There is no additional hydrodynamic force applied to a boat if it is sailing in a current than if it were sailing in a stationary body of water. There IS additional drift relative to stationary things like the shore line but this only affects our senses and our ability to get where we want to go. I'll try and think of a different way to express this....hmmm.

Yo Jake,

What your are trying to explain is explained very well and in excruciating detail here...

http://www.bartleby.com/173/18.html

Ok so we are talking about the same thing. Your right, it's all relative. The ocean could be moving at 50 knots and you wouldn't know it unless you looked at land. I wasn't quite getting the boat in bucket idea but know i see what you were trying to explain. I guess i was just trying to say is in the open water, you want to go point A to point B without leaving a straight line. Daggerboards help accomplish this by minimize side slip. In a channel, you would want to maximize side slip to help you get up the channel by letting more water flow under your hulls sideways than streaming past them. This idea only works when the wind is at your back. Does this make anymore sense? We are taking about the same thing but different aspects i think.

you're right - we have been on either side of a coin talking about two different things! However, you normally sail downwind with your boards up right? It's the same reasoning, the slip helps you get from point A to a downwind B faster*. No additional water will flow under the boat than if you were sailiing downwind, boards up, in a stationary body of water.

I was talking about another example and the site link that Jamie provided is a perfect example...modify it a little and think about an airplane: Have you ever flown on an airplane? You're at 10,000 feet and flying at 500 mph in a straight line yet you can walk around and feel no additional forces. Your boat and the current is the same thing. Your boat (you on the plane) does not feel the current moving - it only knows it's sailing as usual. The same reasoning applies to us in that we don't have to modify the way we move because the earth is spinning at 1000mph - we don't feel anything because we're on it.


*there are exceptions but that would be a whole nother' topic.

As an addition to what Jake said, Rick also has explained it to me in terms of flying an airplane. A little airplane is flying at 100 mph through the air. If it has a 25 mph tailwind, it is not flying at 125 mph and if it has a 25 mph headwind, it is not flying at 75 mph. It is always flying at 100 mph through the air. It is only in relation to the ground below that it is traveling at a different speed. So if you have a tailwind you are going to get to your destination faster and if you have a headwind, you are going to get there later.

In terms of time, if you are in the air for an hour, you will burn the same amount of fuel whether you have a headwind or a tailwind. But if you run out of fuel because of a headwind, you may end up crashing on the side of a mountain. In the case of a sailboat that runs out of wind (your fuel), you may end up crashing on the rocks on the side of a channel.

A sailboat has one option available to it that an airplane does not. A sailboat can throw out an anchor (if in shallow enough water for your length of rode), and wait for more favorable conditions.

When I was trying to get up that channel against the wind and current, I kept thinking, "I wish I had an anchor."

Jake,

Now you've started a more interesting discussion. If you are making significant leeway, that is sliding sideways while sailing downwind, then you are not going downwind as fast as you could.

I would postulate that you need LESS daggerboard while sailing downwind than upwind but that you still do not want to be making significant leeway. You need less daggerboard because of the relative vectors of the energy (lift) you are extracting from the two fluids moving relatively to one another. And from the relative speeds with which your foils are moving through those fluids.

For simplicity lets assume that your sails and boards are flat. Let's also assume that the lift off of each foil is perpendicular to the plane of the foil. While sailing upwind the forces are almost directly opposed. While sailing downwind they may be approaching 90 degrees to one another.

Also your apparent windspeed goes down, while your apparent waterspeed goes up. Thus, you need more sail area, and less board area. Upwind your apparent windspeed is up, and your apparent waterspeed is down. Thus for that reason you also need less sail area and more daggerboard area (relatively)

A couple of emperical ways to look at and think about the problem:

1.) If leeway were really good why would we reach downwind instead of just running dead downwind?

2.) Take the boards out of your 6.0. In shallow water push the boat sideways. The push it forward. It is much easier to push it forward. In the simple argument the wind is pushing it downwind. If it were faster to make leeway, that is to go slightly sideways, then wouldn't it be even faster to point your boat the way you want it to go, since there is less friction on the boat, even with a little board down going forward, than there is on the boat with it going sideways?

Another principle that you can take from this discussion and apply to racing. You need more board the lighter the conditions. In very light wind I leave my boards all the way down all the time. Ony when it blows harder do I start to bring them part way up for sailing downwind. If it's really nuken you don't even need them all the way down for upwind.

Awwww He$$. I knew I was going to start this

This could be a long one!

1) if we run dead downwind, we negate any lift generated by the sails because they would then just be huge (to borrow Rick's terminology:) barn doors. The largest reason we reach downwind is so we can achieve a degree of airflow over the sails so they can generate lift and generate 180% more force than just 'catching' air (again from Rick's videos) - right? As to why most non-planing monodulls run straight downwind when we reach; we can achieve greater hull speed than monodulls and can turn the additional 80% power into speed - hence we reach.

2) Here's an area that I admitedly haven't explored but I think I'm with you. I've often wondered if the hull speed would be greater downwind with the boards down a bit to reduce leeway but I traditionally haven't done it for some reason. I agree that moving the boat sideways is very draggy and if you were to look at the direction of a boat reaching downwind, boards up, and with a little side slip, the direction is not straight ahead but off to the side a bit. Certainly this is not the easiest way for the boat to get through the water. My question is; does the additional leeway (from totaly raising the boards) add to the total boat speed? Or does the additional drag subtract from it? I suspect the latter but am not sure.

The simple answer to "fix" your problem would be to point the boat the way it would go with the forward motion vector combined with leeway vector. Then you would be making the same course with less friction. Of course it might take a little board to get that to happen...

think of the bridge as a starting line. choose the favored side. pick a pylon that you want to pass behind, line up so you are sailing to the pylon as fast as possible, maybe on a close reach. be aware that when you get behind the pylon you will be swept toward it by the eddy behind it. bear off and foot behind the pylon and use the extra speed to shoot up into the current, as close to the pylon as you dare. trim hard and point through. speed and favored side are key, if you dont make it just ease the tiller away and drift back, wait for a better puff and try again.

ok i focused on the bridge aspect, in current try to go to the inside of the curve, the outside is where the current is faster. sailing on the inside of the bend in the current is faster, you have to choose the fastest way to the other side when you get to the point. short tacking out of the current in the eddy side of a point is good. pick a fast line to the other side when you sail past the point, get over there as fast as possible and short tack that side. the inside of the bend has less current until you get to the point.

Jamie, et. al.,

I've got alot to say about alot of this, but most of it has been said already.

Jamie, you said:Another principle that you can take from this discussion and apply to racing. You need more board the lighter the conditions. In very light wind I leave my boards all the way down all the time. Ony when it blows harder do I start to bring them part way up for sailing downwind.

I totally agree.

I still get into a 'who's right' match when I comment on what you said:
If it's really nuken you don't even need them all the way down for upwind.

I still talk to sailors that can't understand this.

Wouter once had some equations that supported this also.

One year in Ruff Rider Regatta, 2nd day, we were moving due to the current in the channel going our way. At one point I got my boat completely sideways, and stayed even with the boats in front and behind, and they were heading in the right direction. Boat in a bucket. I was heading towrd the east side, about 5ft from the bank. the others were heading down the channel, and we were all going the same speed, relative to the bank, and I was also travelling down the channel, oriented 90 degrees to the others boats, going the same speed. (PS, It wasn't a year Rick was in it)

Short-tacking along the side of a channel would be great in a Laser. With a Wave every time I tacked I think I lost everything I had gained, because I was going backward (relative to land) through the slow part of the tack. So it seemed important to limit the number of tacks.

Also, I seemed to go into irons a lot during tacks and also while parking and trying to start up from a stopped position, and I attributed this to the current effect. Rick says it was because of wind shifts. But from what somebody said above in this thread, I am wondering whether the "wind shifts" were actually because of the changes in "apparent wind" induced by current.

Anyway, I am more interested in practical approaches to dealing with current rather than theory and physics and diagrams and vectors and all that.

This is the kind of question that makes me really miss Carlton Tucker. He would have simple, understandable answers to my questions of how to deal with current in various scenarios -- in the real world, not on paper. I don't care about theory; I care about how to best get from Point A to Point B when current is involved.

Ahhhhh,... here's an explanation for your constantly going into irons. You were sailing upwind trying to beat through both the wind and the current. Suppose that the wind speed is the same as the current speed. As long as you are moving and defeating some of the current speed, you have a slight headwind. When you tack in lightish air you practically come to a stop (relative to the water) and when you stop in this current, you're moving backwards at the same speed as the wind. All of a sudden, you have no wind because the boat is moving backwards as fast as the wind is moving.

Mary,

If you can't sail faster then the current, drop the anchor.

That's all.
The rest is just a description of how I won a race doing that...

I was 17 and it was the second race in the family's new monohull (29 ft). Just after the start there was almost no wind in the Guanabara Bay, Rio. Then I noticed that all boats were moving backwards very slowly due to the tide and sent a crew member to drop the anchor in great secrecy.

It was magic: for the others it seemed that we had a private puff or something. When they found what we did, it was too late - we were leading the race. When the expected thermal headwind arrived, it helped us increase the lead to win the race with a certain ease.

But your nightmare reminded me of another race. We anchored due to the tide 100 ft from the finish line - for one hour. Not a pleasant experience.

You're right, Luiz. And Rick won a race once in a big-boat regatta because he did the same thing you did -- first to anchor and in the lead when the wind picked up enough to sail again.

As I said earlier, I sure wished I had an anchor with me; and in the future, I will definitely take one if current is going to be involved. I probably could have kedged my way up the channel faster than I sailed it. Beach cats usually are not well prepared for situations like this. At least I had a paddle, which was more than most of them had.

Here is one of the many current nightmares that we have experienced: We were on a cruising cat one time waiting for a bridge to open. The current was carrying us toward the bridge. Just as the bridge was opening, our steering system broke. We were swept through the bridge, catty-corner and bumped along the wood lining the bridge opening. Wow, what a totally out-of-control feeling that is on a big boat. The other side of the bridge we dropped anchor so we wouldn't run aground on the flats lining the channel.

Unfortunately, we did all this in full view of the local Coast Guard station, and we were immediately boarded by one group, while another group inspected the bridge to see if there was any damage that we would have to pay for. Apparently, there wasn't. All the damage was to our boat.

In my original post that started this thread, I said, "Please share your nightmares with current and tips for coping with the situation."

So far there have been only a few actual experiences shared.

Here is a question that has been bugging me for a long time. Many years ago during the Worrell 1000 one or more boats got swept into an inlet by the tidal current and ended up self-destructing against bridges.

As I recall, this happened either during a dark and cloudy night or during fog or something that prevented the sailors from realizing that they were being swept into an inlet until they hit the bridge. They could not see the land around them, so they had no way of realizing what was happening to them relative to land. And, as has been exhaustively explained, your boat does not sail any differently or feel any differently when sailed in current than when sailed without current -- so how would you know that you are being swept toward disaster if you can't see any land to give you a relative perspective?

I'm just curious whether a GPS would tell you this information or whether you don't know until you hit the rocks or the bridge or something to give you a positive perspective on the situation (like impact, or going over Niagara Falls).

A GPS would tell you if you're being dragged into an inlet. It would even tell you how quickly you're being dragged along too!

A couple of years ago I crewed on a Tornado doing the NE 100. The first day started with light air, and as we headed for the passage out of the sound we found ourselves in heavy current (the reason we went for that passage) but with little steerage due to the light winds. We thought we needed to pass a large buoy to port, but found we could make little way to that side - the current was sweeping us into the buoy faster than we could sail to the side of it. We ended up bonking it with just our port rudder with no damage, but it easily could have been worse if we hadn't managed the little bit of way we did. It was a big buoy and the current was fast. In hindsight we realized we didn't need to pass it on the port side, and we could have just pointed down with the current and enjoyed the ride. We didn't think we had time to consult the chart, but we really did. Lesson is to be more familiar (study charts ahead of time, etc.) with where you're going.

Being in situations with current I think reinforces the notion of carrying an anchor. This is heresy to some folks, but if you find yourself in a strong current taking you against your desired direction or into an obstruction, tossing an anchor out to at least hold you in place while you figure things out or get a tow would seem like a good idea. If you're making a passage, or even racing, setting the anchor and waiting for the tide to change or wind to come back is a good way to go. I believe it is allowed in racing, but you can't kedge yourself along.

Mary,

If it's about sharing nightmares, my latest ones have mostly been about being physically unable to do things that were so easy at age 20... like surviving a pitchpole or capsize without any bruise, for instance.

This (and my wife...) are the reasons why I stopped "real" catsailing and started the move to a folding tri.

But if we can include offshore sailing, then I have a couple of nightmares in one story:

Bringing a 38 ft monohull from Rio to Santos, we knew there was a front coming. It meant strong headwinds and heavy seas, but we were fully crewed and ready to race, so we set sail anyway to get arrive in time for the Santos to Rio race.

There were about 80 miles to go (out of 220) when the front reached us. The wind was at 20 to 30 kts and the waves, rain and visibility were what you would expect...

With about half this distance covered, we were heavily reefed with three hands on deck. Land was relatively close and unfortunately it was a "shallow" depth area (10 m - 30 ft).

Then I saw the ROGUE WAVE coming. I don't know its height, but it really doesn't matter. I could only shout "HOLD ON AND DON'T LOOK" to the experienced guy checking something in the mast and then make sure the helmsman was pointing to the wave.

The boat managed to climb nearly half of the "hill" and then procceded through the rest of it. The man in the mast almost couldn't hold. Due to my warning, a curious (and rather stupid) South African crew opened the companionway and the wall of water sent him violently back. We took maybe a ton of water due to his curiosity.

At the time, I couldn't help but laugh at the guy, who previously missed Salvador by 800 miles when coming from S.A. and set the clocks to Greenwich time for a 220 mile coastal delivery with no visibility. But after a minute there was nothing to laugh about.

We found that the wave somehow overloaded one of the shroud's chainplates, cracking the hull/deck. The mast was nearly useless without the shroud in that kind of weather and the deck integrity was also at risk. As usual in this cases, the engine wouldn't work, so we couldn't use the batteries to pump the water out. We almost turned back, 'cause things looked really bad and our destiny was upwind.

(Later we found that the same wave capsized a bigger boat and broke the rudder of another one - both sailing downwind from the South.)

Guided by the experienced guy, we used all halyards to help the shroud, reduced sail to storm jib and third reef and went on slowly.

Then came the second nightmare - my personal one.

Closer to Santos, close to shelted waters, I was working the waves VERY carefully with the same guys nursing the mast. We were out for hours after the wave for fear or living the boat in less capable hands.

Then we noticed what seemed to be a very small fishing boat following us and for a moment considered if they needed our help. But they kept the distance and did not signal, so we just forgot about it, concentrated in sailing.

When we reached sheltered waters the guys inside somehow managed to fire the engine, so we lowered the sails and procceeded to the yacht club, pumping the reamining water from the bilge. From outside it would seemed that we were in pretty good shape.

When we were docking the guys on the "fishing boat" approached us, so I waved at them joyfully. Then they started to shout VERY angrily at us.

It was the RC boat crewed by the Commodore himself, accompanied by his pals, who were violently and unjustly removed from the comfort of a smoking room (or something) to sail into a storm in the middle of the night, in the only available boat -to attend a distress call - from our boat!

That S.A. guy, the owner and the rest of the crew in the cabin had panicked and called the club - but didn't care to tell us outside - actually, they never stepped outside the cabin after the wave.

Anyway, the Commodore (and gang) was really angry at ME - the stupid 19 or 20 year old skipper. I just happened to be at the helm all the time they were following us, so what else could he think? He was especially angry that I didn't even acknowlege the presence of their boat after sending a distress call! And how could we send a distress call when we were able to sail AND motor all the way to the club!

It took the rest of the useful part of the night for the very experienced guy and his wife (coincidently, a sailing reporter) to finally calm the guys, tell the whole story and finally convince them that the entire deck crew (3) never knew of that radio call. Actually, only after the owner went to the restroom could she tell the real story. I could have been seriously beaten that night and almost became persona non gratta in the Santos Yacht Club...

Cheers,

The Miami-Key Largo Race finishes at the south end of Barnes Sound, and after they finish most of the boats continue on through the mangrove-lined channel called Jewfish Creek and wait for the Jewfish Creek lift bridge to open to let them through into Blackwater Sound. Just on the east side of the bridge is a more open pond area. When the current is going toward the bridge, all the boats congregate around the sides of the pond, holding onto mangroves so as to not get swept through the bridge before it opens.
One year, according to spectators, the horn blew announcing that the bridge was going to open, and a Hobie 21 apparently did not allow for the current. The boat started through when the bascule was only partway up, and the top of the mast got caught in the undercarriage of the bridge. The cat was lifted clear off the water and dangled there for a few seconds until it broke loose.