Do You Wait for Slack Water?

[cal40john]

I've been noticing that all the cruising guides say you have to wait for slack water to go through pretty much any pass. As long as the current was with me and I wasn't going through at max current times, I would use the current to carry me along. I remember thinking Hole in the Wall looked too wild once and went and anchored in Octopus Islands til it slowed down. I don't remember being alone at a variety of passes when transiting with current.
I guess my issue is if all are branded dangerous in guides when some aren't then if one truly is dangerous the information is near useless.

John

[Wotname]

Originally Posted by cal40john

I've been noticing that all the cruising guides say you have to wait for slack water to go through pretty much any pass. As long as the current was with me and I wasn't going through at max current times, I would use the current to carry me along. I remember thinking Hole in the Wall looked too wild once and went and anchored in Octopus Islands til it slowed down. I don't remember being alone at a variety of passes when transiting with current.
I guess my issue is if all are branded dangerous in guides when some aren't then if one truly is dangerous the information is near useless.......

Gotta agree with our last sentence (above).
As for transiting a particular pass, I like to take the information from the said guide, apply my own rationale to it and then make a decision. In other words, the guide information is just one on many data points.

As a rule of thumb, unless there are draft constraints, I prefer to transit any pass in neaps rather than springs. If there is significant underwater obstructions, then I prefer to be going against a rising tide so that STW remains high (thus good steerage) but SOG is low (thus plenty of time to take avoiding action).

Other considerations is height of sun above the horizon and as you point out, the actual speed of current. There are times in say the Torres Straits where the tidal flow exceeds 7 knots. No way I could buck that but in general all else being equal, I prefer to go with the flow

[doug86]

Originally Posted by cal40john

I've been noticing that all the cruising guides say ..... my issue is if all are branded dangerous in guides when some aren't then if one truly is dangerous the information is near useless.

Consider the source.

They are 'guides', not verbatim rules for cruising. You have learned now to make your own decisions about passes. Good for you!

[Sunspot Baby]

Wind against current is my first concern. Even a cut that is normally easy can get down right nasty if the wind is against the current.

Then direction of the current. It's nice to ride it instead of fight it.

All this assuming adequate depth of course.

George

[Pblais]

Passes marked as dangerous usually have faster currents. The danger can come when you rely on the chart for direction. Fast current in narrow passes carve new pathways. You can know where it was but not always be certain where it really is.

The fastest currents will carry you along the outer radius of any curve and should you hang up just a bit you may become twisted and suddenly lose steerage. It means you have to power your way through to stay where you need to be. Acting like a cork floating on the water works better for corks and ducks that don't have a keel.

Going upstream for many will lower your boat speed greatly so while you are moving slow a sudden hang up or increased current and you lose boat speed and again you become twisted for a time and lose steerage. Losing steerage is to say "out of control".

It all adds up to knowing exactly where you need to be and having the boat powered enough to maintain an exact course. Without local knowledge using timid approach you could be in bad shape in only seconds. It's better to watch someone make it through rather than follow someone.

[Hotboy]

I wonder if it is safe to generalise and apply the same rationale as with crossing a bar. That is to aim at crossing 2 hours before the top of the tide?

[skipmac]

As was stated, it's hard to generalize but to me the main deciding factor is how clear, open and free from obstruction, hazards or impediments to easy transit are ahead. The concern being that going through a cut or channel with the current can make difficult or even impossible to stop if something ahead requires it.

For example, would avoid going with a strong current down a channel with a drawbridge for obvious reasons. But if there is a wide open, clear channel, no chance of rounding a corner to find a barge blocking the whole shebang or other bad surprises then riding through with the current can certainly make for a faster transit.

[Kettlewell]

I think it depends on many things. The most ridiculous example is the reversing falls at St. John, NB. Because of the 50+ foot tides there is a waterfall into the river at one state of tide and a waterfall out of the river when the tide is going the other way. There is a safe passage time in the middle of 20 minutes or so. The first time we arrived there I had been studying all the guides and tables and was waiting for just the right moment when a local boat shot by me and proceeded with the current. I thought he must know what he is doing so I followed and when we got to the falls we were definitely looking down hill, but there was no turning back at that point. We barreled down the falls in our 37-foot sailboat feeling exactly like a kayak heading down whitewater. There is a big rock near the bridge and we had to turn absolutely sideways to the current with the throttle pegged to slip around the rock, but in minutes we were swirling around in whirlpools and inside the river. So in that case, I would say follow the guides, and ignore the locals, which is exactly what I did the next time and we went through with no drama. Also, many inlets here on the East Coast are dangerous if there is a strong outgoing current and a strong incoming wind. One small inlet I use a lot has a six-foot bar right at the critical point and I have observed a Morgan OI 41 rolled right down to having its mast parallel to the water and a Grand Banks was nearly flipped over backwards in a bad sea at the bar. You have the same issue at those Pacific Coast bars.

[Tellie]

Originally Posted by Pblais

Passes marked as dangerous usually have faster currents. The danger can come when you rely on the chart for direction. Fast current in narrow passes carve new pathways. You can know where it was but not always be certain where it really is.

The fastest currents will carry you along the outer radius of any curve and should you hang up just a bit you may become twisted and suddenly lose steerage. It means you have to power your way through to stay where you need to be. Acting like a cork floating on the water works better for corks and ducks that don't have a keel.

Going upstream for many will lower your boat speed greatly so while you are moving slow a sudden hang up or increased current and you lose boat speed and again you become twisted for a time and lose steerage. Losing steerage is to say "out of control".

It all adds up to knowing exactly where you need to be and having the boat powered enough to maintain an exact course. Without local knowledge using timid approach you could be in bad shape in only seconds. It's better to watch someone make it through rather than follow someone.

Very good post Paul.

[SailFastTri]

Just to add to all of the above -- What's otherwise safe becomes dangerous when you lose control.... Unexpected loss of engine power or wind, or loss of rudder control, or getting squeezed by other vessels can reduce or eliminate your safety margin and in a constrained channel your boat will be in danger faster in swift current than slack.

That said -- BOOO! It's no different than countless driving decisions you make every time you drive a car. You've got to be your own judge of risk. The guides say it so skippers who are unfamiliar with the area can beware and make informed decisions.

[Lancerbye]

Timing is everything and all passes have their own peculiarites. I remember missing the slack by 15 min at the Yuculta rapids by Stuart Island. I had to fight all the way up until I could find some usable back eddy to get past it. I could have turned around and went back to the bay and waited for 6 hours. Sometimes being stubborn has a price tag.

[jackdale]

The guidelines I use are based on the current strength on both sides of the turn:

0-3 knots = go through anytime.

3-6 knots = 30 minutes either side of the turn.

6-9 knots = 15 minutes and getting smaller.

This does depend on the locale. I have gone through Whirlpool Rapids and Chatham Channel with stronger currents. Malibu Rapids on a strong ebb (in a powerboat) was not fun. Dent Rapids needs close attention.

[jackdale]

Originally Posted by Lancerbye

Timing is everything and all passes have their own peculiarites. I remember missing the slack by 15 min at the Yuculta rapids by Stuart Island. I had to fight all the way up until I could find some usable back eddy to get past it. I could have turned around and went back to the bay and waited for 6 hours. Sometimes being stubborn has a price tag.

Have you seen the instructions in Sailing Direction, which are also in Dreamspeaker?

I start through 60 minutes before the turn to ebb at Gillard. I hug the shore from Harbutt Point to Kelsey Point, then cut across aiming at the white house on the Sonora shore while watching the eddies. Once across I stay on the Sonora side until Gillard and straight through Gillard and Dent. This can only be done once a day in daylight. I gets me through Dent before it starts to ebb strongly.

[Capt Phil]

Spent several years towing log booms through both Hole in the Wall and the Yulcuta's around the Dent Island area and I would highly recommend talking with local commercial mariners, either fishermen or tow boat operators before attempting passage through these areas. I recall missing a tide by about 15 minutes in a 60 foot tow boat in the Yulculta's one morning and went through with the rail under and lost about three sections of logs on the rocks. This area can by particularly dangerous with deeper draft vessels like sailboats that do not have the power to get out of a sticky situation. On the other hand there are few prettier spots on earth than that one. Worth the trip but be cautious and informed... cheers, Capt Phil

[jackdale]

Capt Phil

Last April I was heading south, drifting around waiting for Dent to turn when a smallish powerboat boat come along side to check if we were OK. We said were fine, just waiting to go through Dent Rapids. He told us that he had just been through there and we did not want to do that. I responded that we did, not just now.

I have had other boats ask if they could follow us as we went through heading north. The Yucultas can be intimidating. The chart is scary, but the Sailing Directions instructions are very good. (But who has a copy on board?)