Page 9: of Maritime Reporter Magazine (October 2010)

A 320.3 ft., three-legged liftboat has been designed by

A. K. Suda, Inc. for SEMCO. The jacking system, elec- trical and automation design has been done by SEMCO.

The vessel will, when completed receive ABS MODU

Restricted Service certification as well as USCG Sub- chapter I-A/L.

Suda designs are generally considered robust, in that the component and parameter selection is optimized to avoid unnecessary spare (unusable) capacity of any component.

For example, the legs do not have to be twice as strong as the jacking system capacity. This design is no different.

Notice the depth of merely 14 feet, no more than is ab- solutely necessary to provide a strong, stable and efficient working platform. The saving in hull weight benefits the leg and jacking system design which in turn, improves variable load carrying capacity.

Smaller vessels have larger depths. The leg design boasts of a lower weight per foot, based on comparable designs in the industry, while still meeting or exceeding all design factors of safety based on class and other stan- dards. The designer believes that this is the largest dwt/displacement ratio (a measure of merit in ROI) ves- sel of its type. The selection of the parameters is comple- mented by a streamlined deep chine form with a complementing bowthruster pod. One of the secrets of success is the working relationship, not only between the yard and the designer, but also with SEATRAX, the de- signer and manufacturer of the behemoth cranes. The uniqueness of these cranes lies in their patented design and ease of operation, wrapped around the forward legs.

This helps to provide an even larger unobstructed work- ing area than would have been possible with a vessel of this size. The design parameters allow this vessel to not only work as an oil exploration support services vessel, but also in wind energy support services. The vessel can carry components of an entire windmill at a time.

NEWS FEATURE VESSEL

Semco 320-ft. Leg Liftboat

Main Particulars

Hull length, o.a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .195 ft.

Hull beam molded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .129 ft.

Hull depth molded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 ft.

Leg diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9.5 ft.

Leg length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .320 ft.

Open deck space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14,230 sq. ft.

Environmental condition elevated – Normal Operations

Max. Water depth (includes tides) . . . . . . . . . . . . . . . . . . . . . . . . . . . .250 ft.

Wave height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 ft.

Wave period (max.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8.5 second

Wind velocity (1 minute) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70 knots

Current (surface) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.5 knots

Current (Mudline) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 knots

Air gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 ft.

Leg penetration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0 to 10 ft.

Environmental condition elevated – Survival Conditions

Max. Water depth (includes tides) . . . . . . . . . . . . . . . . . . . . . . . . . . . .140 ft.

Wave height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 ft.

Wave period (max.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 second

Wind velocity (1 minute) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 knots

Current (surface) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 knots

Air gap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 ft.

Leg penetration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0-10 ft.

Capacities

Fuel storage tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43,400 gal.

Fuel day tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4,300 gal.

Fresh water tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67,290 gal.

Lube oil tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1,250 gal.

Hydraulic oil tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5,000 gal.(portable)

Waste oil tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2,000 gal.

Oily water bilge tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5,000 gal.

Buffer Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2,450 gal.

Tonnage (International) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3,163

Accommodations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100

Power to Props (total) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4,600 BHP

Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ABS

A 320.3 ft., three-legged liftboat has been designed by A. K. Suda, Inc. for SEMCO. The vessel will, when completed receive ABS MODU Restricted Service certification as well as USCG Subchapter I-A/L.