Setting up a Mast

[WoodyP]

Today my yacht made the trip by road from Grimsby where the HCA Berthmaster had kindly removed the mast for transport to Milford Haven. We got the mast up but I think I need a bit of advice on how to tension the rigging. Simple masthead, twin backstays, roller reefing, uppers and two stays each side. Never had to do it myself before as riggers replaced the rigging both times l needed it.
I don't have access to a loos gauge, so how do I check tensions. I have read about measurement of deflection, but all theoretical so personal experience is valuable. It looks pretty straight but l did get a bit of bend which I adjusted out. Unfortunately the bottle screws were not marked before they were unscrewed so I am making it up as I go. Help please.

 

[pvb]

Download this little booklet from the Selden website. It tells you how to do it, including an easy way of checking tension without a gauge.

http://www.seldenmast.com/files/1587561657/595-540-E.pdf

 

[WoodyP]

Thank you. Tired and lazy, so didn't look, relying on the helpful folks on here.

 

[pvb]

Thank you. Tired and lazy, so didn't look, relying on the helpful folks on here.

It's a bit too complicated for ordinary forum replies! It's also useful for you to print out relevant pages and take them with you to the boat.

 

[mikegunn]

Thank you. Tired and lazy, so didn't look, relying on the helpful folks on here.

It’s worth a look. I’ve just downloaded it. Thanks pvb.
Mike

 

[peter gibbs]

Do have in mind there is no perfect setting. Ensuring the mast is upright laterally is down to taking the same number of turns on the bottle screws each side. If it is half a degree out of plumb so what?

Tension is more important. Applying tension by hand until the bottle screw is hard to rotate is a good start. The shrouds should be pretty firm to the hand. Then when under sail the leeward shrouds should be no more than slightly slacker than the windward. This is for cruising rigging. Racing is something else.

Looking up the mast track will determine whether the upper stays are keeping the mast straight. again, it is not essential to remove all conceivable lateral bend in the mast - just as much as possible by eye. Rake forward / aft is a style issue. I wince to see masts so bent back that they resemble bows - useless and threatening to the rig.

Don't be tempted to remove the mast each winter - apart from all the work, it does the rig no good.

PWG.

 

[WoodyP]

I don't think many would consider a Kingfisher 30 as being a racing craft but as she is sitting level on the hard I have the chance to get things as straight up and down as I can, although she usually lists fractionally to starboard side on the water. Never managed to sort that even after distribution of heavy objects below. Thanks for thoughts , but I have heard of overtightened stays deflecting the deck, so wary of just cranking down.

 

[colind3782]

Use the mainsail halyard to check the distance to each toerail. When it's the same, the mast is upright. Otherwise, as the excellent advice above.

 

[peter gibbs]

I don't think many would consider a Kingfisher 30 as being a racing craft☺ but as she is sitting level on the hard I have the chance to get things as straight up and down as I can, although she usually lists fractionally to starboard side on the water. Never managed to sort that even after distribution of heavy objects below. Thanks for thoughts , but I have heard of overtightened stays deflecting the deck, so wary of just cranking down.

All to the good, amigo. You should check your chain stays below for integrity as a matter of good setting up practice - I don't believe the deck alone will take the strain of the rigging unaided. Boats are built to withstand quite a load and hand tightening as I described should not result in deformation. The result you seek is that stays do not go slack on the lee side when under sail - the repetitive strain and slack action is potentially damaging.

PWG

 

[johnalison]

I don't think that a small boat will come to any harm by being set up straight and moderately tight and setting out in light winds for a review under load.

 

[WoodyP]

Thanks for all the tips and advice. I know of one similar yacht that had to fit a prop between deck head and sole because the supporting arch shifted. No others have that l know about. I can't get at the chain stays to check without deconstruction, so just going to trust in that as it's not a known problem.

 

[differentroads]

The Selden booklet is really good. Its my go-to for setting up my rigging every few years.
I last did this a few weeks ago. A tip I read about somewhere - probably PBO - to check the shroud lengths are equal is to mark the shrouds with tape about 10 cm above the bottle screws, same distance from the deck on each side, and use fishing or suitcase scales to make sure the tension in the halyard that you are using is the same each side. This takes the guesswork out of allowing for stretch in the halyard. Also allow for any offset in the halyard - I was using my low stretch Spinnaker halyard which is on the port side of the mast truck and it made a difference of 10mm to the measurement of the shroud on the starboard side.

For anyone dealing with complicated rigging (I have 8 shrouds on my 10m boat), DIY re-rigging or preparing for heavy winds, I can recommend buying a rigging guage. I bought the cheapest one on the market about 10 years ago and it looks like lasting a lifetime. I don't worry too much about absolute accuracy because having equal tension in the pairs of rigging and spotting any changes over time is more important to me than the exact % of breaking strain. I once had a 60° knockdown off Lowestoft with the boat pinned over for a good five minutes with the boom end in the water while I sorted her out. The port cap shroud felt no different to the starboad one but the guage told me that it had stretched.

 

[Praxinoscope]

Hi George

Not sure if he can help but try giving Ryan (RSJ) a ring, he's local and only works in the Neyland, East Llanion area so should be fairly close for you, he has done a few bits for me over the years including bonding a steel shoe on to my previous boat, but he does a whole range of boat related stuff.
His mobile is 07785532757