Does anyone know the forces on the backstay; would an arch support the load? Has anyone else considered this or already done this?
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No problems here
I own an '87 C30. The backstay split was just above my head when standing behind the wheel and did not have an adjuster. I rebuilt it, moving the split up another 6', and it works great. Cost about $500 Cdn. I have seen lots of C30's with adjusters, so I made it myself, but used the same size for the cables. I had the triangle made up for me with a plate at the top. I cut the backstay and used a Sta-Lok fitting to attach to the plate. In order to attach the fiddle block I replaced the clevis pins at the bottom with twisted shackle. This avoided drilling any holes in the hull. System works great. Noticed an immediate improvement in pointing. I am not concerned anymore about the strength since I did a downwind run in 30 Knot winds (9.5 knots speed of ground with a surf) Post your email address if you want more info. Ed #4900
I own an '87 C30. The backstay split was just above my head when standing behind the wheel and did not have an adjuster. I rebuilt it, moving the split up another 6', and it works great. Cost about $500 Cdn. I have seen lots of C30's with adjusters, so I made it myself, but used the same size for the cables. I had the triangle made up for me with a plate at the top. I cut the backstay and used a Sta-Lok fitting to attach to the plate. In order to attach the fiddle block I replaced the clevis pins at the bottom with twisted shackle. This avoided drilling any holes in the hull. System works great. Noticed an immediate improvement in pointing. I am not concerned anymore about the strength since I did a downwind run in 30 Knot winds (9.5 knots speed of ground with a surf) Post your email address if you want more info. Ed #4900
Integrated Arch and Pulpit
Ed That's good input. there are two reasons for my thinking of an arch. 1) The split backstay is in a poor position as you discussed. Not only is it in the way when you are standing but also restricts you from sitting in the corner. 2) I was also thinking of replacing the stern pulpit with a more modern design (built in corner seats). I was thinking that the pulpit and the arch could be one integral unit. That way the back stay terminates at the arch, freeing up the back if the cockpit. If I know the forces being applied, I could calculate the position of the arch connections to the deck for optimum strength. I am however also interested in your approach (it may be less expensive), please provide more details. Philip.malcove@eds.com Thanks in advance
Ed That's good input. there are two reasons for my thinking of an arch. 1) The split backstay is in a poor position as you discussed. Not only is it in the way when you are standing but also restricts you from sitting in the corner. 2) I was also thinking of replacing the stern pulpit with a more modern design (built in corner seats). I was thinking that the pulpit and the arch could be one integral unit. That way the back stay terminates at the arch, freeing up the back if the cockpit. If I know the forces being applied, I could calculate the position of the arch connections to the deck for optimum strength. I am however also interested in your approach (it may be less expensive), please provide more details. Philip.malcove@eds.com Thanks in advance
Details of design
Philip You may want to post your question with the C30 email list on sailnet.com. I follow that list also, and there are some engineers in that group that could better answer your question. As for my setup, I had two 13' lengths (3/16" wire) with swaged fitting made up. Each had fork at the top end, and a threaded stud at the bottom end with a turnbuckle. Two toggles were also required to attach to the chainplates. A stainless steel plate was made up for the top of the triangle to attach the backstay and the two lower lengths. To attach the upper backstay to the triangle I used a StaLok fork (http://www.stalok.com/parts.asp?family=1xImperial) so I could make the final cut myself. As it turned out, the rigger was less than accurate with my specifications for the length of each lower stay, so I could make adjustments. When I got all components for the lower stays delivered, I assemble them and attached them to the chainplates with some string. The mast was still up. I had a buddy haul me up the backstay by halyard, and using the assembly, determined where the backstay should be cut for the StaLok fitting. I finished the work when the mast was down later on, but I am sure you could disconnect the lower part of the backstay, and cut the cable while the mast is still up. I wrapped the cutting point in a block of wood with a 1/4" hole drilled in it, and then cut the wood and cable with a hacksaw. This prevents the cable from fraying. Finally, at the bottom, instead of using the clevis pins, I used 2 twisted shacles to attach the toggles to the chainplates. I attached the fiddle block of the backstay adjuster to one of these, instead of drilling holes in the hull for a padeye. I considered using StaLoks for all fitting on the lower part, but the swaging is must cheaper. The nice thing about the StaLoks is they are better for ocean use since they are more durable. Something to consider. I am curious about this "arch". Are you talking about something like the Hunter arch used for their travelers, or something else. If you have a link that shows these, I would like to see. Good luck
Philip You may want to post your question with the C30 email list on sailnet.com. I follow that list also, and there are some engineers in that group that could better answer your question. As for my setup, I had two 13' lengths (3/16" wire) with swaged fitting made up. Each had fork at the top end, and a threaded stud at the bottom end with a turnbuckle. Two toggles were also required to attach to the chainplates. A stainless steel plate was made up for the top of the triangle to attach the backstay and the two lower lengths. To attach the upper backstay to the triangle I used a StaLok fork (http://www.stalok.com/parts.asp?family=1xImperial) so I could make the final cut myself. As it turned out, the rigger was less than accurate with my specifications for the length of each lower stay, so I could make adjustments. When I got all components for the lower stays delivered, I assemble them and attached them to the chainplates with some string. The mast was still up. I had a buddy haul me up the backstay by halyard, and using the assembly, determined where the backstay should be cut for the StaLok fitting. I finished the work when the mast was down later on, but I am sure you could disconnect the lower part of the backstay, and cut the cable while the mast is still up. I wrapped the cutting point in a block of wood with a 1/4" hole drilled in it, and then cut the wood and cable with a hacksaw. This prevents the cable from fraying. Finally, at the bottom, instead of using the clevis pins, I used 2 twisted shacles to attach the toggles to the chainplates. I attached the fiddle block of the backstay adjuster to one of these, instead of drilling holes in the hull for a padeye. I considered using StaLoks for all fitting on the lower part, but the swaging is must cheaper. The nice thing about the StaLoks is they are better for ocean use since they are more durable. Something to consider. I am curious about this "arch". Are you talking about something like the Hunter arch used for their travelers, or something else. If you have a link that shows these, I would like to see. Good luck
Concept Design
Here is a rough concept of what I have in mind (refer to the image included). The Arch will replace the stern pulpit and provide an attachment point for the backstay. The Arch might go over the full enclosure or it might be part of the support frame for a bimini/enclosure (I haven’t decided yet). This is just a virtual concept, it doesn’t exist yet. If the design doesn’t become an eye sore, I may make a physical prototype. That is why I am interested in the forces on the back stay. Phil
Here is a rough concept of what I have in mind (refer to the image included). The Arch will replace the stern pulpit and provide an attachment point for the backstay. The Arch might go over the full enclosure or it might be part of the support frame for a bimini/enclosure (I haven’t decided yet). This is just a virtual concept, it doesn’t exist yet. If the design doesn’t become an eye sore, I may make a physical prototype. That is why I am interested in the forces on the back stay. Phil
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