Sunday HoRR?

February 9, 2015By

SO WHY IS THIS YEAR’S HEAD ON A SUNDAY ?

The one word answer is “Tides” – as any Tideway oarsman knows, although the Tide Tables do not dictate the time of outings, they do set out and limit the amount of time spent going in whatever direction.

When planning a major Race, it is clearly essential to factor-in the amount of time required for each part of the process – for example, an hour for a crew to get from Putney to a marshalling slot near Kew Bridge, almost two hours between first-start-to-last-finish and up to 90 minutes for the last finisher to make it back to (for example) the UL boathouse. There has to be sufficient water for all finished crews to be able to navigate safely around Putney Pier, and then along the Hard 2 or 3 abreast, not forgetting – for some returners – the shallows around Hammersmith Bridge and under Barnes Bridge. Further, do not forget daylight – even if their boat is equipped with lights, it is not completely safe to have a non-Tideway crew returning to its base in the dark.

From the competitors’ point of view, bear in mind the logistics of loading the club trailer, driving to London and relying on enough of the crew to have arrived early enough to off-load and assemble the boat (this before the row up to the Start area).

Chew over these constraints, and apply them to 400 crews (3,600 people). The result is that the start time for HORR in late March cannot be any earlier than 10.00 (and even that can be awkward and/or unpopular). The latest start time is probably about 15.00-15.30, but also depends on BST (see under).

All these considerations apply equally to our sister Races, modified by things like number of entries, length and orientation of the course, boat manoeuvrability, crew experience and skill level, and lighting-up time. These are the “known knowns” – we all have to also leave some elbow-room for “known unknowns” which come along on the day itself, such as weather conditions, the amount of landwater and/or work on a bridge.

To take this year’s Head, the Tide Tables for circa late March give:-

 

Day ~ Date Time HWLB Time HWPB Time HWPB + BST
Sat 21 March 1439 1510
Sun 22 March 1522 1553
Sat 28 March 0725 0754
Sun 29 March 0838 0909 1009
Sat 4 April 1408 1439 1539

Note:

High Water at Putney Bridge is 31 minutes after High Water at London Bridge

Only times that would give a Start in daylight are listed.

BST comes into force very early on 29 March.

Data from the PLA website: http://www.pla.co.uk/Safety/Tide-Tables

Our initial calculation was that Start time would be 1 hour after HWPB. On this basis, the times for 21 and 22 March were too late, as was 4 April – besides, that is over Easter weekend which we avoid. The implied Start on 28 March would be about 0900, which is far too early. However, the addition of BST to the listed time for 29 March would give a Start close to 1100, which is much easier for everyone to work with.

Fortunately, our good friends at the Vesta Veterans’ HOR have rather more flexibility than we do, and they very kindly agreed to swap dates. This was all agreed over a year ago, which is comparatively short notice for us – we have already arranged our dates for 2016 and 2017.

What then happened was our forced abandonment in 2014. One problem which we noted at one of the review meetings was the effect of wind-against-tide, which had been the prime cause of difficulty but which had only developed after crews had boated and the majority had assembled at the Start. We concluded that it would therefore be safer if we changed our Start time to be between 1½ – 2 hours after HWPB, by which time we would have a very good idea of how conditions would be during the whole Race.

Looking back at the time calculations, this would theoretically have allowed us to switch back to Saturday, but with a Start time of 0930-1000, which we felt would still not be viable – especially given the various preparations already in hand. We settled on 12 noon.

Readers will be pleased to know that the tides are very favourable for Saturdays in late March in 2016 and 2017.

Andrew Ruddle
Hon. Secretary, HORR

Filed in: Uncategorized