What, exactly, is a tacking angle

[AngusMcDoon]

Another reason that it is pointless is that for a constant apparent wind angle the tacking angle varies dramatically as the ratio of boatspeed to true windspeed changes. For example, if I can sail at 35 degrees to apparent wind in a 5 knot true wind at 5 knots of boats speed (boatspeed=100% true windspeed), then my tacking angle is 140 degrees. If I can sail at 10 knots boatspeed at the same apparent windangle of 35 degrees in 20 knots of true windspeed (boatspeed=50% true windspeed), my tacking angle is now 100 degrees.

When boatspeed increases as a proportion of true windspeed it's a case of diminishing returns. This is particularly apparent in multihulls and is often a cause of poor tacking angles in these boats as they sail upwind with boatspeed a higher proportion of true windspeed.

 

[VicS]

The tacking angle by definition includes lee way.

What is your definition of "tacking angle" then


If its the angle between headings, which is correct according to early replies it does not include leeway

 

[Vega1447]

What is your definition of "tacking angle" then


If its the angle between headings, which is correct according to early replies it does not include leeway

Surely angle between COG before and after tack?

Includes leeway.

Only useful as an index of boat's pointing ability if measured at slack water..

And of course varies as windspeed does...

 

[john_morris_uk]

I don't know how some people on these forums sit down as their underwear must be twisted in knots.

One might agree that in a world of pickiness VMG is a more important figure.

However I am happy to believe that the boat magazine crew sail reasonably efficiently upwind and therefore the angle gives me a rough and ready figure for measuring the close-windness of the boat they are testing.

When I raced seriously, we would steer the boat according to target boat speeds for true wind angles. In other words, for a given wind speed you either foot off (steer away from the wind) or point up to achieve the best speed for that wind. You need to modify the figures according to sea state and what is happening, but in the real world of cruising most of us just sail by the seat of our pants. I am happy to believe that the journalists sail reasonably efficiently and this gives the figure a meaning. Therefore I don't have a problem with the magazine reporting what the tacking angle is (from the compass!) as its a rough and ready measure of the boats pointing ability.

If you are lucky the journalist adds a comment about wind speed and sea state so you can make a more informed judgement.

If you are really going to buy a boat, presumably you book a test sail on a sister boat or demonstrator with the importers or manufacturers and you can make your own mind up?