Re: Spinlock rigid vang and am having difficulty with the lock/release switch.
Yes.. it's the same as mine.
If the switch 'shows' green (ie covering orange) it's acting as a boom support. If the switch is pushed to show orange (covering green) its been 'released' and is acting as a vang.
If you drop the sail with the vang in 'vang' mode then the boom will drop. If you switch to 'topping lift' first then it won't. It's supposed to self release from 'topping lift' to vang when you pull the vang tackle but mine never has.
Once engaged in the 'topping lift' mode it's a ratchet support.. if you push the boom higher you'll hear the clicks and the boom will stay where you left it. Typically you'll have to go forward and 'switch' the mode. Don't try to force it out of toppinglift mode by pulling on the vang line.
It's a neat idea in concept but it's not working as well as envisioned, they don't make it anymore.
As far as the vang goes, it should be in vang mode once the sail is up, and set to topping lift when dousing, or in very light air where the boom weight is closing the leech. The vang is less critical in normal conditions if you have good mainsheet tension when close hauled, if the traveller is eased a lot you may want some vang on then to prevent boom lift and loss of leech tension. However the vang becomes quite important when you're running deeper, there's little or no downward mainsheet pull and the vang is needed to prevent the boom from lifting, in extreme cases a lifting boom during an accidental gybe can turn into a dangerous 'goosewing gybe'....
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)