Sat Mar 7th Deception Pass (almost)!

Tell us your tale of coming nose-to-nose with a 6 gill [--this big--], or about your vacation to turquoise warm waters. Share your adventures here!
Post Reply
User avatar
pensacoladiver
I've Got Gills
Posts: 1350
Joined: Tue Aug 26, 2008 5:00 pm

Sat Mar 7th Deception Pass (almost)!

Post by pensacoladiver »

Last week, the stars were lining up good for a Deception Pass dive on Saturday...

1. Wife was willing to drive the boat.
2. Decent slack period with minimal water exchange between flood and ebb tide
3. Dive buddy was in town.

Of course as the week progressed, I noticed the marine forecast was getting worse and worse. We had planned on a 0600 go from Cornet Bay (about 1/2 a mile from the pass). I didn't sleep at all Friday night as I was up checking the wind every 30 minutes. At 0500 Saturday, there was no wind at all at my place. I figured we could do one dive and be back before any hell broke loose. Got to the boat ramp and all was looking good. Sure enough, the miuye the boat hit the water, winds picked up out of nowhere to at least 25 knots. By the time we got to the pass, there were 3 foot waves there.

We actually found some decent shelter on the northeast side of the pass, but the wind was enough that I was not going to leave my wife fighitng with the boat while I was underewater... Back to the boat ramp.

We decided we were going diving somewhere. So, I drag the boat to Skyline (already halfway there, why bother taking it home). Skyline was pretty well protected, so we left the boat in the parking lot and did a shore dive.

My buddy absolutely HAS to go to 100 feet if given the chance. That's where we went. At about the 85 foot mark, there are 2 cutout areas in the rocks that house a good number of Rockfish and an even better number of Kelp Greenling. On our way back in from 100 feet, we managed to navigate right into said cutouts. Saw several good sized Kelp Greenling which made me regret not bringing my gun (live and learn).

We have also had good luck spotting GPO's there and Saturday was no exception. Saw the biggest one there yet at about 30 feet. He almost came out to play but the decided better of it.

To add to the discussion of tides at Skyline, we were diving right between ebb and flood tide that day with about 3 inches of water movement bewteen the 2. We had absolutely zero current to deal with. It was the most relaxing of my 15 plus dives I have done at Skyline. The pain in the a*$ came when we got back closer to our exit point. The wave action was just enough that we had to time our kicks with the incoming waves. There was enough of an outwash to stop all forward movement... it was actually kind of fun though.

Chad
User avatar
whatevah
Aquanaut
Posts: 665
Joined: Thu Jan 03, 2008 12:54 am

Re: Sat Mar 7th Deception Pass (almost)!

Post by whatevah »

Sorry your plans didn't come together (though choosing such a good day for Skyline Wall was a commendable recovery). Some input for next time: visibility in Deception Pass is notably worse during the ebb, so it is best to target a high slack rather than the low slack you'd chosen. Also, the slack you'd chosen was not very good - the dive would not have lasted long enough to be worth your trouble. The high slack later in the day would've lasted long enough for a fairly short but worthwhile dive perhaps, and the visibility would've been much better.
“When one tugs at a single thing in nature, he finds it attached to the rest of the world.” -- John Muir
User avatar
LCF
I've Got Gills
Posts: 5697
Joined: Tue May 30, 2006 5:05 pm

Re: Sat Mar 7th Deception Pass (almost)!

Post by LCF »

Please pardon the hijack, but I have a question. I assume a "high slack" is a slack after flood. I looked at the current predictions for Saturday, and I can't figure out at all how I would know how long a slack would last, or why the low slack would be shorter than the high slack. Can somebody enlighten me? If this is something Mischi teaches in her class, I'm fine with being told to go take it.
"Sometimes, when your world is going sideways, the second best thing to everything working out right, is knowing you are loved..." ljjames
User avatar
pensacoladiver
I've Got Gills
Posts: 1350
Joined: Tue Aug 26, 2008 5:00 pm

Re: Sat Mar 7th Deception Pass (almost)!

Post by pensacoladiver »

Whatevah,

As I was coming back across the pass early morning, I realized a few of my misconceptions. I saw that flood was a 6.8 and ebb was a 6.4 (or something along those lines) over a 5 hour period. I figured with only 3 inches of water moving, we could dive the whole time between ebb and flood. I WAS WRONG. lol As I came back across the bridge, I noticed the current was pretty strong. I suppose 3 inches of water is not a big deal in the sound, but going thru the pass, it is not something I would want to be diving in.
User avatar
fmerkel
I've Got Gills
Posts: 1037
Joined: Mon Jan 12, 2009 6:45 pm

Re: Sat Mar 7th Deception Pass (almost)!

Post by fmerkel »

Curious. What are you using for data? I use Tides and Currents 1.05. I'm not finding anything that gives me the data you refer to. I've only got 2 dives at Deception (shore) on extremely low exchanges so am interested in how to decide when to go there. Since I'm shore based that's not a day I would have thought a good one.

Similar for Skyline. I do have some experience with standard exchanges that work but I've had a couple of swims.
What time did you dive? On exchanges that look kind of like that Sat. I've had persistent outgoing current. I dove them on the usual 30" before slack before ebb. Not sure if slack is earlier or later or maybe it's potluck on really low exchanges.

Whatevah seems to know the terrain up there. We had a discussion going about Skyline but it was admittedly in the wrong thread and needed to move. This thread seems to deal with both locations. Can we utilize it?

Fritz
To Air is Human,
To Respire, Divine.
User avatar
whatevah
Aquanaut
Posts: 665
Joined: Thu Jan 03, 2008 12:54 am

Re: Sat Mar 7th Deception Pass (almost)!

Post by whatevah »

LCF - I've heard good things about Mischi's class and I know that what I've learned about tides and currents has helped me to get the best out of the available conditions, but I've never actually taken a class on the subject. I learned from a most excellent diving/boating adventurer friend, and he uses the phrases "high slack" for the slack which ends a flood and "low slack" for a slack which ends an ebb. So now I use the same phrases :) My experience has usually been that the flood brings cleaner, clearer water from the straits, while the ebb is draining the silty water that flows out of the rivers. Some places (like the south sound and especially Hood Canal) have less flow, less mixing, and more layering I have noticed. So even on an ebb you often see a distinct layer of mucky water on top with much better visibility below. In the straits, Admiralty Inlet, the San Juans, etc, the current tends to mix the water more. Deception Pass is the extreme - I've had dives there where the visibility was easily 35 to 40 feet during the last part of the ebb - then the current switches direction and the visibility can drop to 8 feet in a minute or two - the Skagit River spews a lot of silt in late spring and late fall.

As to the length of a slack, it depends on your comfort level and your goals for the dive. I've noticed that divers' perception of the amplitude of current varies wildly - understandably, because most people have to make a guesstimate based on past experience. I read somewhere that an olympic class swimmer in warm water SCUBA gear can briefly maintain a rate of 2 knots. For the rest of us, in cold water gear, 1 knot is a lot of current. Upwards of 4 knots, the current is enough to operate the purge button on some 2nd stages (causing freeflow) when you face into the current. If you turn your head sideways it will try to slide your mask around your head so the nose pocket is by your ear, and it may overwhelm the exhaust valve on the 2nd stage so you're breathing wet air. If you are planning a drift dive in laminar flow and you can see where you're going, an honest 1.5 knots might be fun. If you want to stop and take photos, you will probably want something less than 0.25 knots. It is interesting to participate in group dives and in the interim take a quick survey of estimated rate of flow. I have found that people will typically overestimate by a large margin.

Chad - Deception Pass is one of those wacky places to plan around. You've probably seen the pattern around these parts - floods bring water flooding in through the Strait of Juan de Fuca. The floods are generally pushing water in from the west to the east - squishing to the south through Admiralty Inlet and to the north through Rosario Strait and the San Juans. The ebbs are the reverse of course. Deception Pass is a link between two bodies of water - one which is at the same place in the tidal pattern as mid Rosario, and the other (down by Possession Point and Point No Point) which is the south end of Admiralty Inlet. They're offset by quite a bit of time, and Deception Pass is the equalizer - it doesn't follow what you'd see predicted for Rosario Strait or Admiralty Inlet. It is also affected by the significant flow of fresh water out of the Skagit River. In addition, wind from the west will cause slack to arrive earlier or later than predicted in Deception Pass, as all that water pushed by the wind hits the bottleneck.

Fritz - I often use the same software - Tides and Currents. You should see a button to enable a "table" view in addition to the obvious graphical view - very handy I've found, and it will show you the raw numbers that I refer to.

I have come up with a set of rules that I use in devising good days for Deception Pass and for Skyline Wall. There are probably dive plans which work fine and don't comply with my rules, but I'm happy with my system, because it has always worked for me. If the day I'm looking at doesn't fit my pattern for Deception Pass, I'll dive somewhere else (pinnacles in Rosario Strait, or walls in the San Juans).

What I do for Deception Pass is this: I look at high slacks - so I'm diving the flood which is slowing, then there is a brief moment of stillness, followed by a growing ebb. I look at the time of day that the flood has slowed to 1 knot, and then the time of day when the following ebb has built to 1 knot. I've dove there on days when there is over 40 minutes in that period (happens once or twice every few years), and I've dove days when it was more like 10 minutes. I've managed a 70+ minute dive on one of those 40 minute slack period days, and on a 10 minute slack period day I've managed something more like 18 minutes (but that was also the only time I've ever been spun end for end by current). Saturday's low slack (early AM) was around 13 minutes long by this method of estimation, and the later high slack was around 17 minutes. If I'm trying to maximize my time for the dive, I'll get in the water when the program estimates that the flood has slowed to 1.2 knots. At this stage of the game, there is no realistic way to hold position in the current - you are drifting. You can stop by grabbing hold of a rock, but if you have a camera you will really be struggling to hold it still enough in the other hand to get the focus to lock. If visibility is good you can turn your head to look behind you and check for the next rock that you want to zip to. If you don't have this software, you can use the regular current prediction tables provided by NOAA to find the time of the high slack in Deception Pass. Then you can look at the magnitude of the preceding flood - the best days are those when that value is much smaller than average.

For shorediving Skyline Wall, I am again looking at high slacks - this is because I want to ride the flooding current from the entry at the beach west to the wall, enjoy the slack, and then ride the ebb to the east and back to the exit. Burrows Pass is a site where the direction of flow defies the general pattern (because it too links two large bodies of water). My own experience has lead me to believe that the magnitude of the flood is not critical, but the following ebb must peak at 1 knot or greater if I want a good reliable return ride sometime close to the time I'm expecting it. When I reach the site, I watch the kelp bed at the corner of the wall - when it pops to the surface I figure it is about time to get in the water.

So - those are my formulae. I'm glad to see some discussion and would appreciate more data points.
“When one tugs at a single thing in nature, he finds it attached to the rest of the world.” -- John Muir
User avatar
pensacoladiver
I've Got Gills
Posts: 1350
Joined: Tue Aug 26, 2008 5:00 pm

Re: Sat Mar 7th Deception Pass (almost)!

Post by pensacoladiver »

Awesome post. Thanks for the info.

I use http://www.saltwatertides.com/pickpred.html to see when the floods and ebbs are. Granted, it does not have current values. I suppose I should dtart to learn the current method also.

I hae dove Skyline when there is a pretty strong ebb (pushing against me on the way out) and I was thinking "man does this suck", but after I got my breath back at the kelp beds, I just kinda rock crawled out to where I wanted to be and then enjoyed the ride back in.

I've done the same thing at Keystone Jetty.

To me, it seems to be "how comfortable I am with the area". I feel like I know Skyline pretty well, and unless I see the kelp flapping like a flag, I am fairly comfortable getting in "when I get there"... lol I will also say that I am on a 130, so I hae air for days. I would certainly be a little more skittish to my approach if I was using an AL 80.

Gonna look for current software now!!!

Chad
User avatar
LCF
I've Got Gills
Posts: 5697
Joined: Tue May 30, 2006 5:05 pm

Re: Sat Mar 7th Deception Pass (almost)!

Post by LCF »

http://www.dairiki.org/tides/ has tide AND current information for a variety of sites.
"Sometimes, when your world is going sideways, the second best thing to everything working out right, is knowing you are loved..." ljjames
User avatar
Jan K
I've Got Gills
Posts: 5249
Joined: Fri Aug 04, 2006 5:02 pm

Re: Sat Mar 7th Deception Pass (almost)!

Post by Jan K »

I vouch for Pete ! He introduced me to shore dive at Deception Pass and if the gate was open I would be diving it ... Thank you Pete...
http://JanKocian.smugmug.com

I take photos because I like it, not because I'm good at it. :) by Unknown
Post Reply