NACRA 5.8 TUNING GUIDE.

[GRACELAND1216]

NACRA 5.8 TUNING GUIDE.

At the recent Nacra National Titles at Port Stephens, the top 3 places in the 5.8 fleet were dominated by N.S.W boats. As a result, I’ve decided to write a basic set up and tuning guide with the help of skippers and crews of Flat Chat (1644), Foreign Order (1591) and Yukka II (1639).

With many boats changing hands during and after the Nationals there is plenty of new and some old faces. I’d like to welcome everyone joining this friendly and very social but extremely competitive class of Nacra sailing. Hopefully this guide will assist the entire fleet to go faster which means greater competition.

At last year Nationals at Royal Queensland Yacht Squadron, Gary from Goosemarine produced some very helpful notes on tuning and setting up Nacra 5.8’s. I recommend that anyone who owns a Nacra 5.8 read and print off a copy for future reference. Click the link below to read Goose’s tips.

http://www.goosemarine.com.au/_content/documents/general/nacra%20tuning%20guide%202007.pdf

The notes below are the rig settings and tips from the top 3 N.S.W boats from this year’s Nationals. Before I go in to the settings I’ll give you the weather conditions for the 10 races we sailed.

Races 1 and 4. East 10 – 12 Knots. (lightest breeze for the series)

Races 2, 3, 5, 6, 7 and 8. East 14 -18 Knots.

Race 9. South East 18 -20 Knots.

Race 10. South East 20 – 22 Knots.

BOAT SETTINGS.

Please note.

Write down all your boat’s existing settings before changing to new settings in case that you feel that these settings don’t work for you.

MAST RAKE.

1639 and 1644. Middle of inspection port. (All 10 races)

1591 Just on the inside edge of the front of the inspection port (All 10 races). For races 9 and 10 around 20 knots, I did consider raking the mast back 1 hole on the front chainplate but didn’t. Instead, we trapezed further aft when necessary.

A couple of photos checking the mast rake.

RIG TENSION.

All 3 boats were nearly identical in rig tension, 20 on a loos guage or about 85kg hanging off a trapeze wire near the rear beam with a minimum amount of bouncing to fit clevis pin in to the side chainplate.

DIAMOND RAKE.

1639. 36mm aft rake all races.

1591. 31mm aft rake races 1 thru 8 and 39 mm aft rake for races 9 and 10.

1644. 40mm aft rake all races.

Diamond rake is measured by use a straight edge or string line across the back of diamond wires touching the spreaders and measuring the distance between the straight edge or string line and the back edge of the mast.

DIAMOND TENSION.

1639. The tightest out of the 3 boats, about 23 on the Loos gauge exempt when the wind was blowing races 9 and 10 and the tension was reduced to 5 on the Loos gauge.

1644. Firm appox 20 on the Loos gauge and not changed during the series .

1591. The loosest out of all the boats appox 17 on the Loos gauge for races 1 thru 5 and 7. Races 6, 8, 9 and 10 were sailed extremely loose at 3.5 on the Loos gauge. Diamond wire tension was changed between back to back races on the water.

BATTENS AND BATTEN TENSION.

1639. Firm tension on the battens and stiffer top 2 battens used for races 9 and 10.

1591. Firm to tight tension used for races 1 thru 8, then reduced the batten tension on all battens for races 9 and 10 to help flatten the sail.

I would have used some stiffer top 2 battens for races 9 and 10 but didn’t have any.

1644. Firm tension on the battens, battens tension not changed during the series.

Definition of Firm.

Just enough tension to remove any wrinkles along the batten pockets of the main sail.

CLEW BOARD POSITION.

All 3 boats sailed the entire series in hole 3.

CREW WEIGHT.

1644 and 1591 had the exact skipper and crew weight of 84 kg for the skipper and 75kg for crew giving a total of 159kg.

1639. Skipper 83kg and crew 87kg giving a total combined crew weight of 170kg.

MAST ROTATION.

1644. Mast allowed to float free for the entire series.

1639. Mast allowed to float free upwind all races, only used for down wind sailing.

1591. Mast allowed to float free upwind up to 14knots of wind speed than pulled on to about 070. 18 knots plus pulled on hard at 090. Down wind settings is between 070 and 090 in all wind speeds.

BARBER HAULERS.

1644. Not used at all.

1639. Only used for down wind sailing.

1591. Totally removed from boat and never to be reinstalled. It is the crew’s job to keep the head sail trimmed at all times.

JIB LUFF TENSION.

1644. Only adjustable on the beach.

1639. Adjustable from the front beam but was not adjusted during the race.

1591. Adjustable from the front beam and loosened at the windward mark and tightened at the leeward mark all races.

SAILING TIPS.

GENERAL.

Make sure that your boat is in tip top order, fill and fair any imperfections in the hull, centerboards and rudders and have the boat and fins polished. On 1591 I have sanded and faired the underneath centre seam along the bottom of both hulls to give the hulls a better finish. If your boat takes on more than 200ml of water per hull per race you need to find out where the water is entering the boat and repair it. Regular checks on internal bulkheads, the back of the centre board cases, prebend in the bridal foil and front beam, beam straps and beam bolts is also recommended. Check all fittings, hardware, rope and shock cord to make sure they are in sound and serviceable condition. Replace or fix anything which is not up to scratch.

Read your sailing instructions and ask questions at briefing in you are unsure of the courses, starts and finishes.

UPWIND SAILING.

Keep the mainsheet and headsail on hard, use the main downhaul and slowly pinch up a bit when the windward hull starts to fly a hull then ease the downhaul and slightly pull away on the helm when the windward hull touches the water. As the wind increases mast rotation can be used and easing the mainsheet and traveller a bit will help as well. Always keep looking at the mainsail and head sail tell tales to see if they are trimmed correctly. Dumping the mainsheet and pinching hard in to the wind are the last options and should only be used to save the boat from capsizing.

Boat trim is also extremely important. Crew weight needs to be shoulder to shoulder upwind and their weight should move together for fore and aft trim.

For upwind sailing on 1591 we sail with the windward rudder in the up position to reduce drag in all conditions.

DOWNWIND SAILING.

At the windward mark a lot settings need to be changed to power up the boat for the downwind leg. Release the main downhaul just before rounding. When rounding the top mark the mainsail, traveller and headsail needs to be eased and trimmed so you can accelerate quickly out of that area. Once the sails are flowing the crew needs to release the headsail downhaul, pull on the mast rotation to 070 to 090 and raise the centerboards, windward up with approximately 50mm below the hull and the leeward one approximately 1/3 to 1/2 down (mark the centerboards with a permanent marker so you know how far to pull them up). The crew than should move to the leeward side of the boat and adjust the headsail to the tell tales on the jib and adjust the slot to the angle of the boat and mainsail. The centerboards and rotation will need to be readjusted when gybing. All downwind sailing is done with the windward rudder up.

When approaching the leeward mark all the setting need to be changed for upwind sailing. The jib luff downhaul needs tightening, the rotation let off and both centerboards have to be lowered before rounding the mark. Once you are around the mark and out on trapeze beating to windward the mainsail downhaul can be adjusted to suit the conditions.

REACHING.

Unfortunately the way the courses are set these days, getting a decent reach in while racing is pretty slim. However on occasions the wing mark is set in the wrong place giving an opportunity to wind up the 5.8 for an awesome ride.

When rounding the windward mark both skipper and crew should stay on trapeze and move aft, easing the headsail, mainsail, mainsail downhaul and traveller. Than trim the sails to the new angle. The 5.8 was designed to be pushed extremely hard on reaches due to the large amount of buoyancy in the bows so don’t be scared to sheet on and enjoy one of the best rides you will ever get.

USEFUL SAILING AND WEATHER LINKS.

http://parkdaleyc.customer.netspace.net.au/documents/racing_basics_for_catamarans.pdf

www.hobiecat.com/support/pdfs/HobieU.pdf

http://game.finckh.net/indexe.htm

http://www.seabreeze.com.au/graphs/nsw4.asp

http://www.bom.gov.au/products/IDN60900.shtml

I would like to thank Ben and Graham (Flat Chat 1644); Martin and Gerald (Yukka II 1639) and Brett my crew on Foreign Order (1591) who helped me compile this information.

Written by Steve Yarrington Skipper of Foreign Order 1591.

January 2008.

[ARCAN]

Thanks Grace for the tuning guide .

Very very useful especially for a newbie like me .

Your insight into the top 5.8s is very much appreciated .

Only one thing that bugs me is crew weight .

Is there anyone who weighs in over 100 kgs ON THIER OWN ????

Mate I dump 85kgs on a good morning !

I didn't realise the 5.8 was the Lightweight cat division

Given this problem you guys have, what adjustments would you say I should make to the settings you have listed above ?

Again thanks for the guidance it is really is appreciated .

All the best ,

ANT

[This message has been edited by ARCAN (edited 18 January 2008).]

[Bradk]

Steve great information . arcan iam over 100kg in weight and only had this boat since november my crew is 94kg and we are getting the boat quicker each time we sail it .download gooses information and use it with what steve and the boys have put together and i am sure you will get quicker as well.

[GRACELAND1216]

During the last 2 months I have been experimenting with different crew weights ranging from 59kg to 106kg combined with my weight of 84kg.

Last weekend the breeze was blowing 20 - 22 knots N/E and I had a total crew weight of 190kg. The boat was the quickest I have ever felt going up wind but a different story going down wind, I could really feel the boat being bogged down.

Going back about a month ago I had a crew who weighed 59kg giving a total of 143kg in about 12 - 15 knots S/E and I found it was hard to get resonable boat speed up wind but down wind was amazing. The boat was doing the wild thing without even trying with excellent boat speed.

Another important factor is crew height, my crews ranged from 155cm to 190cm.

My theory is if all crews have equall sailing ability light crews (140kg)should do well up wind in winds to 12 knots and should be quicker down wind in most conditions except when the wind is above 20 knots.

Heavier crews (180kg +)should perform better up wind in breezes above 12 knots plus but have slower down wind speed except when the wind is above 20 knots and the light and heavy crews should be even.

[Guest Nacrajono]

Good Info Steve... Between you and goose we are starting to get a very definitive tuning guide documented which makes the class faster and faster... have to check my boat and see how it lines up with these figures.. Once again well done