Havengore Bridge

[Cantata]

Hmm. OK. I have found Navionics to be very accurate with depth but I don't have your wide experience.

Navionics do not do any surveys! Any data they use comes from the UKHO, supplemented by anything that users care to submit as modifications, even then unverified as I understand it.
As Tillergirl says, there would not have been any official survey of an area like this for many many years, nor is one likely ever to be be done.
I have been shown many anomalies on local Navionics charts, 'features' which I know simply do not exist. For that reason I will not have Navionics in my chartplotter.

 

[stu9000]

I might have gone for this in my old twin keel jag 27 but i think there is too much risk in the single keel heavier Seahawk. From what's been said there may be just enough water, but only just and there just isn't enough of a safety margin. I don't want to pound on that sand. Thanks very much for all the info.