Mast Rake - Shroud Tension and Downwind

[MarkR]

Good Evening everyone,

Now I am back sailing I have been playing with the mast rake as described in the tuning guide. I have the only Supernova where I sail, an old MK1.

Now if I rake the mast back to say "Setting 4" or "Setting 5" (5900mm) as described in the guide then the shrouds get what seems incredibly loose to me. Do you really sail with the shrouds so loose, or would you normally tighten the shrouds a little when raking the mast back (which would mean doing the adjustment onshore for me)? For example with a raked mast in gusty conditions downwind, the mast is really rocking back and forth and side to side as the gusts come on and off, and if I had not checked in advance I would be afraid it was going to jump out of the mast foot.

Another question - what do you think is best for sailing dead downwind? The boat seems to go a bit faster if I head up into a very broad reach, but pacing myself against the lasers I don't think the extra speed counteracts the extra distance. I think it is better just heading straight down to the mark? Does anyone have any thoughts on this?

Many Thanks,
Mark (526)

[GavinYoung68]

Hi Mark,

Downwind, get some speed and sail as deep as possible, loose boom and if not too windy loose rig to let the boom out further, that seems to work. Unless you are pushing out to one side to get in more pressure or have some other consideration sailing deep gives better VMG.

Rig tension, well some people like to sail with a loose rig and others a tight one, does not seem to be a magic formula. In general though when the mast is in its normal upright position you should have some tension on. Using the adjustable forestay to adjust tension out on the water as a general guide don't touch concentrate on getting round the course, if you get overpowered upwind you can start to ease the rig tension, this helps the mast to bend more and depowers the rig. Keep it on tight on the reach to power up, if you have enough wind to sail the run with the boom right out you can let the rig go loose to get the boom further out and sail deeper. Word of warning though, if its windy on the run pull the rig tension back on, with no tension in the rig a capsize to windward could leave you with a bend mast. Hope this is helpful.

[MarkR]

Gavin,
Many thanks, that's helpful. I have been sailing with a rake of around 6050mm. Some time I will try reducing the rake distance and/or slackening the shrouds just a little and see how I get on, now I'm getting more used to the 6050mm setting.

[GavinYoung68]

If you want to try more rig tension with the rake still at 6050, you can go down one hole on the shrouds and pull the forestay on tighter. Having said that I use the vernier type shroud plates so I can make half hole adjustments, the standard shroud plate with just one line of holes is to.big an adjustment between each position, so I am really talking moving just half a hole down. Happy tweeeeeking

[MarkR]

Thanks, I will try adjusting the lowers as well, right now they are tight at all times. I will try loosening off a little. I have vernier adjusters on the lowers but not the main shrouds.

[GavinYoung68]

We often find that very tight lowers makes it hard to get the boat to point high, so eased forestay slackens it all of a bit and then a very tight forestay when sailing off the wind powers it all up again

[Pete1177]

Hi Mark

As Gavin suggests you can set rig tension a little higher when the rig is fully upright - maybe around 120 pounds (set with a Loos gauge). Don't go too hard on rig tension with an older Mark 1 boat. Higher rig tension will make the rig a bit tighter when fully raked. I am assuming you have a mast ramp under the mast step ?? I mostly sail at 6050mm and only slacken off a bit for downwind or upwind if it's excessively windy. Although in the last 12 months I don't think I have ever sailed fully raked back (upwind).

I have seen many boats with the wrong plates (swapped between lowers and shrouds) - even those coming from Hartleys. You want the half hole adjusters on the shrouds, so if they are the other way round, swap them over.

Definitely play around with looser lowers. You'll get better rig depowering through more mast bend at the gooseneck when you crank the kicker on. In lighter winds, looser lowers will help you to point, although in lighter wind conditions you should foot off a bit upwind for more speed rather than point too high.

Hope this all helps.

Pete Bingham
Class Secretary
SN1177

[MarkR]

Pete, Gavin,
Yes I loosened off the lowers a hole last weekend and it made a big difference to the mast bend and sail shape when I pulled on the kicker. The boat does have a mast ramp, looks like it might be a home made version but seems to do the trick and it's good and solid.
My boat does have the half hole adjusters on the lowers. However one of the full hole adjusters on the shrouds has got really bent and twisted out of shape which looks a bit iffy given the strains it probably takes, so I have bought a couple of new half hole adjusters for the shrouds. I will get them fitted next weekend hopefully.
Thanks,
Mark