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TakeFive 01-27-2013 01:01 PM

Currents in the C&D Canal
 
Refer to these messages here, then please post responses in this thread.

jameswilson29 01-27-2013 01:34 PM

Re: Currents in the C&D Canal
 
I am all in favor of currents when they help me get where I want to go; I am strongly opposed to currents which prevent me from going where I want to go.

The C&D canal is a surprisingly lovely area. It would be even better without the currents.

RichH 01-27-2013 01:58 PM

Re: Currents in the C&D Canal
 
Several factors control the current in the C&D canal

1. Tide amplitude on the Del River is 6ft., 1.5ft. on the Ches. Bay.
2. The Del River is a 'flowing river'.... adding to the tide height by virtue of its volumetric flow direction.
3. The Filling and draining of inlets, narrow rivers and canals usually 'lags' the high/low tide times, due to hydraulic geometries such as 'choke points', bottom contours, etc. etc. etc.

... all this means your really cant look at tide data and outguess what Historically is the actual flow direction in the C&D.
This historical data of 'actual' current flow, direction and strength is found in historically compiled data based on ACTUAL observation .... such as Eldridge Tide Tables ... and some 'programs' (probably based on Eldridge).

Rule of thumb for traveling the C&D going east, and to 'ride' the 'crest' of the outgoing tide all the way down to Cape May:
Gong 'east then down' - Leave the Engineers Cove at Chesapeake City 2 hours BEFORE low tide at Chesapeake City ... maintain 6kts. and ride 'the wave' all the way down the Del. Bay

Going north on the Del Bay, 'north then west': leave Cape May Point AT low tide or shortly before dead low, maintain 6 kts. and ride the tide wave all the way up the Del. Bay and through the C&D, expect the tide to turn AT Chesapeake City and ride the ebb down the Chesapeake to at least Baltimore/Annapolis.

Note: if there has been heavy rainfall in the Delaware Valley ... all bets are off as to 'timing' due to faster and increased water flow coming 'down'. Ditto with Heavy rainfall in the Susquehanna Valley and the Susque is 'backfilling' the C&D. Ditto but opposite effect with extreme drought in those river valleys.

Other: dont travel on the Del. Bay if there is strong NW or SE winds predicted or blowing, especially if youre 'against' the tide. 6-8ft. very steep chop is 'traditional' w/ strong NW/SW 'blows' on the shallow Del. Bay.
Other2: Only two places to anchor in 'protected water' on the whole Del. Bay between C&D and Cape May: 1. Cohansey River - with BIG tide/current flow, 2. Maurice River (way off the 'beaten path')
Other3: With 'light' winds, Expect to be 'eaten alive' by 'greenheads', stable flies, various gnats, and mosquitos during 'wet' or 'spring' - the reason nobody lives along the shores of the Del. Bay.

Ulladh 01-27-2013 03:50 PM

Re: Currents in the C&D Canal
 
There may only be a few optimal or even best times to transit the C&D either way or with respect to ebb or flood in the Delaware, point of beginning and final destination.

Even if one selects the absolute wrong time, the maximum current in opposition will be for less than 1/4 of the transit.

On the evening of June 7th the maximum current in opposition will be about 1.5 knots, an extra pint of fuel and about 2hrs extra for my transit.

chef2sail 01-27-2013 04:26 PM

Re: Currents in the C&D Canal
 
Quote:

Originally Posted by RichH (Post 981845)
Several factors control the current in the C&D canal

1. Tide amplitude on the Del River is 6ft., 1.5ft. on the Ches. Bay.
2. The Del River is a 'flowing river'.... adding to the tide height by virtue of its volumetric flow direction.
3. The Filling and draining of inlets, narrow rivers and canals usually 'lags' the high/low tide times, due to hydraulic geometries such as 'choke points', bottom contours, etc. etc. etc.

... all this means your really cant look at tide data and outguess what Historically is the actual flow direction in the C&D.
This historical data of 'actual' current flow, direction and strength is found in historically compiled data based on ACTUAL observation .... such as Eldridge Tide Tables ... and some 'programs' (probably based on Eldridge).

Rule of thumb for traveling the C&D going east, and to 'ride' the 'crest' of the outgoing tide all the way down to Cape May:
Gong 'east then down' - Leave the Engineers Cove at Chesapeake City 2 hours BEFORE low tide at Chesapeake City ... maintain 6kts. and ride 'the wave' all the way down the Del. Bay

Going north on the Del Bay, 'north then west': leave Cape May Point AT low tide or shortly before dead low, maintain 6 kts. and ride the tide wave all the way up the Del. Bay and through the C&D, expect the tide to turn AT Chesapeake City and ride the ebb down the Chesapeake to at least Baltimore/Annapolis.

Note: if there has been heavy rainfall in the Delaware Valley ... all bets are off as to 'timing' due to faster and increased water flow coming 'down'. Ditto with Heavy rainfall in the Susquehanna Valley and the Susque is 'backfilling' the C&D. Ditto but opposite effect with extreme drought in those river valleys.

Other: dont travel on the Del. Bay if there is strong NW or SE winds predicted or blowing, especially if youre 'against' the tide. 6-8ft. very steep chop is 'traditional' w/ strong NW/SW 'blows' on the shallow Del. Bay.
Other2: Only two places to anchor in 'protected water' on the whole Del. Bay between C&D and Cape May: 1. Cohansey River - with BIG tide/current flow, 2. Maurice River (way off the 'beaten path')
Other3: With 'light' winds, Expect to be 'eaten alive' by 'greenheads', stable flies, various gnats, and mosquitos during 'wet' or 'spring' - the reason nobody lives along the shores of the Del. Bay.

Rich,

We have success anchoring behind Reedy Island in staying out of the blows as well as chop also

Dave

RichH 01-27-2013 04:56 PM

Re: Currents in the C&D Canal
 
Quote:

Originally Posted by RichH (Post 981845)
Several factors control the current in the C&D canal

1. Tide amplitude on the Del River is 6ft., 1.5ft. on the Ches. Bay.
2. The Del River is a 'flowing river'.... adding to the tide height by virtue of its volumetric flow direction.
3. The Filling and draining of inlets, narrow rivers and canals usually 'lags' the high/low tide times, due to hydraulic geometries such as 'choke points', bottom contours, etc. etc. etc.

... all this means your really cant look at tide data and outguess what Historically is the actual flow direction in the C&D.
This historical data of 'actual' current flow, direction and strength is found in historically compiled data based on ACTUAL observation .... such as Eldridge Tide Tables ... and some 'programs' (probably based on Eldridge).

Rule of thumb for traveling the C&D going east, and to 'ride' the 'crest' of the outgoing tide all the way down to Cape May:
Gong 'east then down' - Leave the Engineers Cove at Chesapeake City 2 hours BEFORE low tide at Chesapeake City ... maintain 6kts. and ride 'the wave' all the way down the Del. Bay

Going north on the Del Bay, 'north then west': leave Cape May Point AT low tide or shortly before dead low, maintain 6 kts. and ride the tide wave all the way up the Del. Bay and through the C&D, expect the tide to turn AT Chesapeake City and ride the ebb down the Chesapeake to at least Baltimore/Annapolis.

Note: if there has been heavy rainfall in the Delaware Valley ... all bets are off as to 'timing' due to faster and increased water flow coming 'down'. Ditto with Heavy rainfall in the Susquehanna Valley and the Susque is 'backfilling' the C&D. Ditto but opposite effect with extreme drought in those river valleys.

Other: dont travel on the Del. Bay if there is strong NW or SE winds predicted or blowing, especially if youre 'against' the tide. 6-8ft. very steep chop is 'traditional' w/ strong NW/SW 'blows' on the shallow Del. Bay.
Other2: Only two places to anchor in 'protected water' on the whole Del. Bay between C&D and Cape May: 1. Cohansey River - with BIG tide/current flow, 2. Maurice River (way off the 'beaten path')
Other3: With 'light' winds, Expect to be 'eaten alive' by 'greenheads', stable flies, various gnats, and mosquitos during 'wet' or 'spring' - the reason nobody lives along the shores of the Del. Bay.

Quote:

Originally Posted by Ulladh (Post 981897)
There may only be a few optimal or even best times to transit the C&D either way or with respect to ebb or flood in the Delaware, point of beginning and final destination.

Even if one selects the absolute wrong time, the maximum current in opposition will be for less than 1/4 of the transit.

On the evening of June 7th the maximum current in opposition will be about 1.5 knots, an extra pint of fuel and about 2hrs extra for my transit.

The max. eastward setting current following a max high at during the max. lunar cycle at Chesapeake City is ~2.5kts. Check out the expected current for 1/29/13 as an example. This can occur with the Delaware River 'filling', and is for 'normal' water/tide levels. Ive seen 3+kts. several times in the C&D ... all depends on how high and how low the tides are for the day.

TakeFive 01-27-2013 05:07 PM

Re: Currents in the C&D Canal
 
Quote:

Originally Posted by chef2sail (Post 981913)
You guys may be ovethinking all this. You are certainly making my head swim...

Certainly not the first time I've been guilty of that! ;)
Quote:

Originally Posted by chef2sail (Post 981913)
Rick I thought you had Navionics or any other program since you have your computer at the helm. It tell you tide and currents and vector arrows direction at specific spots along the way or even at your location...

Yes, I use OpenCPN both at home and at the helm. It's a fantastic tool, and predicts both tide levels and currents at all the NOAA sensors just by right-clicking on the chart. However, it defaults to showing a graph for the present day. In order to bring up the tidal current graph for a day 4 months in the future, I need to click the "Next" button ~120 times. And I need to redo that every time I bring up a different graph. (Maybe a different commercial package would do this better, but OpenCPN works perfectly for almost everything else that I do.) So the old fashioned current tables, whether Eldridge or NOAA, are the best thing I have right now for future planning.

As I already mentioned, this whole thing is a learning process for me, but one that is worth it because I expect to be making a lot more transits through the canal going forward, and the lunar calendar is rather predictable so I can leverage what I learn for many future trips.

Quote:

Originally Posted by chef2sail (Post 981913)
...I know how to figure out with Eldridge and all, but in todays world where I know you are comptuer savy there is an easier more efficient less time consuming way.

Any route on the Delaware that lasts less than 5 hours is pretty simple to predict - just time it to stay in the favorable current. But when you go out for more then 5 hours (downriver) or 7 hours (upriver), planning becomes more difficult because you'll encounter a tidal swing during your trip. And turning into the canal makes it even more complicated because its ebb and flood are on a different timetable than Chesapeake or Delaware. That's why you (Dave) have to stop at Reedy Point every time on your way to the ocean, and why I suggested stopping off heading from Philly to Chesapeake. As you've noted before, going the opposite direction (ocean to Baltimore or Chesapeake to Philly) can be timed to proceed without a delay at the eastern end of the canal because the currents at the canal entrance are in sync with the river currents in that direction.

That complication is the reason I cobbled together a spreadsheet planning tool for the Philly-Chesapeake. I haven't seen another tool that does this.

jameswilson29 01-27-2013 05:22 PM

Re: Currents in the C&D Canal
 
My best run up the Delaware was timed to start one hour before flood at the end of the Cape May canal. Sure enough, I rode the current all the way up, through the canal, and down the Northern Chesapeake Bay. It was a wonderful experience...

Ulladh 01-27-2013 05:22 PM

Re: Currents in the C&D Canal
 
Rich
The max current on June 12th is 2.5, but on the evening of June 7 it is 1.5

On the Delaware River our maximum flooding from up state NY is usualy in the spring and at Essington may add another 2 ft to high tide, enough to still impact the flow at the C&D. Sandy produced an extra 3ft, at Essington but did not top the seawall 3ft above high high at Delaware City, it would have been a lot worse if Sandy had tracked over the Delaware Bay or if the watershed above Trenton had a rain event.

I have been in 3 knot opposing current approach the Chesapeake City Bridge from the Chesapeake which droped my speed from 4 to1 for about 30 mins, not something I would like to repeat but it was for a finite time.

TakeFive 01-27-2013 05:35 PM

Re: Currents in the C&D Canal
 
Quote:

Originally Posted by jameswilson29 (Post 981836)
I am all in favor of currents when they help me get where I want to go; I am strongly opposed to currents which prevent me from going where I want to go...

Well the feeling's mutual - the currents oppose you almost as much as you oppose them! :laugher (Only "almost as much" because your motor power allows you to make some headway against them.)

It all depends on your frame of reference, which in the technical sense could be Eulerian or Lagrangian. (Now THAT will make your head spin! :p ) FYI, my PhD is in fluid mechanics, and I do still use some of this stuff in my day gig.


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