In article , Marc Heusser wrote:
In article ,
Justin C wrote:

Out of interest, how far is too far?

Ok, here comes the comparison.
(LW low water, HW high water, 24h time, height above map reference zero
for Hamburg, St. Pauli, Germany, 53°32'44"N 9°58'12"E, GMT+1
for Monday, 23 March 2009
(This is the large port of Hamburg)

The reference: prediction by th BSH
(www.bsh.de, free)
HW 0151 3.9m
LW 0927 0.4m
HW 1439 3.7m
LW 2147 0.5m

WXTide32 (latest version 4.7, 25 Feb 2007, wxtide32.com,
for 53°33.00'N 9°58.02'E, free)
HW 0133 3.1m
LW 0905 0.5m
HW 1428 3.0m
LW 2113 0.6m

That's out by a fair bit, on the high at least. To be working out calculations on almost 4 and find out it's really around a meter less, that could be a problem. But I'd always *try* to arrive before the bottom of a low... try being the operative word. Mind you, 3 meters wouldn't be much of a problem for most cruisers, as long as there isn't much of a swell.


Tides (iPhone, version 2.0, free, but ad ridden)
I was not able to enter Hamburg, Germany, a major port, with the new
version, even when I entered the exact coordinates and searched for
nearby prediction spots.

TideApp (iPhone, version 2.5, ads to come - I'd rather pay something for
it)
HW 0143 3.9m
LW 0901 0.75m
HW 1425 3.7
LW 2128 0.75m
Times seem to be within half an hour, heights within half a metre
good enough for planning

Mr Tides X (Mac OS X. version 2.5.6.2,
http://homepage.mac.com/augusth/MrTides/, based on XTide 2.8, free)
HW 0143 3.9m
LW 0901 0.75m
HW 1425 3.7
LW 2128 0.75m

I have XTides on my palm. I find it compares quite well with the local published tides, but I've not done a direct comparison over time. I think I shall.

It is said, I believe, on the XTides page, that the figures are calculated, and that, if you want better accuracy you should use published tide tables. While the published tables are calculations too, they're calculated for each port individually, while XTides is calculating based on less actual data - due to storage restrictions (at least on a palm).

Justin.

--
Justin C, by the sea.