CS34 Standing Rigging

The standing rigging refers to the fixed lengths of stainless steel wire supporting the mast. Fore and aft you have the forestay and backstay. Transverse support are shrouds.

The CS34 is supported by three sets of shrouds. Those running from the masthead to the deck are called upper or cap shrouds.

The CS34 is a Masthead rig

The mast is deck-stepped with a compression pole in the main cabin of the CS34.

The CS34 has two spreaders (center image)

The CS34’s spreaders are in-line.

The shrouds are continuous rigging, meaning they are not linked/terminated at the spreaders, they run from the mast through the spreader and then continue down to the deck.

The CS34 has one cap shroud, going from the top to the deck, staying the mast against lateral loads. One intermediate shroud starting where the top spreader joins with the mast down to the deck, staying the mast against movement athwartship. One lower shroud starting at the lower spreader down to the deck.

More info:

Tuning your standing rigging

This basically means tightening up your shrouds to just the right amount of twang when you strum it like an instrument string. There’s all sorts of theories and I’m not an expert so check out some of the linked resources at the end of this page.

Make sure your mast is straight

Start by ensuring the mast is centered transversely. This can easily be done by extending a halyard down to the toerail on one side of the boat and note the length. Take the same halyard to the other side and see if it’s the same length. If it’s not straight, you have three options:

  1. Loosen the upper shroud turnbuckle on the shorter side
  2. Tighten the upper shroud turnbuckle on the longer side
  3. Loosen both upper shroud turnbuckles and start again

Now check the rake of the mast. This is the angle either forward or aft from vertical. A mast should not have forward rake. Use the main halyard and hang a weight from the end. It should settle at max 8-10″ away from the mast towards the stern of the boat. Use the forestay and backstay to adjust.

Be careful that your genoa halyard is not secured while doing this, if you tighten the backstay all of the load could be transferred from the forestay to the halyard. Unless you are trying to turn your mast into a catapult, if that’s the case, this is exactly what you want to do.

It used to scare the crap out of me adjusting the turnbuckles, thinking the mast is just going to fall over. If you are concerned, use your halyards as backups and loosely attach them to the toerail while you work.

Adjust the tension

Technically you want to tension the cap shrouds to 15-20% of the breaking load. Some sailors just go by feel, the larger shrouds are just a little bit tighter than the thinner shrouds. There are tension measuring devices that you snap on to the shroud and pull. And some people measure the amount of stretch in the cable. The last method seems to be the most scientific and accurate. But I use a tension device since the previous owner gave me his. Plus you are going to be further adjusting the tension when you are out sailing so I don’t see a need for a highly accurate tension setting at this point.

Use two wrenches to adjust. I may get some flack for this, but I like to use vice grips to clamp the top of the turnbuckle (there is a flat spot there where you would normally use a wrench). This holds to top of the turnbuckle and also holds the plastic tube protecting your sails up and out of the way. I then use a crescent wrench on the bottom part of the turnbuckle. Don’t be tempted to use a screwdriver in the middle of the turnbuckle.

Go for a sail and adjust

Look for the near perfect sailing day with steady 10 knot winds. Sail clause-hauled and sight up the luff groove of the mast to ensure it’s standing straight. The pressure from the sail could bend the middle portion of the mast if the intermediate turnbuckles are not tight enough. Tighten both windward and leeward side the same amount to re-center. Tack and check again. On both tacks check the leeward side to ensure the shrouds are not flopping around. If so, tighten both sides the same amount.

Don’t sweat it too much

As long as you don’t over tighten the shrouds, your mast is straight, the rake isn’t forward and your shrouds are not flapping about on leeward side while sailing you’re doing good. Remember, your mast is bendy so always stand back and take a look to make sure it’s not curving in a strange way. Also casually check out a few other boats in the marina and give their shrouds a light touch to get a better idea of how much tension there should be.

Resources

Hints and advice on rigging and tuning of your Selden mast, the CS34 has an Isomat mast, but this is a great read and the tuning process is exactly the same.

Also check out section 6.3 Tuning in the Google Docs owner’s manual (a work in progress)

Google Docs
North Sails