Crossing a west coast (of the US) bar at high water slack.

[Portage_Bay]

There are numerous posts on TF discussing crossing hazardous bars on the west coast. I suspect the concepts apply to any hazardous bar anywhere. Too often I see the advice to "cross at high water slack". I'll break my soap box speech down into two major chunks.

Chunk #1.
From sea timing the crossing to high water slack. Almost all of my experience is on slow boats. That means I can't speed up. I can slow down or wait. So if I time for high water slack and if I'm late, well, I'm on the ebb. Far too often on the west coast that isn't good. An outgoing tide facing an onshore wind makes it more uncomfortable and more dangerous that it needs to be. Time your crossing for 3 or more hours before high water slack and you have a bigger time window to aim for. A bit early? Slow down. But don't time your crossing for too early because the effect of the ebb can extend far out to sea and last well past slack water. The Columbia River bar is a great example of that.

Chunk #2.
Now I'll really climb up on my soap box. High water slack. There usually is no such thing. On the west coast the bigger the landward body of water the greater the time difference can be between Hi or Lo slack. Sometimes enough to get you in trouble. Use the terms and think along the lines of slack before the ebb, turn to ebb. Or slack before the flood, turn to flood. It will keep in the front of your mind that height and current timing are not the same.

Lessons learned from decades of working the west coast US. Cross a rough bar in the wrong conditions where by the time you're committed you can't turn around? Do it once, get away with it and you'll make sure you never do it again.

 

[Ken E.]

Will the worst of it usually, or always, be maximum ebb?

 

[Bmarler]

Will the worst of it usually, or always, be maximum ebb?

Typically the middle 2-4 hour span of the ebb is worst. Add in the onshore winds and it gets pretty ugly.

 

[tiltrider1]

Wind is really the bigger issue. Not saying you can ignore tides.

 

[mvweebles]

Wind against a current is a problem. On the east coast, the Gulfstream rips northbound at up to 3-4 kts and sometimes the winds are from the north. Nasty conditions.

Years ago I learned the hard way that slack water does NOT occur at high/low tide. At inlets/bars, slack water frequently lags high/low tide by 30-60 minutes or so. For example, at the Golden Gate today, currents turned from ebb to flood at 1403hrs. But low tide wasn't until 1455hrs. It's a bit of a mind game but for 52-mins from 1403 until 1455, San Francisco Bay was rising but the water was flowing outbound (ebbing).

Fast flowing water can be turbulent, but in the absence of currents in excess of 2.5-3.0 kts or so, wind-against is the big issue. On the west coast, an ebb tide in the afternoon can be tough because that's when the winds from the NW kick-up. But as @tiltrider1 suggests in the previous post, crossing a bar/inlet with 2-kts ebb and less than 15-kts of wind isn't too bad. It's slow, but not awful. As a matter of fact, 2-kts flood isn't any great shakes - slow boats can get a bit wonky with a tail current.

For the most part +/- 1-hour around slack water is usually calm enough to be more than comfortable (some exceptions - winter currents can approach 6-kts in some areas such as the GG Bridge). If there isn't wind you have more flexibility.

Peter

 

[Portage_Bay]

Will the worst of it usually, or always, be maximum ebb?

You've gotten some good input from the experienced mariner's here. It is mostly about wind against current. Much of the west coast sees afternoon on shore winds making afternoon ebbs the worst.

It stands to reason that max current will be the worst. But there have been times when I've seen the conditions worsen dramatically as soon as ebb begins. Almost like throwing a switch

Regarding the comment that some boats don't do well with a current on the stern. This brings into the considerations in planning hazardous bar crossing an intimate understanding of your boat's handling characteristics.

 

[Marco Flamingo]

As if there wasn't enough to think about when crossing the bar, then there is the moon. We are in Norway, so I just had to see the Saltstaumen maelstrom, the world's fastest tidal current near the town of Bodo (there should be a slash through the second o).

I have Navionics on my phone, so I was able to see when the "day's" maximum current occurred and book a boat to take us the 30km. Max current was at about 9pm, but given the midnight sun, it was bright out. Unfortunately, it was a waxing gibbous moon, so the current was less than 50% of the Saltstaumen maximum (23 mph). The tidal drop through the narrows was less than a meter. Maximum ebb and flood occurs during new and full moon. Then the change is over 2 meters.

Here is a National Geographic video using the same outfit we went with.

The whirl pools weren't big enough to swallow our RIB and the tongue and tailout looked surprisingly benign. Stay away from the eddies and I might even get my trawler through, although it would take 10 years off of my life. There were areas where you don't want to be and areas where you really, really don't want to be. That said, I've seen Skookumchuck (15mph) with bigger, wilder waves in the tailout. Of course, that is Skookumchuck at its worst and Salstraumen at its calmest.

We're now out in the Lofoton Islands in the town of A (there should be a circle above the A). Looking to get out to the world's "biggest" maelstrom just south of us. Moon still isn't cooperating, but should be a good show. Fools rush in where angels fear to tread.

Mark

 

[Cammacdaddy55]

There are numerous posts on TF discussing crossing hazardous bars on the west coast. I suspect the concepts apply to any hazardous bar anywhere. Too often I see the advice to "cross at high water slack". I'll break my soap box speech down into two major chunks.

Chunk #1.
From sea timing the crossing to high water slack. Almost all of my experience is on slow boats. That means I can't speed up. I can slow down or wait. So if I time for high water slack and if I'm late, well, I'm on the ebb. Far too often on the west coast that isn't good. An outgoing tide facing an onshore wind makes it more uncomfortable and more dangerous that it needs to be. Time your crossing for 3 or more hours before high water slack and you have a bigger time window to aim for. A bit early? Slow down. But don't time your crossing for too early because the effect of the ebb can extend far out to sea and last well past slack water. The Columbia River bar is a great example of that.

Chunk #2.
Now I'll really climb up on my soap box. High water slack. There usually is no such thing. On the west coast the bigger the landward body of water the greater the time difference can be between Hi or Lo slack. Sometimes enough to get you in trouble. Use the terms and think along the lines of slack before the ebb, turn to ebb. Or slack before the flood, turn to flood. It will keep in the front of your mind that height and current timing are not the same.

Lessons learned from decades of working the west coast US. Cross a rough bar in the wrong conditions where by the time you're committed you can't turn around? Do it once, get away with it and you'll make sure you never do it again.

Thank you for this guidance and information, for a novice mariner , cruising a 40' posillipo technema , 3' 10" draft. I am planning on crossing the chetco river bar at Brooking harbor , Oregon. I am not familiar and the article the post about the crossing covers mostly not flipping your boat over with getting sideways ? any experience with the Chetco river bar at the entrance to Brookings harbor ?

 

[Portage_Bay]

Thank you for this guidance and information, for a novice mariner , cruising a 40' posillipo technema , 3' 10" draft. I am planning on crossing the chetco river bar at Brooking harbor , Oregon. I am not familiar and the article the post about the crossing covers mostly not flipping your boat over with getting sideways ? any experience with the Chetco river bar at the entrance to Brookings harbor ?

I can't offer specific information based on experience crossing the Chetco bar. I'm sure there are others here on TF that can. Hoping the chime in.

In the mean time here are some resources you may find helpful

CHETCO RIVER BAR LIVE CAMERA FEED Port of Brookings
CHETCO BAR HAZARDS USCG Chetco River
Station Chetco River Includes contact info
U.S. Coast Guard Station Chetco River Facebook page