Sailing with the wind right on the beam, how to go faster?

H

Heckler

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Me and mate this weekend, 46 ft Moody, sailing to windward, true wind showing 8 knots, 17 apparent. Log speed 7 - 8knots consistantly. About 50 - 60 degrees off the wind. Smashing sailing, good passage making speed. Turn around and wind is now on the beam at right angles to the boat, showing 11 knots true wind. Best speed we can do is 3.5 - 4.5 knots, didnt matter what we did.
Question. what were we doing wrong OR is that how it is?
 
It's yer apparents innit.

FWIW, in winds from 6 knots up we sail fast into the wind as the apparent increases as we increase in speed, even our 70s hull and rig will give us 5 knots or so in 6 knots of breeze. When wind on beam it stays (roughly) the same so no gain. I reckon your log is slightly over reading as you can't get an apparent that is greater than real plus boat speed.
 
I reckon the log is wrong too, depends on its location in the hull but its quite common for it to read differently on one tack than the other.

Don't forget that the True is calculated vector based on the Apparent, which is measured by the instrument, and the Speed through the water.

The tide has an impact on this too, because the apparent is a measurement of the boat through the air which is dependant on the speed through the water plus the movement of the water itself, depending on direction etc. .... innit.
 
Your numbers are not consistent, the instrument calibration must be wrong. Unfortunately you are not alone with this. Unless you have good instruments and are prepared to spend a long time calibrating them, take the numbers with a pinch of salt. Even when calibrated at one speed, there may be significant errors at other speeds.
Fastest boatspeed will be somewhere below close hauled, the more wind there is the further off close hauled generally. So if you're in a hurry downwind, get the kite up!
 
I'd be a bit disapponted with 4k in 11k true on the beam on a big boat like that. Maybe she's undercanvased, or the sails are shot.
Or you were trimmed too tight - I reckon oversheeting is the biggest killer of speed on a reach. It's easy to do especially when you've been bashing along on a beat, everything cranked in tight.
 
J
thanks for that, I tried loosing everything off, even let the main right out, thinking was that the main could act as an aerofoil parallel to the wind to suck us forward.
Chute must be the thing then to make decent passage speed
S
 
Did you move the sheet fairlead forward? Otherwise the sail will twist off towards the top and you'll loose all the drive from up high where the wind is strongest.

If white sail reaching, concentrate on getting the genny trimmed right (you might also want to let off a bit of halyard tension and let go the backstay a smidge), then trim the main to keep a parallel slot with the genny. Unless its too windy, though, a coloured sail is a better bet.
 
Thanks also, it is a cutter rig, loosened off the genny and the other one and tired it with the main as well, i understood the slot effect but nothing seemed to work. as you say. looks like a big coloured one for this point of sailing.
 
You could turn the engine on, that seems to work for most Moodys! /forums/images/graemlins/blush.gif

That apart if your wind was at 90degs apparent the true wind was from behind so you are losing power. Trimming for a lightwind reach is delicate and the tendency is to oversheet and especially to have too much kicker tension, let it off a bit and allow some twist into the main. As TK says move the genoa cars forward a tad so the genny telltales lift together, otherwise you will oversheet the genoa to stop the top lifting, that will close the slot betwixt genoa and main and strangle the airflow.

A big heavy tub like the Moody is undercanvassed in light airs, especially if it had the usual in-mast main so a cruising chute or spinnaker would be an answer if the price of diesel was a consideration. /forums/images/graemlins/smile.gif
 
On my cuttter, the following works quite well for foresail trim - trim the staysail quite a lot flatter than you think, then trim the jib as usual, adjusting the car/sheet lead if you need to (back if the bottom of the sail flaps more than the top, vice versa for vice versa). Now the staysail will probably be a bit out of whack so retrim. Then you'll probably have to tweak the jib a touch again...

The 2 foresails seem to interact in non-straightforward ways... (at least to my poor little bermudan-trained brain), so just play about with small adjustments and an eye on the boatspeed.

That said my jib is on the end of a 12ft bowsprit - YMMV.

Maybe let off a bit of halyard tension (any and all sails), to get a fuller shape. Same with clew outhaul on the main (not an option for me on my laced-foot gaff!)
 
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I reckon oversheeting is the biggest killer of speed on a reach. It's easy to do especially when you've been bashing along on a beat,

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Exactly my thoughts. You need to have the sails out further thjan you might think on a beam reach sheeted in just enough that they are drawing and no more.

Sails sheeted in too tight on a beam reach are just trying to drive you to leeward not forward.
 
There are lots of things going on here but IMO you have two issues:

Firstly – your instruments are not reading properly as the numbers don’t add up so these need adjusting. Have you allowed for TIDE? I can get your numbers to sort of work if I assume that the instruments are 1 knot out and there is 2 to 3 knots of tide running in the same direction as the true wind.

Secondly – you need to trim the sails correctly. Whilst whole books are written on sail trimming basically on a beam reach with the wind coming at 90 deg to the boat you need to move the jib’s clew outboard (try a block on the rail in your moody). You always trim your sail on the apparent wind as that is what they get.


What SOG was your GPS showing?
/forums/images/graemlins/smirk.gif
 
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ooooooo - you bitch !!! Two swipes in one post !

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Not meant to be bitchy, provocative yes!

It is a fact that there are many cruising boats that are often hailed as 'good in a blow', 'stand up to their canvas', can 'carry full sail up to F5/6' etc. This usually means that they will be undercanvassed in light winds so as the OP found will certainly be slow with a light wind abaft the beam unless they can fly a cruising chute or spinnaker. That doesn't make them bad boats, but just reflects the compromise made in the design brief. If you want to go fast in light winds you either need a good SA to displacement ratio - or more diesel, QED!
 
This is actually quite a serious problem. I am afraid that he entire hull needs replacing with something organic - like wood.
 
Why work on true wind speed ? By definition the effect on the sails and hence the speed through the water is the apparent wind. this is the breeze both you and the cloth feel. Throw away numbers from the calculated "true" instrument. Then look again at the performance of your boat.
In yesterdays light breeze on the East coast our fairly lively Elan was going through the water at 5.2 to 6.5 knots when fetching or close reaching. As soon as we bore away into Harwich Harbour the wind is aft and the speed was down to 3 or 4 knots.
I bet when your speed dropped on the beam sailing you had actually come onto a broad reach with the consequent loss in apparent wind. The boat speed is then reducing the apparent wind rather than increasing it as when close hauled.
 
[ QUOTE ]
It is a fact that there are many cruising boats that are often hailed as 'good in a blow', 'stand up to their canvas', can 'carry full sail up to F5/6' etc. This usually means that they will be undercanvassed in light winds

[/ QUOTE ] Our shorebased instructor tried that one on us during the first lessons when I said we had to start reefing in 15 knots ... till I turned round and told him he obviously didn't have enough sail if he didn't need to reef until 25knots ... /forums/images/graemlins/wink.gif
 
[ QUOTE ]
Our shorebased instructor tried that one on us during the first lessons when I said we had to start reefing in 15 knots ... till I turned round and told him he obviously didn't have enough sail if he didn't need to reef until 25knots ...

[/ QUOTE ]

I reckon with our first reef in place we have about the 'normal' middle of the road cruiser SA to displacement, that is on a 1988 vintage cruiser/racer. Then if you take a normal family cruiser and fit it with an in-mast mainsail that is also like the first reef is in place from the start, or by comparison with us two reefs. So it is hardly surprising that light air performance in such cruisers is going to be poor, because it would be like having a Ford Fiesta engine in a heavy Range Rover.

We CAN carry full sail upwind in up to 20kts (apparent) with the flattener in, everything pinned down and the traveller right off, but it is SLOW! We usually put the 1st reef in at about 16kts apparent and actually go faster more comfortably, but with our upwind boatspeed of around 7kts at 28degs apparent that means we reef upwind in just F3 true. This is why when the breeze falls light we are still sailing at a decent speed when most around us are burning diesel.

Does it matter? It depends on what you expect. We enjoy sailing in light winds, because those days are much more pleasant than the wet and windy ones and so for us having good light air performance widens the band of pleasureable windspeeds. If it is just about going from A to B then I guess it doesn't matter if the engine gets more use, each to their own.
 
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