Abstract: Downtime due to adverse wave conditions for vessels at berth is an important commercial aspect in the planning and development of a sea port or a berthing terminal。 This paper describes a practical technique for preliminary assessment of operational downtime at a proposed bulk terminal。 Time-series wind and wave data at an offshore location was purchased。 Numerical modelling was then carried out using the MIKE21 SW (spectral wave) model developed by DHI (Deutsches Hydrographisches Institut) to transform these offshore waves into inshore in order to derive wave conditions at the berth。 Both wind-waves and swell-waves were considered。  Waves  affecting the head  and beam  of a vessel  were  considered  separately for a wide range  of vessel  sizes with DT(displacement tonnage) ranging from 5,000 tons  to The limiting wave height H,•。 was used。 Operational  downtime

was also calculated using significant wave heigbt, Hs as a criterion with limits of Hs —— I 。0 in for beam seas and Hs —— 1。5 in for head seas。 The methodology and lessons learnt from the study can be applied for the development of any sea port worldwide。 80362

Key words: Numerical modelling, wave propagation, wave transformation, downtime, port planning, bulk terminal。

1。 Introduction

Large scale bulk terminals are of critical importance to the seabome trade and transportation of dry bulk commodities such as crude oil, iron ore, coal, grain, bauxite, alumina and rock phosphate。 Bulk commodities which are those loaded or discharged in loose or fluid form account for the biggest share of the world seaborne trade。 Crude oil and petroleum products are tanker cargoes while iron ore, coal, grains, bauxite, alumina and rock phosphate constitute the main dry bulk cargoes and are referred to as the major dry bulks。 They are traded in large quantities and shipped almost exclusively in specialised bulk carriers of different sizes ranging from handy sized (10,000-55,000 dwt) to large specialised ships of > 200,000 dwt。

Bulk terminals have become one of the

Corresponding author: Md Akhtaruzzaman Sarker, senior engineer, research field: numerical modelling of coastal processes。 E-mail: zaman。sarker@rhdhv。com。

well-established features  in  international  seabome trade。 Such terminals  may  simply  have  an  anchorage or a berth or include items such as dredging and breakwaters。 As a minimum, a bulk terminal comprises a berthing facility for loading or unloading ships and marine works for the safe access and operation of ships。 Operational downtime due to adverse wave conditions for loading and unloading of vessels at berth is an important technical and commercial aspect in the planning and development of a bulk  terminal  or a port。

This paper describes a practical technique for the preliminary assessment of operational downtime at a proposed dry bulk terminal。 As part of the assessment process, numerical modelling of wave transformation was carried out using the MIKE2I SW (spectral wave) model developed by DHI  (Deutsches Hydrographisches Institut) to derive inshore wave conditions at the bulk terminal [1)。 Operational downtime   due  to  wind-waves   and   swell-waves  was