic ports to 
stiffen the whole boat 

Dwight Veinot 
C&C 35 MKII, Alianna 
Head of St. Margaret's Bay, NS 
d.ve...@bellaliant.net 






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