Day Island Wall Friday 9/13

[Anderthal]

Hi Everyone. My buddy and I are planning to dive Day Island Wall on Friday 9/13/13. We've both dived there before with regulars, but this time we're going on our own and I was hoping someone more knowledgeable with the site could review my slack prediction and provide advice on our dive plan.

I have calculated that slack before ebb will occur at about 1:25pm. We are planning to be in the water at about 1pm and be pushed south a ways, then back north to the entry point once the ebb starts. Does this dive plan make sense? Any advice?

Thanks!!
Andy

[Jeremy]

I'd do that dive imo

[Jeff Pack]

Your timing is abit off though, most folks use 45-1hr prior to slack. I'd be looking more at a 12:15-12:30 splash.

[fmerkel]

N. Narrows 9/13: 3.7 > 1:30 slack > 1.5.
3.7 is hefty. 1.5 is puny. Lean away from the heavy toward the weak.
Jeff is closer to the mark, if you plan to try to ride the switch back. I time it so the slack happens more when I'm down toward South Bay. There's a down and out current down that way that's worth avoiding. You can do that by returning on the wall and not going up slope. I like to have the option.

Last couple times I've been in on the tail end of a flood for a trip south I was late for the current though I splashed right on time. I'd be interesting in knowing your splash, current direction, and switch time if it happens.

[GearHead]

I agree you want to be hitting the water 45 min - 1 hr before slack. It takes a while to swim out to the wall, and you don't want to be caught in the ebb current as you're coming back over the wall.

[mpenders]

You also need to consider how much air you're carrying, and what your consumption is. The wall to the south gets deep - and the further south you go, the deeper the top of the wall gets (and it heads further away from shore).

I find that the slack before ebb changes earlier than slack before flood. Personally, I'd want to be in the water no later than 12:15pm (with the expectation that I would be underwater for an hour). If your average dive time is less, then get in the water later.

[Anderthal]

Thanks so much for the replies and insight. It all makes sense (except for Jeremy's "imo". I'm not quite sure what that means).

Another question, Can you tell me why the Narrows North current station is used when there is a current station closer at Narrows South?

Also, the inshore back eddy that happens on the flood. Is that inshore from the wall always, or can it extend out to and over the wall?

Thanks again we'll plan to splash at 12:15 and I'll post results.

Ps- were diving with steel 119s.

[Waynne Fowler]

Jeremy was giving you his opinion... IMO = "In My Opinion"

[mpenders]

Another question, Can you tell me why the Narrows North current station is used when there is a current station closer at Narrows South?

Because that's what I'm accustomed to using

My go-to tide/current resource is usually http://www.dairiki.org/tides/daily.php/nar. It only provides a Narrows North station, so that's what I use - then apply corrections as necessary for the specific site I'm diving.

[fmerkel]

There are only 7 current stations in the Sound. Everything else is interpreted. It's not interpreted for divers, so you need to take that into account. The S. Narrows is 'generally' within 5-15 minutes of north. Sometimes it's more, don't know why.
S. usually shows larger exchanges. In reality it doesn't matter which one you use as long as you keep using the same 'ruler' to measure your correction with. I also use S. Narrows but look at N also.

The so called reverse eddy is there. IMO it's not reliable, and should not be depended on for the dive. It's more of a diver DIW fable than a sure bet. Frankly I ignore it unless I actually find myself in it.
I have seen what is an obvious outward bound collision rip of probably 2 knots several times right in front of the N. entrance that was completely gone 10" later. This rip can migrate somewhat N. or S. Again, I don't know why it's there sometimes, but not others.
I've been right on the wall with current ebbing below the wall, while 10 feet away above the wall it was flooding. 5" latter it was kicking my ass. Sucked down 1500psi in 5" getting to the shallows. These are rare events on a properly timed dive, but it's DIW and that's why it's an advanced current dive.

In 15 years of diving there I have never been in a down current on the wall. I HAVE been in the outbound current, which will take you deeper, or grind you to a halt if you are fighting it, when trying to come up slope from S. Bay (70 feet). That is a humbling and frightening experience.

[Anderthal]

Well, we had a fantastic dive at Day Island yesterday! We ended up chatting with the guy at Tacoma Scuba shop and he said that he uses the Narrows South table when he dives there. We splashed at 12:45 and encountered a very mild current flowing north -- it pushed us a little north of the entry but not significantly. I assumed the ebb was starting but when we dropped down, there was almost no discernible current. We were down for an hour and the conditions persisted the whole time. We didn't range too far north or south once on the wall -- and there was no need since there was so much to see. Lots of octos (saw 4 within the first 10 minutes) and a very friendly wolf eel. Overall, almost no water movement, good viz at about 20-25 ft., excellent topography, excellent life. A very pleasant dive for my buddy's 45th birthday.

Thanks to everyone for the conversation. Its great to learn so much about this site.