The Pottership Race

by Ken Kershaw

The Pottership Race was presented by Major Cyril Potter in 1937 and awarded annually to the winner of a handicap race for all classes of keel boats owned and sailed by members.  It still runs to this day.

Notes following the 2020 race from the PRO

Ken Kershaw

Some historical comments from past Potter Bulletins

1951 – 19 starters

1959 – won by a Folkboat (not Nordic).

1961 – won by an XOD.

1962 – no wind at start, yachts kedged on line.

1963 – “The closing stages of the race were full of incident owing to the necessity to beat up the river against a northerly wind, shortly after low water, albeit a neap tide, this led to many grounding, some retirements one or two near misses and one actual bump with the ferry”. After which it was decided to finish at the Platform if the same condition reoccurred.

1964 – 50 starters with a spinnaker run to the finish at the Club.

1974 – Over 80 starters

1976 – 50 starters in a force 6. “As a result of severe congestion at the weather end of the line and a certain lack of understanding of one or two of the fundamental rules of racing by some competitors, alternative arrangements for starting the race in future years will now have to be considered.

1980 – “The Potter Ship race is always fun and with the quadrilateral course, fixed certainly since the war, conditions vary considerably from year to year”.

1982 – “For those who managed to get round Black Rock in reasonable time before the wind dropped it became a race – for those who did not it became either a backward passage race towards the Needles or kedging in seven fathoms or more”.
Potter Bulletins ended in 1986 in preference of the Potter Ship magazine in which there are few Potter Ship race reports.

The Course

Attached as Appendix B are some notes I wrote a few years ago giving acronyms (well two out of three) to some course setting concepts – STAD, EaRWiG and DAD. I’d like to introduce one more – SCIF standing for Start, Course, Interval and Finish. These are, by stint of the RRS, the main areas of responsibility allocated to a RO – the start, the course, the interval (duration) and the finish – SCIF.

The Start

Historically the start line has been from the Platform with the only change being made after a problem in the 1976 race since when the fixed outer end Mark D has been replaced by a movable ODM. However, there are other problems with the historic Platform starting line the primary ones being: –

a)     The difficulty in setting a start direction in the arcs from about 220° through north to about to 70° and about 150° through southeast to about 180°.
b)     The closeness of the line to the River entrance and possible interference with other users.
c)     The depth on the line at certain tides.
d)     The depth of water to the west of the River.

Problem a) is not that major as a reaching or running start has been generally thought to be acceptable for the race.

Problem b) is of concern and has on more than one occasion impinged on the race. Our current starting time is 10:10. The ferry time table includes a 10:00 sailing and it takes an outgoing ferry about 12 minutes from Lymington Pier to be abreast the Platform. If only two ferries are in use the incoming ferry is likely to pass the Platform some 5 minutes after the outgoing ferry. Given that ferry timings are variable (in 2020 the outgoing ferry was late and there was no inbound ferry) a 10:10 westbound start can be delayed by ferries for anything up to 15 minutes.

Problem c) The inner end of the Platform line has a charted depth of about 2 metres above datum.  EAGER, a 2020 entry, has an IRC certificated draft of 2.62 metres.

Problem d) When the wind is in the north or south and particularly when light the difficulty in setting a windward leg on the north shore to the west of the river tends to compel an east going start which may not be tidally desirable. This was the case with the 2020 race. Move the start just some ¾ mile to the east of the River and this problem would go away.

An alternative to a Platform start could be a Committee Boat start. Such would make it possible to avoid much of all the above Platform start problems and also lead to more course options e.g. a southerly first mark.  It would also remove the need for Race Team transfers to and from the Platform which would improve safety. A downside to a Committee Boat start would be the sourcing of a suitable boat, a power cruiser of 40 ft. length or more.
Building a new platform off the entrance to Pylewell Lake would solve most of the problems.
Changing the start time would solve problem b).

The Course

Conventionally most races start and finish with a beat and hence require a windward and leeward mark. This is the simplest of courses – a sausage. But a sausage course (particularly on an east west running tidal shore) can advantages some yacht designs over others e.g. symmetric vis asymmetric spinnakers. A third mark offset from the first mark can be used to force a reach and square up a run and equalise some of the design differences. So the simplest course for the race in our waters would tend to be a triangle.

The Potter Ship race has always been based on laps. Historically this was two laps often shortened to one but with the ALR, as its name suggests, there has to be laps and the more the better. In both of these cases the lap starts and finishes at the same line/gate i.e. the start and finish of each lap.

With our fixed marks the shortest length triangle that can be set from the Platform is likely to include E, F and C marks (0.65, 0.45, 1.15 and 0.6 = 2.85 NM). Using STAD (Appendix B) and the table in the RRS (page 200) the time for slow and fast(ish) boats in different winds speeds to complete this lap would be: –

5 metre boat 9 metre boat
Wind speed (kn) Speed (kn) Lap time (h) Speed (kn) Lap time (h)
5 1.1 2.6 2.0 1.4
11 2.6 1.1 4.5 0.6
22 5.1 0.6 9.0 0.3


Interestingly in the 2020 race with much the same triangle course the elapsed average lap time for the slowest boat was 1 h 49 mins (1.8 hours) and for the fastest 54 mins (0.9 hours).

Further observations on courses are to :-

  • Avoid shallow marks (DAD)
  • Try to apply EaR-Wig which can be difficult in low winds as there is not opportunity to set a short north/south leg to the west of the Platform owing to depth constraints.
  • The SIs need to prohibit boats from passing through the Gate the wrong way.

The Interval or Duration
The above tends to suggest that for all competitors to finish the race in a 5 kn wind with the current target time of 2 to 2½ hours (the interval) the course lap length for an AALR needs to be about the 2.8 NM or not much more (up to 3.3 NM).

have finished in 1 hour 58 minutes and the last boat would have timed out. With the ALR this year all boats finished, the first boat in 1 hour 58 minutes and the last in 1 hour 59 minutes.

An alternative to “short” lap lengths could be to increase the target time (interval). Not only would this improve course opportunities in low winds it could be used to increase the number of laps and hence, with ALR, lower the finishing time span in higher winds. Okay bar opening hours might need to be changed to retain the same profitability together with having a later luncheon or we could just agree to race some more like we used to with this race.

The Finish
Since the 1960s when a competitor “bumped” the ferry whilst finishing at the club the finish has been at the Platform. Whatever the case, Handicap or ALR, Platform or Committee Boat, start the finishing line needs to be at the same point in the lap as the starting line.

The Race

Commonalities between historic and today’s race

Held on the first Saturday in October no matter what the tide

Platform start
Rounds (historically 1 or 2, today ALR)
Open to all club boats with a keel no matter what speed

Things that have change over the years

The starting line was fixed with the ODM being D mark. Now a movable ODM.
The finishing line was the river club line. Now a movable Platform line.
The course was a fix quadrilateral as B, 1, 4, H, D all to port or the other way round. Now set on the day and may include movable marks.
The time limit or target time today is 2 to 2 ½ hours whereas it was 14:00 on the day of the race.
The race is now an Average Lap Race rather than a simple Handicap race.

Type of Race

Handicap vis Average Lap Racing (ALR)

Average Lap Racing (ALR) has only been promoted by the RYA since the turn of the century and only used for the Potter Ship race for the last few years.  A copy of the RYA 2007 details are attached as Appendix A.

The main difference between Handicap and ALR is that with Handicap racing the faster boats finish first with the slower following on racing over the same distance as the faster boats but in different wind/tide condition. If the wind progressively increases during the race the slower boats are advantaged whereas if the wind progressively decreases (or shuts off) the slower boats are disadvantaged. Tide can accentuate these effects either ways.

With ALR, provided at least some boats complete more than one lap the fleet will finish over a shorter time span and hence have raced in more of the same wind and tide conditions. With a typical Potter Ship fleet and course the finishing time span decreases proportionately to the number of laps completed by the first boat – 1 lap (which is the same as a simple Handicap race) and the finishing span is the time for that 1 lap, 2 laps and the finishing span can be as little as ½ the lap time, 3 laps and it can be ⅓, 4 laps gives ¼ and so on. So the more laps the more consistent the wind and tide for all boats. This suggest that no matter what the conditions an ALR with at least some boats completing 2 or more laps is “fairer” than a simple Handicap race.

A common hypothesis for both types of race is that the race will benefit certain speeds of boat depending on the time of day and with ALR, where in the fleet the About to Finish (ATF) is signalled.

With a morning race the wind tends to increase during the race. This will benefit slower boats in a Handicap race. In an ALR, boats that have just crossed the line prior to the ATF signal will be benefited as their last lap (sailed whilst other boats are finishing) and hence their average lap time will be faster.

With an evening race where the wind dies off the faster boats will benefit in a Handicap race and, in the ALR, the first to cross the line after the ATF signal.

This hypothesis, whether or not true, is perceived and so with an ALR it becomes important to determine when to signal ATF. Ideally and contrary to the RYA recommendation this should be undertaken just prior to mid fleet TCF boat crossing the line. This will optimise any changes in conditions. But care should be taken to avoid “splitting” a class of boats as this is likely to produce a step in their average lap times and even change boat finishing positions within the class. Making the signal should also take note of the target race time and whether or not there are any time limits (see RYA paper).

Summary and suggestions

a)     Average Lap Racing is more “fair” than Handicap racing as it reduces the time span over which boats finish.
→  ALR should be continued.

b)     The current Platform starting line has some inherent problem.
→  The starting line (and hence finishing line) should be changed to a Committee Boat.

c)     ALR, as suggested by its name, requires laps and the more the better. The current race target time restricts the number and/or length of the laps.
→  The target time should be increased.

KK – 13 Oct 20

Appendix A


Appendix B

Some notes on West Solent course setting by Ken K
Words to remember: –

Speed, Time and Distance
To determine the race Distance, you need to know the Speed of the boats and the Time for the race.
Boat speed can be estimated from the boat velocity table data on pages 200 of the RYA RRS booklet. These speeds will need to be adjusted for planning boats.
The race time can usually be estimated by the time limit given in the SIs. Consider the likely difference between the lead boats and the back markers. With handicap fleets the range of time limit is likely to be greater than with one-design classes.
Once you have a speed and time then you can calculate the distance.
A knot is a mile an hour so if the time is 1 hour and the speed is 3 knots then the distance is 3 miles. This can be plotted on a chart steam fashion or by a pre marked string or by adding up the distances given between marks as given on some chartlets.
East moving tide give Red (port) rounding courses
West moving tide give Green (starboard) rounding courses
These rules hold true for the north side of the West Solent.
If you set the mark roundings the other way then boats can be stuffed by the tide or, when leaving a mark, boats are likely to cross back over the track of boats coming to the mark. This can be dangerous.
Distance, Angle and Depth
This is as much a consideration for mark layers as for the course setter and so first a word about movable marks.
Having over the years raced big and small boats in the Solent, acted as a course setter, a PRO and a been a mark layer it is my opinion that the use of movable marks should be kept to a minimum!
With big boats there are numerous fixed marks available all set in good water in known positions.
On many occasion I have seen a movable mark
·       set less than a 100m from a fixed mark
·       set in the wrong position
·       set in too shallow water so boats can’t get around it
·       set in too deep water so it drags
·       the whereabouts not correctly conveyed to the sailors
·       and so it goes on
and my arms are now too long and my back too sore from laying and recovering these.
Use fixed marks as much as you can.
Okay this is not always possible particularly with small boats and here is the importance of DAD. With movable marks you need to determine the position of these and this is best done by use of a distance and angle – D&A, from a known position. The LTSC used D&A from Jack in the Basket. Most of our dinghy events use D&A from the committee boat and or from a previous mark. At some events with large courses with marks over the horizon I have used D&A from a fixed chart point often the centre of a compass rose.  The mark positions are easily laid off using chart work and or GPS.
The final D in DAD is depth which is self-explanatory provided you remember this D is always changing. E.G. our river mark Seymour’s has no depth at certain times!