[C320-list] Selden Spreader End Cap Installation Query

[Utility Email]

Stephen

I have C320 Mk II hull 1107 and just moved my boat from San Diego to Seattle by truck last month.  I also have a Selden in mast furling rig.  When I unstepped the mast in SD.  I too found that the spreader caps were not installed with the standing rigging in the clamping hole.  Also, where the rigging was installed in the clamping hole, the end cap was not clamped to the standing rigging.  

I researched this through Selden and yacht riggers in both San Diego and Seattle (2 cities with a very experienced and vibrant maritime industry).  My research showed that the standing rigging needs to pass through the clamping hole in the shroud end caps and these clamps should be tightened.  I was a little surprised by this as I would have thought that the Catalina dealer in Ventura, CA would have commissioned the rig this way when the boat was delivered there in 2007.

So the rigger in Seattle set up the standing rig gin on my Selden rig to be clamped by the cap shrouds.  If I remember correctly, the standing rigging that is on the diagonal is routed through the clamping hole on each cap shroud.  If these is a slight vertical mis alignment, remember that this is slightly corrected for with mast prebend and a slight aft rake of the mast when it is tuned.  

Another couple of points that I found when tuning my recently restepped mast:

1.  The standing rigging cable diameter on my boat is metric sized and not inches.  Therefore, the standard C320 owners manual describing the cable sizes in inches diameter incorrect for my Selden rig.  This makes a difference for determining prestressed loads in the standing rigging, especially if you use the US units Loos Gauge's like I did.  The C320 IA tool loaner program worked great for me.

2.  I hiked up the mast and adjusted my speeders to be "level" after the mast was stepped and close to being tuned.  This way I could ensure that the standing rigging geometry and spreaders was at the correct angle to the mast ("level").

3.  Remember that the standing rigging is an indeterminant system, meaning one small change in standing rigging length can affect significant change in the stress of other rigging.  Make sure to adjust and check loads often to ensure that things are balanced and that the rig is "plumb" and "true."

4.  Make sure you check your rig tuning during and after some vigorous sailing.  

5.  I found the Selden Mast guide that came with my boat (also found on the web) to be a great guideline.

I hope this information helps.  Good luck.

Dave Swanson
2007 C320 MK II, No.  1107
S/V Emily Ann
Mukilteo, WA      

David B. Swanson, P.E., S.E.
Principal, LEED AP
Director, Structural Engineering

Reid Middleton, Inc.
(425) 741-3800 office
(425) 741-5011 direct
(425) 508-7971 mobile

www.reidmiddleton.com


On Oct 26, 2010, at 5:32 AM, "Stephen Cox" <scox at timmin.com> wrote:

> I am in the process of preparing Tegwen #1141 for a trip from Batemans Bay
> down the NSW coast and across Bass Strait to Hobart, Tasmania, then a
> circumnavigation of Tasmania and finally the return across Bass Strait and
> back to her home port of Batemans Bay.  This is a potentially "heroic" trip
> and so I am wanting everything to be as right as I can make it.
> 
> This week I had the rigging checked and tuned. (It has always been too loose
> IMHO and this proved to be the case). As part of this process it came to
> light that the end cap in the top spreader appears to have been installed
> incorrectly and I am wondering if other MKII owners with the Selden rig have
> their top spreaders configured as mine are?  
> 
> The end cap has two holes in it to take shrouds - one clamping and one with
> no grip at all.  Tegwen's cap shrouds have been installed through the no
> grip hole on the top spreader.  The Selden "HINTS AND ADVICE on rigging and
> tuning of your Seldén mast" 2010-06-29 edition talks about clamping the top
> spreader on a multi spreader rig.  
> 
> I did take pictures of as much as possible when Tegwen was being readied by
> the dealer and the detail can be seen at
> http://sgcox.site.net.au/tegwen_cap_shroud_spreader_cap.htm.  While having
> the wit to take pictures at the time I didn't have the wisdom then to
> interpret fully what now seems to be very clear.
> 
> I believe Tegwen was incorrectly rigged on delivery but just want to know
> how others have been rigged before I take this any further.  I don't need to
> lose the rig on the west coast of Tasmania!
> 
> Stephen Cox
> Tegwen #1141
> Canberra AUSTRALIA
>