# Report of the Brann Tidal Survey for the season of 1987

Prepared at the Old Customs House, Port Ilvess, for the Council of the Institute, and respectfully
submitted.

The Brann Tidal Survey (BTS) completed its thirty-fifth consecutive season this year with all nine
stations reporting and no loss of record at any of them, a result the Survey does not take for
granted and the weather did its best to prevent. The season opened with the usual proving of the
gauges in April and closed with the equinoctial series in late September; what follows is a plain
account of the work, with the detailed sheets bound separately as always.

The nine stations stand as before: three about the harbour and roads of Port Ilvess, two on the
west coast of Ilvess at Corrie Ness and the Long Skerry, two on Sarn at Sarnholt and the Hot
Spring landing, one on Little Moriny at the light, and the outer station on the Fell Rocks, which
continues to be the most expensive item in the Survey's budget per foot of paper it produces. All
gauges were proved in April against the travelling standard, and the travelling standard, as
always, against the KSB before it left the building and again on its return. Pressures throughout
this report are reduced against the KSB series in the usual manner, and heights are given on the
Survey datum of 1953.

The tidal year was unremarkable in range and remarkable in temper. The spring series ran close to
prediction through the whole season, seldom off by more than a hand's breadth at any harbour
station; the equinoctial gales, by contrast, drove two storm surges through the roads in
September, the greater of which put the fish market arcades under water for four hours and the
Survey's opinion of its seawall predictions under review for rather longer. The surge sheets have
been copied to the harbour board with the Survey's compliments and its renewed recommendation
regarding the height of the north quay, which the board has now declined, with unfailing
courtesy, for eleven consecutive years.

The harbour tide clock deserves its annual paragraph, and this year rather more. Proved daily
against the transit series through the whole season, the clock has kept its rate within
four seconds in the month, a performance no instrument of its kind on the mainland approaches, and it
did so through a summer in which the tower it lives in was twice struck by gulls of unusual
conviction and once, during the September surge, by a fish. The clock is Ferrick's, as the whole
Republic knows, and the Survey's only standing complaint against it is that it makes the rest of
the season's instruments look idle.

The levelling party had a season of unusual interest. Extending the datum inland for the harbour
board's drainage scheme, the party carried the levels up the Sarnholt track and, the weather being
kind and the party being ambitious, closed its triangle on the summit of Mount Sarn. The Survey's
adjusted result places the summit at 2,315 metres above the Survey datum. The computation has
been checked twice and the field books are clean; the Survey is aware that the figure will raise
eyebrows in certain almanac offices, and confines itself to observing that the theodolite was
proved on the transit pillar before and after the season and that mountains do not read almanacs.

The Survey records with regret the retirement of Mrs H. Corliss after twenty-two seasons at the
Little Moriny station, whose sheets were the cleanest the Survey has ever received and whose tea
was the reason the proving party always began its rounds in the north. Her granddaughter takes up
the station book with the new season.

For the coming year the Survey proposes no change of station, one change of method — the Fell
Rocks gauge to be converted to the sealed recording pattern, if the Instrument Works can spare
one before the autumn — and its customary request to the Council for a second computer, by which
the Survey means, as it has meant every year since the request was first entered, a person who
computes.

Submitted this 30th day of October, 1987, at the Old Customs House.
