Deben Bar 2013

[PeterR]

With no East Coast Rivers chartlet to help any more I thought forumites who were yet to launch might find a few notes and this video of use when they come to cross the Deben Bar for the first time this year.

We launched on the 10th of April when HW Harwich was 12.47 – 4.01m. We winter at Larkmans yard (above Woodbridge and just below Melton Bridge). Steve always seems to put us in about 15 to 20 minutes before local HW and we inevitably end up crossing the bar just about exactly 2 hours after HW on the bar.

Approaching Mid Knoll from upstream it seemed to be a little closer to the Ferry shore but not dramatically different from last year. However, West Knoll has been moved a long way and to locate it you just keep on the same track you are on coming down the river. It seemed much further off than previously and being well to the south it was difficult to distinguish its colour and shape against the sunlight. I had to get the glasses out to confirm that we were not heading for a fishing boat.

Once past Mid Knoll we found that keeping Mid Knoll in transit with the gable end of the Felixstowe Ferry Sailing club kept us on track. In the sunlight the gable end was very conspicuous. The least depth we noticed was 3.0 metres and that was about half way between West and Mid Knoll. Last year we launched on 6 April on a 4.1 metre tide and found a least depth of 3.3 metres and that was just a couple of boat lengths from West Knoll. So the depth appears to have reduced slightly but not enough to pose a problem.

The original video is high definition and the distant buoys are easy to see but on You Tube the definition is degraded and you may have difficulty picking out West Knoll from a distance. To have any chance click on the YouTube icon and view in full screen

 

[Capt Popeye]

Ahoy there - thank you for video; much enjoyed it!

For personal choice /preferences I would much consider stopping over at either The Rocks or Ramsholt and going over the entrance bar, either on the last of the flood or just before the top of tide.

And so enjoying the Deben a little longer.

Anyways, great video much enjoyed, as I said above.

 

[Oldgeezer]

Many thanks

I'm launching beginning of May, and was getting nervous without the guidance of the chartlet.

I can usually get to the deben bar an hour before HW.

so it looks good +- 2hrs even for neaps. (1 meter draft).

Again. many thanks.

 

[Otter]

Nice video, you were following us on our way to the Rocks, we are that nice looking ketch ahead of you at Loaders Cut

 

[forelle541]

is that not Loders Cut?

 

[Athene V30]

We launched on the 10th of April when HW Harwich was 12.47 – 4.01m. We winter at Larkmans yard (above Woodbridge and just below Melton Bridge). Steve always seems to put us in about 15 to 20 minutes before local HW and we inevitably end up crossing the bar just about exactly 2 hours after HW on the bar.

Last year we launched on 6 April on a 4.1 metre tide and found a least depth of 3.3 metres and that was just a couple of boat lengths from West Knoll. So the depth appears to have reduced slightly but not enough to pose a problem.

Interesting - thank you.

2013 at HW+2 on 4.01m tide - least depth 3.0m
2012 at HW+2 on 4.1m tide - least depth 3.3m
Indicating about 20cm shallower this year.
What was atmospheric pressure - do you happen to have a record to compare year on year? It has been high recently so that has the effect of reducing the height by 1cm per 1mb. If 2012 launch was at low pressure there may be very little shoaling over the 12months.

 

[davidfox]

How have you calibrated your depth sounder, depth under the keel or water depth and did you say what you draw?

Good video by the way

 

[PeterR]

Interesting - thank you.

2013 at HW+2 on 4.01m tide - least depth 3.0m
2012 at HW+2 on 4.1m tide - least depth 3.3m
Indicating about 20cm shallower this year.
What was atmospheric pressure - do you happen to have a record to compare year on year? It has been high recently so that has the effect of reducing the height by 1cm per 1mb. If 2012 launch was at low pressure there may be very little shoaling over the 12months.

I was not offering the data as any form of survey, merely an observation of the depths we found on the tracks we happened to take on two separate occasions.

As you say to make a meaningful comparison the tidal data needs to be standardised. Knowing the barometric pressure is not enough as it is only one of the factors that can affect actual tidal height. Despite recent high pressure, according to the DOBC database the actual tidal height at HW Harwich on the 10th April was 4.096 against a prediction of 4.01. However, getting data beyond three months is more difficult than it used to be and I gave up waiting for a download for 2012.

Although my echo sounder is calibrated against a lead line that is in my berth which may well not be flat and I would not be surprised if it under reads by 0.1 judging from observed readings when we have touched the putty. Additionally the precision of the sounder is only to 0.1m without rounding so a reading of 3.0 could in fact be anything from 3.00 to 3.09.

All that it is reasonable to read into the figures is that there appears to be slightly less water than last year but not enough to make any significant difference.

That supports the view of the harbour master, John White, who I am told at a recent talk advised that he felt the depth on the bar had reduced a little but that in moderate conditions it was still safe for a vessel drawing 6 feet to enter/leave from HW-3 to HW+2.