Seamark Placed for Margate Treatment Project

Main contractors are a consortium of

Black

Veatch

and

Costain,

with

Cornwall based

Seacore Ltd responsible for the marine side of the project. A new 1.8m diameter storm water discharge pipeline has been tunnelled beneath the seabed, emerging 600m offshore into a pre-dug 13m by 8m by 7m deep pit then upwards to a diffuser

with

two Tideflex Duckbill valves centred approximately 1.8m above the seabed. The pit was then filled

with

a grouted granular fill topped

with

two concrete mattresses wired together

and

a 200mm concrete topping.

Marking the diffuser was essential, being in a busy area for both commercial

and

leisure craft.

Anglian Marine Services

and

Haven Ports Ltd utilising their jack-up barge Haven Seaway, assisted by Felixarc Marine’s multi-cat Gray Mammoth, installed a fixed structure in the form of a steel triangular dolphin

with

sides approximately 5m in length. The whole structure is around 18m high

and

comprises three sections connected by conical spurs

and

sockets in each section. The two lower sections are embedded

with

in the pit

with

three short lengths emerging from the pit fill to which the main upper section is attached.

The northernmost leg has a double fabricated fender

with

bump stops protecting a vertical ladder providing access to the maintenance platform

and

safety cage at the very top of the structure, 6.2m above Ordnance Datum Newlyn

and

3.9m above MHWS. Lowestoft based Pelangi International provided the required navigational marks comprising top mark, radar reflector

and

a solar powered light

and

battery.

By Peter Barker