Well just turn around then go down the river stern first! This really
sounds like a non-problem to me. The point is you don't need boat speed,
just enough to give rudder control. The river is what is doing the work!

Cheers

Bart Senior wrote:

Well for starters, the apparent wind shift due to the "Current Wind"
(CW) would shift the Apparent Wind forward 45 degrees as soon
as you cast off. Basically, you'd have little or no flow across the
rudder when sailing with the current. Attempts at steering would tend
to put on the brakes. A close haul course would not even be towards
the dock you wanted to miss, but parallel to the shore. You'd have to
hope to gain enough speed sailing parallel to the shore to maneuver
just prior to reaching the first dock.

If you managed to get the bow past the docked boat, you still might
have to pivot the boat on it's keel with the helm to get the rest of the
boat passed the docked boat. In that case, you'd have to again get
the boat powered up again, and hope to coast around the next dock
which is a further obstacle because it extends farther out.

This is a situation of speed but no control. Chances are you would
have lost all way with respect to the current, put on the brakes with
the helm, and put yourself into the hole in the next dock. So missing
the first boat would doom you for the second obstacle.

If someone gave you a really major push off the dock with the boom,
you might clear the obstacles by sailing down with the current. This
initial push would give you some flow across the rudder, at least
initially, and give you time to get the boat trimmed for speed. You
would need to paddle hard to have any real hope to get out of there,
because the course you'd want would be the other tack. Tacking in
this situation is hopeless, unless you paddle very hard.

The smart move is to swing the boat around at the dock and sail into
the current which would give you flow across the rudder and helm
response, plus more time and room to maneuver. In this case the
apparent wind would not shift forward like the first case, but actually
shift aft as the force of the current induced wind would actually help
fill your sails!

With a strong push off the dock to counter the current the boat
would see a beam reach off the dock and with flow across the rudder,
be able to head up to maintain that apparent beam reach, while
putting some distance between the boat and the shore. Your course
over the ground (COG) would be still be backwards!

Heading upriver also gives you more precious time to clear obstacles.

"Boat wind" (BW) would be with the CW in the first case, and oppose
it in the second case. The CW would be slightly reduced but at least
working for you instead of against you.

The key to this whole problem is the effect of a dominating "Current
Wind", and to a lesser extend "Boat Wind" on "Apparent Wind". It is
easy to forget that the beam reach you see at the dock when you are
tied up, will not be there when the current sweeps you along.

What would you prefer, to try to clear objects while in irons, or to try
to clear them while moving backwards, but powered up?

Bart

"Nav" wrote


What's to stop you letting the stream take you past the obstructions
while you add minor adjustmets using the wind???

Cheers

Bart Senior wrote:


You are in a difficult docking situation. You want
to depart the dock and sail on a gorgeous day, but
must leave now. Any later and you will lose your
light, and have to cancel sailing for the day.

You docked are on a river, facing down stream.

There is a 5 knot ebb current and it is max ebb.

The wind is coming directly across the beam of your
boat and also directly across the river. It is blowing
6 knots.

The boat is an Etchells keelboat, skeg hung rudder
without a motor.

Down current are two obstacles---both are docks
that are parallel to the river. The closest dock does not
project out as far as the second but has a motorsailer
tied up pointed upriver that you must clear.

If you clear the first dock, you still have to contend
with clearing the second dock which extends even farther
out into the river. If you can't clear that dock, you are
trapped in a cul-de-sac and will collide with something,
either the inside of the dock and pilings, which are free
of boats, or else into the club house with your forestay
and likely damage your rig, if not lose it entirely.

Questions:
1. What is your strategy? What are all the factors you
need to consider in planning this departure.

2. What can you do to insure you clear both docks?

3. What are your bail out options?