Fore-stay tension and pointing ability?

Norman_E

Norman_E

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I have lifted this quote from a post on the PBO forum about the relative merits of a Bavaria and a Legend.
Quote "I've no idea what model of Leg End it was I sailed on the Clyde once, but I was miffed that it wouldn't go upwind convincingly. The triangulated rig prevented us from getting the genoa luff to stand up straight, and so we were sailing a quite a broad angle to the headwind. " Unquote
The point seems to be that insufficient fore-stay tension reduces the ability of a boat to point close to the wind. On my own boat I have had the shroud tension increased to reduce the tendency of the leeward shrouds to go slack in certain conditions. The rigger has suggested that as my back-stay is non adjustable (and not very tight) and the bottle-screws are almost fully taken up, he should do a further job which involves shortening the fore-stay very slightly, so as to put increased tension on both the fore-stay and back-stay. I have noticed that there is some bend in the fore-stay when sailing and the boat does not point quite as high as I would like (though in general it sails well). Is increased tension in the fore-stay really likely to improve pointing ability?
 
The most important thing is to match the cut of the headsail to the sag of the forestay. A boat with a slack saggy forestay can be made to go to windward pretty well if the genoa is cut to suit.
 
In a word ... yes .... in a more complex sentence - it depends on several aspects including hull, keel, sail belly and rig tension.

A racing dinghy has highly tensioned shrouds (300lbs is quite normal), and with the shorter masts there is little noticable deflection of the forestay (quite often built into the jib these days). The tension is applied before racing and released afterwards - so most of the time the the rig is slack ( just a bungee tied to the jib halyard on my RS400 atm) ...

So - before you "tension up" your cruiser - you need to consider how much tension it will apply through the hull - it could be that you can apply more tension than you currently have without worrying...
Our cruiser deflects the forestay by about 1' in the ~30' length on a closehauled course in a F3-4.
 
Thank you. My fore-stay deflects about two feet (over a longer length than yours) in similar conditions, and subjectively the back-stay feels a bit slack now that the shrouds have been pulled tighter, so I think I will take the rigger's advice and let him do the job when I go back to Turkey. The shorter fore-stay will pull the mast forward a bit, and tensioning the back-stay will tighten things up. We did have a very good cruise from Marmaris, to Loryma, Bozburun, Datca, Simi, Rhodes and back to Marmaris with the rig as it is, and winds up to force 7, (8 at times). All the sailing was good except when we had to tack to get round the end of the Bozburun peninsula, where each tack gained us rather less than I had hoped. On the up side I certainly learned a lot about handling the boat, and "Mediterranean mooring".
 
The only problem you might get is if the mast ends up more upright it will affect the handling - noticably the weather helm as you will be moving the center of effort forwards (perhaps only marginally though?) - is it not possible just to shorten the backstay?
 
Had that thought myself, but the rigger thinks the mast is already far enough back and would benefit from being a bit more upright.
I forgot to mention in my last post that last Wednesday we sailed through one of the most violent thunderstorms I have ever seen, with huge bolts of lightning hitting the water all round us, and torrential rain. All the instruments blanked, and I ordered them turned off at the main switch panel. On turning them back on after the worst was behind us, the repeaters at the helms displayed their software version numbers, then re-booted and worked normally. It seems that some protective programming switched them off during the storm.
 
My partner was below, and could easily turn off the switches that supply power to the VDO Siemens instruments. These are routinely turned on or off that way rather than by scrolling through the menus to find a "power down" option, and the manuals state that this is acceptable practise. Restoring power turns them back on, and I have never in fact turned them on or off any other way. What was surprising was that they turned themselves off during an electrical storm, and went through a re-boot sequence I had never seen before, (including displaying software version numbers) once power was restored.
 
2 ft deflection?! You definitely need to take your riggers advice and shorten the forestay. You won't recognise your boats' upwind handling afterwards.
 
[ QUOTE ]
"Is increased tension in the fore-stay really likely to improve pointing ability?"

Damn tootin' it will. And whack some real halyard tension on it as well, when the wind pipes up.

[/ QUOTE ]

Quite right Twister.
2ft of sag is a lot.
One other way to improve pointing is rake your mast back a bit which makes me also think you should be careful you don't shorten the forestay when it might be the backstay which may need the tweak.
 
Your rigger seems to know what he's doing. The mast could have become raked too far aft by previous attempts at tightening the firestay via the backstay. In that case he is right to take wire out of the forestay.
 
I think this is the case, partly because if I flatten the mainsail by pulling the vang tackle up tight, the boom end seems to be a couple of inches too low, and I have had to move the bimini right back for clearance. I actually missed the rigger on my last day in Turkey, so the job will have to wait till I return in September.
 
[ QUOTE ]
I have lifted this quote from a post on the PBO forum about the relative merits of a Bavaria and a Legend.
Quote "I've no idea what model of Leg End it was I sailed on the Clyde once, but I was miffed that it wouldn't go upwind convincingly. The triangulated rig prevented us from getting the genoa luff to stand up straight, and so we were sailing a quite a broad angle to the headwind.



The Legend has an unusual rig c/w with most conventional boats.

With the B&R rig, tension in the rig is crucial, and a sagging genoa/jib luff will cause the bow to pay off and not allow te boat to point. With the rig properly tensioned and the sails balanced, the boat will point as high as any other.

However some owners are compromising the B&R rigs advantage and performance by fitting in-mast furling. The B&R rig is designed to carry a very powerful high roached mainsail (as developed for the Hunters Child racing yachts) as no backstay allows for all this extra canvass.

Because of the nature of in-mast furling, the sails are naturally flatter and without the roach and battens, hense loosing some of the benefits of the B&R Rig.

Obviously the In-mast makes sail handling much easier, but does compromise performance somewhat.

And this does not allow for such good pointing!

Because of the size the main, some owners tend to be a bit over canvassed at times or have sails in a little too far. With the sails freed slightly, let the speed buid and than point higher as the apparent wind moves forward.

If you have any cat sailing experience, sail a Legend in that style and you will be very pleasantly surprised.

Make the 1st reef two turns of the Genoa.

For a more conventional rig, it sounds like you have too much mast rake, so shorten the forestay, but make sure it has not stretched too far already and is getting weak, if it has been there a while, might be worth replacing rather than shortening.

Also check that the genoa has good enough halyard tension.
 
Norman

Have just looked on your profile, SO45.2 - the forestay is often saggy on these because the rig is not properly setup, especially the upper, intermediate and lower shouds, these components have more influence on forstay tension than most riggers give credit - think about it, why is the forestay a fixed length? cos its important! - upper caps should be almost at there maximum, with the rest of the rig tight - but dont just wang in on! there is aprocedure, when done test the lowers in about 20kts of wind the leeward shrouds should remain taught. I have sailed a couple of 45.2's they both had bananas as forestays, and upright masts - they give the marque a bad name. My SO43 sufferered like yours until I had a rigger "sort it out this season". They started by slackening everything off and starting from scratch, they even read the manual which was a bit scary, but now the prebend looks massive, but measurments and calculations confirm that it is correct, the forestay is tensioned and hardly moves to windward on a beat, its a different boat to sail - much improved on all points, even the french sails set better! (that is worrying) If you play a musical instrument you will know what I mean - it now "feels in tune" the boat is taught and responsive.

I would be very wary about shortening standing rigging on these rigs. IMHO there lies madness. Set it up from scratch as per the manual first - then do a lot of thinking ifs its not right.

Good luck

David
 
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