Wind Against Current WTF?

[Delancey]

Well, tide changed a couple hours ago.

Boat is lying bow to about 3 knots of current now. 8 to 10 knots of breeze coming from 180 degrees opposite direction of the current. Meanwhile, anchor rode is sticking out 90 degrees sideways directly abeam. Boat is fixed, not tacking with moderate tension on the rode.

I know it should make some sense but to my small mind it doesn't.

Further, half the time I drop the hook in a wind against current situation I end up sitting somewhere completely different than where I thought I would.

I mean, I am at least vaguely cognizant when it come to judging winds speeds and guessing at strength of currents. I get it that the underwater profile might matter more than windage. Sure, look at the way other boats are laying. Whatever.

Any you salt-encrusted sailors out there care to share your wisdom on knowing where you will end up when you drop the hook in these contradicting situations?

[a64pilot]

Boats are different, mine often lays 90 degrees to the wind, I can be on a mooring ball, and every boat in the mooring field is pointing into the wind, except mine, she will lay sideways to it, and often will sail past the morning ball dragging it into the hull.

[JPA Cate]

Catamarans tend to lie to the wind. Even fin keel boats tend to lie to the current, especially at max flow. If the multihull (goes for tris, too) want to lie with the monos, deploying a small drogue off the stern will help them to do so.

If it's slack water, the mono will lie to the wind. If the current is much less, you'll always lie somewhere different from where you will when they're in alignment. Makes judging the swinging circle way more challenging to me!

Ann

[belizesailor]

Delancey, what kind of boat do have?

As posted, the specifics of the boat make all the difference.

Yours is answering to the current so likely it has some sort of keel...right? By contrast, dagger board boats answer more to wind than current.

Example, I once found myself bumping sterns with friends anchored nearby. My cat has mini keels. Theirs had dagger boards. Wind and current were opposed 180d. My boat answered to the current...theirs to wind...bump!

[Delancey]

Mine is a forty foot mono, fin keel with detached spade.

Look, I get the general concepts. All I am saying is half the time I come in and anchor in this situation, I end up in a different spot than I expected, despite the fact that I get the general concepts. Wind and no current or vice versa, I drop the hook, fall back, and end up precisely where I anticipated. No problems.

Wind plus current? For me it's usually a crap shoot. I can't be the only one am I?

[Reefmagnet]

Yep, force of current on the keel vs force of wind on the topsides. Then throw in hydrodynamics and aerodynamics. I've got video of my mooring ball being suck under the boat midships and being spat out the other side, only to repeat again a short while later.

And to add to how the boat is lying; Worry also about how the dinghy always seems to manage to t-bone the mother ship on a regular basis in these kind of conditions.

[svHyLyte]

An old retired Ship's Pilot friend of ours once explained the difference between "boats" and "ships" to me. "Boats" swing to the wind while "ships" swing to the sea. The position of your "Boat" (or ship) relative to your ground tackle will often, if not always, be directed by the current flowing through your anchorage, if any. On the other hand, your "Boat's" heading (i.e. the direction the bow points), will often be dictated by the windage of your topsides/rigging. Accordingly, a "fat" furled" headsail may cause your bow to veer to the left or right of the anchor rode. A "riding sail" is usually effective at minimizing if not preventing the effect.

FWIW...

[thomm225]

It's just current vs wind.

Sounds like you are used to less current than you are now getting.

If your CQR is dug in good, you'll be fine

[sailorboy1]

I find it takes a lot of wind to overcome 2.5kn of current. Otherwise it's point into the current and the wind on beam. The end sucky result is that there isn't a breeze through the boat

[belizesailor]

Originally Posted by Delancey

Mine is a forty foot mono, fin keel with detached spade.

Look, I get the general concepts. All I am saying is half the time I come in and anchor in this situation, I end up in a different spot than I expected, despite the fact that I get the general concepts. Wind and no current or vice versa, I drop the hook, fall back, and end up precisely where I anticipated. No problems.

Wind plus current? For me it's usually a crap shoot. I can't be the only one am I?

Yeah, thats really tough to call in advance because the variables involved are significant. Even small changes in speed or direction of wind/current could make a signficant difference.

I just use an "empirical" approach...drop the hook and watch what happens. If I dont like it, I move. Of course that doesn't deal with the late night current/wind shift.

So, no you are not alone...its a crap shoot. [emoji41]

[Delancey]

Sitting here in this particular spot over the past several hours, same wind, same current, every now and then the boat turns ninety degrees to the current/wind, drifts a bit, then jerks at the rode before turning back and drifting to where's it was before.

Nothing changing, no wild eddies, can see bubbles in the water drifting by the same as always. Can see my movement between the beach on shore and the range marker on the other side of the boat. Strange.

[belizesailor]

Narrow fin keels do tend to sail around quite a lot. My Hobie 33 sails all over the bay at anchor.

And cats can do really strange things when wind and current are oppossed. I sat at a resturant ashore once and watched my cat in light opposed wind and current. It would answer directly bow to current...thus presenting the windage of stern and deckhouse aft bulkhead to the wind. The wind would slowly win out over the current and the boat would slowly move forward over the anchor rode...until it ran out of rode...then it would stop, spin stern to current and start to drift back down over the rode....until it ran out of rode again....stop, spin stern back into current and start all over again. I watched it do this for about an hour.

[StuM]

Originally Posted by Delancey

Wind plus current? For me it's usually a crap shoot. I can't be the only one am I?

Only when they are coming from different directions
And no, you are certainly ot the only one.

In summary, it depends on 5 factors:

1. Your windage (which can be a complex issue of where the centre of effort of the wind on the hull and superstructure ends up in a crosswind)
2. Your underwater profile
3. Wind speed
4. Current speed.
5. Relative direction of wind and current.

Relatively minor changes in any of 3,4 or 5 can have a major effect on how you lie.

[Mike OReilly]

No wisdom to offer (at all), but just have to add I'm quickly being educated in all you say. We're making our way out the St. Lawrence from the Great Lakes and having to cope with currents and tides for the first time in many years.

Right now I am swinging anchored in 2 knot current with 10 knot wind behind me. We are sort of hanging bow to current, but with chain 90% off the stbrd bow. Holding fine, barely moving, but weird.

I find it hard to judge which way to set the anchor just from knowing wind and current

[JPA Cate]

Mike,

I'd guess, with your keel shape, that you will tend to lie more to the current than the breezes.

Our boat and yours are very different shapes under water, but we often anchor going up current. When wind and current are opposed, anchoring upwind will always have the boat searching for a happy medium. In our case, our bow has little bite in the water, and we have the two furled headsails' windage to help us lie to the wind--heh heh--but the current usually is the driver till the wind gets up, and if from astern, the windage pushes up over the anchor, sometimes all the way to the other end of the chain. Nuisance! and not too fond of grinding the chain into the bottom paint. Where possible, we try an avoid such anchorages, but of course geography and wind are as they are. What's a poor sailor to do?