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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.
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.