Rigging questions: Movement of mast in partners and forestay tension

[sebastiannr]

Hi there,

On my passage from the Azores to North Spain the rubber mast collar fell out of the partners. I managed to get it back in but there is still a gap between the partners and the collar, which results in about 1cm of movement of the mast in the partners fore and aft- when the boat crashes into a wave, the mast bends forward under it's own momentum. It looks like silicon was poured into the gap between the mast and the partners, that doesn't seem like a proper solution to me. It's very disconcerting to see the mast moving around in the partners like that, is it a major problem? Do I need to fabricate a wedge of some kind?

Also regarding forestay tension: in heavy weather, when most of the genoa is rolled away, there is considerable bend in the forestay despite the backstay being fully tensioned. Is this acceptable or should there not be any bend in the forestay, ever?

Many thanks,

Seb.

 

[causeway]

It sounds like you need a new forestay or backstay. My Boat is mast stepped so unfortunately I have no idea about the mast slot.

 

[30boat]

Hi there,

On my passage from the Azores to North Spain the rubber mast collar fell out of the partners. I managed to get it back in but there is still a gap between the partners and the collar, which results in about 1cm of movement of the mast in the partners fore and aft- when the boat crashes into a wave, the mast bends forward under it's own momentum. It looks like silicon was poured into the gap between the mast and the partners, that doesn't seem like a proper solution to me. It's very disconcerting to see the mast moving around in the partners like that, is it a major problem? Do I need to fabricate a wedge of some kind?

Also regarding forestay tension: in heavy weather, when most of the genoa is rolled away, there is considerable bend in the forestay despite the backstay being fully tensioned. Is this acceptable or should there not be any bend in the forestay, ever?

Many thanks,

Seb.

Rubber is not good for that application because as it compresses it moves.I know hard rubber is recommended by many professionals in the area but I much prefer shaped hardwood wedges with a shelf on top to stop them sliding down.A much better solution is a procuct called Spartite.http://www.spartite.com/Default.aspx?SiteID=3.
On my previous boat that had a keel stepped mast ,and not wanting to spend all that money, I used a hard two component silicone rubber that I found locally.I plugged the bottom part of the collar inside the cabin,placed the mast centrally in the collar with some lines around it taken to several points and poured the mix in.In about an hour it was cured and very solid.Never again did I have any problems.You must coat the mast in Vaseline so that you can slide it out later.This system provides a watertight seal but I made a boot out of a leg of an old wet suit to get further protection from sun and water.Saw the boat 16 years later and it's still there.

 

[bikedaft]

being a cheapskate and in a hurry I used hard rubber wedges ie tyre side walls cut up, avoiding the bits with ferrous metal in (prepare to be flamed, but it does work)

 

[30boat]

being a cheapskate and in a hurry I used hard rubber wedges ie tyre side walls cut up, avoiding the bits with ferrous metal in (prepare to be flamed, but it does work)

As long as it works...

 

[William_H]

Bend in the forestay is inevitable on any boat. Just how much is the real question. Assuming it is a mast head rig then you crank on the backstay to minimise the forestay sag. This however will be limited by the aount you think is too much for backstay tension. ie the hull and rig.
With a fractional rig boat the forestay tension is a function of the backstay tension but also the amount of bend the mast gets. So if you really want a bar tioght forestay then you fit running backstays to provide pull at the top of the forestay (just like a mast head rig).
So forestay will sag to leeward depending on the power in the jib. So full jib medium wind will cause as much sag as small jib lots of wind. good luck olewill

 

[michael_w]

Slack off rig.
Lubricate oversized hard rubber wedges with washing up liquid.
Grind mast forward with lines from the gooseneck area. (primary winches come in handy here)
Stuff aft chocks in.
Pull mast aft and put the forward ones in.
Below decks, fit a jumbo jubilee clip round the chocks, so they are held against the mast.
I've found a hypalon boot the best for keeping water out.

Be very wary of Spartite. I've seen a 80' Duch built ketch being lifted by her mast when the Spartite refused to part company. Lead to 2 days of attacking the Spartite with drills. Yes, the beautiful Rondal mast got rather chewed up in the process.

 

[wklein]

The two problems could be related. Keel stepped masts tend to be be more flexible sections based on them being held at deck level. If yours is not being held there its likely when you put the backstay on the mast is bending too readily and shortening the forestay height rather than tensioning the forestay. +1 for hard rubber wedges, fairy liquid and winching mast base about. Definitely wouldnt try spartight until your at your wits end with it. Problem is that unless the deck ring is perfectly fair the spartight will run into the pitting from corrosion and forms a physical bond whether or not you use vasaline. Generally it works fine but have lifted boats 6 inches out of the water trying to take the mast out. In the end we unbolt the deck ring and take the whole shooting match out.

 

[lpdsn]

You definitely need to secure a keel-stepped mast at the partners. The calculations of the strength of the rig assume it is fixed there.

Various things you can use. Hard plastic blocks, hard wood, spartite or similar. My boat only had a couple of hard wood chocks, so I made a dozen or so more from the oak frame of an old armchair.

Easiest way to do it is to take off the sails, remove the boom to avoid the load it imposes, then slacken up the rig, fit the chocks then tune as required.

Spartite can go wrong, but I race on a boat that used spartite and the rig had been out of the boat half a dozen times. The secret, I understand, is to use a few layers of masking tape before pouring in the spartite, so that there is something that will give when the mast is unstepped.