The Beat and how to Point, or not as in my case..

[ChrisB]

I am relatively new to the class. I'm having a great time learning to sail the boat.

My Club have added Sprint racing to the calendar. 15 minute long pursuit style, heavily reliant on a good start, good lines and positioning at the marks.

This has highlighted an issue I have with pointing. The races are too short for me to make up ground on the other legs.

I find the Supernova to be very sensitive upwind.

I understand that it cannot point as high as a Laser, relying on speed to generate apparent wind and lift. I have found that transitions and mark rounds need to be exited low to build speed before heading up to point.

I keep the boom at or just outboard of the quarter and don't pinch. Despite this I find that I am still pointing low and slow on the course.

I can find speed by heading lower with the boom a handbreadth outboard, but this takes me even further away from those I'm racing.

I haven't sailed with another Supernova so I don't know how high I should expect to point, or whether there is a sail setting I am missing.

Any advice would be much appreciated.

[Pete1177]

Hi Chris,

Since you have my old boat 1068 I think I owe you a reply. 1068 was set up well when I had it and was both fast and easy to point. It may have been re-tuned when Frank McMullen had it though or subsequently by Hartley's. Assuming you haven't drastically altered things it's difficult to know what's going wrong but you are correct in saying you need boat speed to point well, so it pays to foot off a little and generate boat speed before you aim high. Crucial to all of this is to keep the boat flat as with any heel you'll be correcting weather helm with the rudder and taking a little off the speed. Upwind is where it counts as you spend more time going upwind and places are easily lost upwind.

You should be able to point as high as lasers if things are set up correctly.

Have you checked the windward telltales are streaming correctly for fastest speed when going upwind (i.e. not stalling or trailing upwards but streaming straight back or up slightly at say 10 to 20 degrees).

The other thing I would check is that your leech is not closed off by too much kicker or mainsheet tension, but as you are not close to centre line with your boom then this isn't likely.

You could try adding some Cunningham upwind, even in light winds. If the sail is old then Cunningham will bring draft forward and could improve power/speed especially with standard battens (not tapered) and older cloth. Worth trying to see if it helps.

I find that to point well you need good boat speed and the boom in between outboard and centreline. The windward tell tales will be streaming upwards at 45 degrees or higher. In medium winds you should be hiking hard to keep the boat flat.

To be honest it's a process of elimination which will take time on the water. You really need another competent Supernova to test one-on-one sailing against.

If you are really stuck then you could come to the Bowmoor open on 24th July - we are thinking of having a small training group on the Friday so you could participate in that and camp overnight for the Open on the Saturday. We can do one-on-one sailing so you can fix the problem.

Hope that helps & maybe someone from the Gold fleet can offer their advice.

Pete
SN1177

[ChrisB]

Hello Pete,

Thank you for getting back to me.

1068 is a beautiful boat. I'm really enjoying the Supernova. I have no doubt the issues I'm having are of my own making.

The time I have spent sailing this last 7 weeks has been the first opportunity I have had since buying the boat to get to know her. I'm very happy, but aware that I have a lot to learn.I would like to attend the training day. Unfortunately I need to return to work on June 27th. I will be overseas for 8 weeks.

I have spent the weekend watching Supernova videos on YouTube. Sunday was racing, again the Sprint format that has highlighted my issues with pointing.

I did better this time finding more speed, but still suffering from poor height heading up.

Your point about use of Cunningham is a good one. I am using an old sail which I have refreshed with tapered battens. Despite this the draught of the sail is 60 to 70% aft of the luff. I find that when I bring the boom inboard of the aft quarter the boat stalls.

I will see what the Cunningham can do to pull this forward next time I sail. I will also check my mast rake settings and fore stay marks are correct.

It is possible the sail is blown. I have a new one that I can compare it to. Swap them out and see how this changes how the boat moves.

I will check the Supernova Calendar for training days and open events to get involved with next time home. Bolton SC isn't far from me. I'll ask if I can join them for part of their race program.

Thanks again for your time.

[Pete1177]

Hi Chris,

If the maximum draft is 60-70% back then you definitely have a problem with the sail and if you are using tapered battens this should help to bring the draft forward to about 45%. Have you actually measured the camber with the boat rigged, sail set and the boat tipped on it's side (the mast end needs to be supported on a trestle or something to hand in the dinghy park)?

If the boat stalls when you are inboard of the back quarter then you are losing wind attachment on the sail. The leeward tell tales will be dropping and your boat speed will reduce. This almost certainly indicates a significant problem with sail shape. Also worth checking when using Dynaflex tapered battens then substitute standard non tapered battens for the top 2. I have found that this is the best configuration in most conditions except in the very lightest airs.

I have a picture of 1068 rigged with a Jeckells sail taken in December 2016. This is with standard battens and you can see that the draft is about right (45 - 50%). If you can email me a similar picture then I will have a look.

IMG_1178 small.jpg (63.58 KiB) Viewed 14507 times

So the first thing I would do is re-check the sail and swap it for a good one. If the sail is old then the bolt rope will have shrunk possibly by as much as 100mm. You can compare 2 sails by laying one on top of another and this will tell you if the luff is short. In that case you will definitely have to use significant Cunningham to pull the draft forward.

Please let us know how you get on.

Pete
SN1177

[Tony1246]

Hi Chris,

I've replied to your message to me but basically bring it to Bolton and we'll have a look at it. We regularly have over 12 novas racing of all levels of experience.. Frank, the previous owner, is there as well. You can join the races and we can have a look at how you're going.
You'll enjoy it and there's plenty of experience to get you on the right track

[ChrisB]

I've changed out my sail. Big difference in length (ref attached photo.)

Old Sail n2.jpg (70.37 KiB) Viewed 14148 times

Notable difference in size.

Old Sail n1.jpg (80.08 KiB) Viewed 14148 times

I then measured my mast rake at the four settings I use to confirm they were as originally set.
Top of the mast to the top edge of the upper rudder pintle. 610 / 605 / 600 / 595

I sailed the boat yesterday. Felt great and I seemed to point well.

We'll see how I go at my first race..

[Pete1177]

Chris

I don't think it's any surprise that the bolt rope on the old sail has shrunk (by about 7 inches by the look of it, which is a lot). This sail might be the original 1068 sail. The good news is that it still has a bit of bolt rope extension so you can unpick the stitching and pull the sail cloth down and restitch. This will correct some of the shortness. Unfortunately Hartley's seem to be supplying sails with the bolt rope cropped (as in your new sail) so this isn't possible on that one in the future. You can unpick and stitch a bolt rope extension on as I have done on a previous sail - it's a relatively easy DIY job.

Maybe we should get Hartleys to start supplying sails with the bolt rope extended by 6 inches. If I was buying a new sail then I would specifically ask for this and reject any sails that have a cropped bolt rope. I'll take this up with Gavin.

It's wise to periodically hoist the sail and wind on max Cunningham when you can (on light wind days to stop the sail flogging too much). This might help to keep the bolt rope stretched. I believe the mechanism which causes bolt rope shrinking is the repeated tightening and loosening caused by hoisting the sail and tensioning the halyard.

I would be happier if Jeckells could find a different bolt rope material that doesn't shrink. After all, £900 for a new sail that has an inherent defect is a bit rich!

Best regards
Pete

[ChrisB]

First race with the new sail.

I can now point. Which is a relief.

Next step is to work out how to get the best out of the boat. I was inconsistent during the race. I did better on some points of sail than others. I suspect that some of this will be down to poor technique, trying to make the Supernova act like a Laser, or behave like a Solo (the majority of the boats I sail against). My main issues are a loss of speed through transitions, I'm slow upwind (pointing is under development), and poor race craft.

My home water is a reservoir surrounded by embankments and trees. The wind is somewhat eratic. I need to work on boat handling to improve performance in semi-automatic, so I can look ahead a little more. A lot more time in the boat is called for I think.

With regards to the sail, I have started to bring the sail home with me after every race to store in my dark, cool, garage rather than leave under the boat cover until the next race. Maybe the sail was cooking under the cover in the warmer weather?

What is the thinking with the use of tapered battens with a new sail? My new sail came with the standard battens installed. I am considering installing the tapered battens from my old sail in the new. I would expect this to help support and maintain the cut of the sail and the sail shape. If I am correct this should help keep the sail in good condition longer.

How will this affect sail performance?

Chris

[Pete1177]

Hi Chris
It seems that you now have the boat set up more or less correctly and that the sail was the main issue with pointing.

If you are generally slow upwind then then make sure you keep the boat flat to stop weather helm and lean body weight forward in the lighter winds to increase waterline length.

The trees and embankments are a common problem for inland waters. The biggest problem is spotting short term wind shifts and wind holes and localised pressure changes as the wind swings over and around obstacles. This is where you need fast reactions so weaknesses in boat handling will be more evident. Fast tacking is a key skill upwind.

Definitely don't store your sails or foils in the boat - take it home and they won't be stolen hopefully. Roll the sail up dry not wet. Taking it to a cool dark garage is OK but it won't stop the bolt rope shrinking. I have stored my sails in a sail store for many years but they still shrink. The bolt rope shrinking is a common problem and this, in combination with mylar film stretch, causes the draft of the sail to move aft in old sails. The way to correct this is to both reset the sail luff to the correct length to take out the shrinkage and to force a correct draft in the sail by using tapered battens.

The tapered battens in a new sail won't do much for the performance unless you want better gust control in the stronger winds. On new cloth, the sail cut on its own will force a good sail shape. It's only where you have old, worn mylar that the tapered battens will give a much nicer sail shape. In any event, sail with the two top battens untapered as a general rule as you don't want the draft too far forward at the top.

Pete

[Pete1177]

To add to this, I'm having a look at the sail shape issue with older sails hoping to publish a simple DIY guide to correcting old sails (particularly the Jeckells sails which don't last very well). This will help those who cannot afford the £900 for a new sail so still sailing with their old saggy ones.

Pete
Class Secretary
SN1177