曝光台 注意防骗
网曝天猫店富美金盛家居专营店坑蒙拐骗欺诈消费者
In particular when under tow, the legs will be elevated to their maximum height and, as a result, they will be the dominant obstructions. This should be taken fully into account during helideck design.
Vessels
Similar to semi-submersibles, vessels require their helideck designs to take fully into account the additional measures needed to accommodate vessel movements, as noted previously. Much will depend on the location of the helideck on the vessel and the ability of the vessel to manoeuvre in order to gain favourable wind flows over the helideck during helicopter operations.
A Drill Ship featuring a vessel type hull may be typically moored using a conventional widely spread anchor system. Alternatively, it may be dynamically positioned (DP).
Conventional anchoring means there is little, if any, scope for changing the helideck position relative to favourable windflows once the anchor pattern is set. DP may allow the vessel some heading adjustment into the prevailing wind, wave and current conditions, dependent entirely on drilling and marine safety priorities.
A forward mounted helideck, either mounted on the foredeck or elevated above the bridge, presents the biggest problems for a helicopter pilot. This is because there are very few, if any, visual cues available to assist the pilot in making a safe approach and landing. Taking-off is less of a problem.
The lack of visual cues means that manoeuvring space provided for the helicopter has to take greater account of the proximity of all likely obstructions. To do this, and in order to prevent inadvertent tail rotor strikes, the helideck and safe landing area layout should be very carefully designed to obtain maximum operating clearances – see Figure 7.2. (See also CAP 437).
Important naval architecture considerations to be made when designing a forward mounted helideck are:
.
A large and therefore heavy helideck structure elevated above the bridge may adversely affect vessel stability
.
A large foredeck mounted helideck (below bridge level) that overhangs the vessel bow will obscure the vessel forward section from the bridge, thus severely reducing visual references for manoeuvring the vessel when coming alongside
.
A helideck integral with the Foredeck may have the advantage of two access and escape routes toward the rear of the helideck past the natural protection afforded by the bridge structure. However, providing a third means of escape forward will invariably require a forward hatch to below deck. This hatch may constitute a structural ‘soft spot’ and should be regarded as a restricted approach and landing sector which will then require suitable markings to inform the helicopter pilot.
7.2.3.6 Materials of Construction
It should be noted that where aluminium is chosen for the helideck construction, and the vessel is to be constructed to comply with SOLAS, then reference should be made to SOLAS Chapter II -2 Regulation 18.8 [Ref: 71].
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：离岸直升机起落甲板设计指南 OFFSHORE HELIDECK DESIGN GUIDELINES 1(35)
