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-   -   5 knot or more tidal flow (http://www.sailnet.com/forums/seamanship-navigation/72229-5-knot-more-tidal-flow.html)

southwindphoto 02-21-2011 06:16 AM

5 knot or more tidal flow
 
This past Saturday I elected to take my boat for a spin.
I moor my boat about 2 miles from the inlet and thus anytime we go anywhere we have tidal flow to contend with. .

Most days it’s 1-2 knots, so no big deal. This past Saturday it was more like 5 knots, we stopped at the City Marina for ice and the Harbour Master told us today’s 4 ˝ knots was bad, but he has seen it up to 7 knots.

What do you do when you enter an inland area with a tidal flow like this...? Does your sailboat have sufficient power to out power the flow so you can maintain bear minimum steerage, either into or with the tide?

Not only is downtown St Augustine that way, but so downtown Jacksonville and I’m sure there are many such area.

Sure I know the easy response it wait for the tide to slack, but for a working person, with limited time each week on the water, waiting six hours is a luxury, not readily available.

Our answer was to move the boat to salt run bay... Much slower flow, but we still have the main bay and inlet flow to contend with.

Tempest 02-21-2011 07:29 AM

If you can only motor @ 5 kn. You really have no other choice other than to wait.
I don't feel comfortable in an inlet bucking a 4 1/2 kn current. Tidal flows are dynamic, you don't nec. need to wait for slack, just avoid the peak flow. Bucking 1 or 2 kn isn't too bad.

paulk 02-21-2011 07:59 AM

Sometimes you can work your way against the flow by the edges, where it will be slower and there may be back eddies. If you have to wait, time and tide are part of sailing too. Otherwise, why not get a Bayliner?

Faster 02-21-2011 08:57 AM

The math simply says sometimes you have to wait. The tide and current tables are there so that you'll know when those times are and schedule yourself accordingly.

We lived behind a narrows that could run up to 9 knots at spring tides.. there was no 'bucking' that. In addition to the raw current you have to be cognizant of the sea conditions caused when a strong wind opposes a strong current - even if the current is aiding you it may not be wise to transit under certain conditions.

BC waters are full of such time-sensitive narrows... some of the extreme ones will look like this: (Flowing about 10-12 knots here)

http://i213.photobucket.com/albums/c...ruise08021.jpg

southwindphoto 02-21-2011 09:00 AM

Quote:

Originally Posted by paulk (Post 700449)
Otherwise, why not get a Bayliner?

Good one.. :cool:



Well in studding tidal charts this morning, I happen to pick the worst day possible for going for a spin on the sailboat...

Tidal changes were over 6 Feet that day and the almost full moon, amplifying the normal 4 1/5 foot change going out.

Add to that a countering 15 knot NE wind, made for a “fun” ride.

Yes we made it but only buy using a crisscross tacking pattern and full power from time to time.


The fun part was watching a 45-ft Hunter sailboat go through the same area like there was nothing to it.

Obviously had a lot more power than my little 28 HP diesel.

jackdale 02-21-2011 09:38 AM

Faster - great shot of Skookumchuck

I use the following guidelines for going through passes with a tidal current. The speeds are based on the maximum current on either side of the turn.

0 - 3 knots: anytime
3 - 6 knots: 30 minutes ether side of the turn
6 - 9 knots: 15 minutes and getting shorter

These are what I teach in coastal navigation. In reality we sometimes have to do otherwise. east of Campbell River, Yuculta Rapids, Gillard Pass and Dent Rapids have to be done one right after the other. We start through the Yucultas one hour prior to the turn to ebb and catch counter currents to carry us through. This way we get through Dent Rapids before a strong ebb develops.


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