Viper 640 Class Association Forums

Viper 640 Public Forums => Viper Discussions => Topic started by: brian partridge on September 07, 2020, 01:29:21 AM

Title: MAST CHOCKS
Post by: brian partridge on September 07, 2020, 01:29:21 AM
Hi vipers, hope everyone is hanging in there with this covid-19. hopefully some more regattas will be kicking off soon. I have a question about mast chocks sitting in the gate in front of the mast. can we only use solid inanimate removeable pieces eg, t-shaped pieces of mums favourite cutting board, or can we place something "mechanical" in there to aid in adjusting when under load?. I was thinking either a front and back piece connected by a screwdrive with a wheel in the middle, or a magic box that fits into the space in front of mast and pushes the mast back using rope purchase?
4.11 Mast chocks devices are permitted in front of the mast for the purpose of controlling mast bend at the deck: (partner blocks). The aft side of the mast may be secured in the partners with a line and cleat as supplied and positioned by the builder. Devices for controlling the position of the mast in the mast port below the deck are prohibited
Title: Re: MAST CHOCKS
Post by: Lee Shuckerow on October 10, 2021, 12:20:34 PM
Brian, this topic is pretty old but no one has replied. I wouldn?t over think the chocks, we pretty much always leave max chocks in except for extreme high wind and maybe super light wind.

If you really need help with the chock adjusting bring the keel hoisting gear and attach to the keel eye on one end and a strop or something around the mast. If you continue to add more and more chocks in breeze there is a point where this could lead to the mast breaking by causing it to invert down low.
Title: Re: MAST CHOCKS
Post by: Peter Beardsley on October 11, 2021, 11:31:11 AM
Lee: why are you guys removing some chocks in extreme high winds?  How many?
Title: Re: MAST CHOCKS
Post by: Cole Constantineau on October 11, 2021, 01:18:57 PM
I remove 0.5 inch of chocks in high winds (ie: 25+) and basically max my upper tension (~12 turns over base) to put mast prebend lower on the rig.  This helps make the overall mast structure's moment of inertia higher overall... 

There are a couple shots of the rig a couple years ago in Sarasota when we went out in 30-35kts:  https://www.youtube.com/watch?v=P_YEGwmfU3g

On Meow! we don't mess w/ chocks much aside from in those conditions.  We will pop them out if we get caught overwound on the uppers in a race where the breeze dies off...