jdoorly wrote:I've been using my mast raising system for a couple years now and I'm so pleased with it I have to chime in on this topic!
I wanted a mast raising/lowering system that:
1 could be used single-handed by a decripit old man
2 could be used on the trailer or on the water
3 would allow a hinge to be above the boom and mainsail,
4 allow storing the boom and mainsail there
5 didn't have cumbersome parts that needed to be attached
6 could be deployed in minimum time
I also wanted a bow pulpit for safety and decided to integrate the pulpit with the mast raiser if possible. Here's what I came up with, an "A" frame as part of a pulpit...
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The pulpit is made of a 7/8" dia stainless tube inside a 1" dia thinwall tube with a 1/4-20 bolt setting the length. Aluminum should work as well, and even a single 8 ft long tube could work, although mine are 9.5 ft long. The two pulpit arms are hinged just forward of the chainplates and both attach to the ends of a short tube athwartships above the bow. This tube has a 1/4-20 female connecter inside it and a bolt goes through each long tube and into the short tube and threads into the connecter. A piece of wood attaches to the short tube which protects the spinnaker from the exposed bolt heads and tube ends, and adds a bit of structure to the structure. On the outside of the short tube are two 7/8" pipe "T's" which attach to two vertical stantions. The connection of the "T's" to the stantions does not have the set-crews installed so the "A" frame (the 9.5 ft tubes and the short tube) may be easily removed from the stantions and deployed to give a leverage arm on the mast. There is a 4::1 block and tackle with a cam cleat from the short tube to the bow.
The mast hinge is not the normal Dwyer tabernackle, I destroyed two of them due to the hinge being 26" above the partners and so had to design something stronger...
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This tabarnackle retains the mast's strength and bending modality and doesn't break or bend if the mast drops by accident (but good luck with your Windex).
I have a boom gallows that receives the boom and mast when it's down (the mast sticks out over the transom quite a bit so I tie an orange PFD to the end). I've replaced the grizzled old wire cable forestay with Dyneema. I release the "A" frame purchase and stantion connections with a tug and pull it up vertical, then attach the forestay to the short tube. Pulling on the purchase raises the mast. It's about four 3' to 4' pulls, then I insert the safety bolt in the hinge which means the mast is being held up by it's step and the partners, the shrouds will tighten on a last short pull on the purchase. I let the "A" frame down and catch the stantions in the "T"'s. Done. I'd say that's about 2 minutes and just as fast to lower it.
There are several options from there: You can dial in the "A" frame connection locations and be done or you can deploy a furler or jib and release the purchase as I do when flying my UPS, otherwise I have to furl on each tack/jib.
Hi Jay - are you on the forum this winter or building more robots?
I managed to mess up my shoulder somehow this past fall, and expected it to heal over the winter but with our mountains of snow, it doesn't seem to be getting rested enough to make the progress I was hoping for. Therefore in anticipation of an eventual spring (43 days, 20 some odd hours), I'm starting to think about various alternatives for raising my mast that won't require two arms overhead (as much).
It took me a while to search and find this post where you explained your A Frame very well and I wanted to reference here to it to get it back toward the top of my stack so I could find it again over the next weeks.
1. You've mentioned you used SS tubing but you felt aluminum would work as well. Being on a freshwater lake, for weight and workability, aluminum would be my preference but I'm curious if you've had any experiences that would cause you to retract that suggestion?
2. What are you using for a block ratio for pulling the A frame down, and is it attached to your sprit, boweye, chainplate?
3. Any thoughts or problems with the A frame hinge points? Do they need special reinforcement?
Thanks for any recent experience updates if you happen to see this.
- Scott