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[规范类] 船首最小吃水确定的依据和方法

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发表于 2013-3-16 20:56 | 显示全部楼层 |阅读模式 来自: 中国湖南衡阳

艉吃水涉及螺旋桨浸没,LL有对最小船首高度的要求。但船首最小吃水确定的依据和方法是什么??
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龙船学院
发表于 2013-3-16 22:14 | 显示全部楼层 来自: 中国江苏
反抨击,船长百分比
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发表于 2013-3-17 00:45 | 显示全部楼层 来自: 中国辽宁盘锦
本帖最后由 BRACKET 于 2013-3-17 00:54 编辑

Regulation 39 - Minimum bow height and reserve buoyancy
(1). The bow height (Fb), defined as the vertical distance at the forward perpendicular between the waterline corresponding to the assigned summer freeboard and the designed trim and the top of the exposed deck at side, shall be not less than:
[img]mkMSITStore:C:\Program%20Files\Lloyd's%20Register\Rulefinder\9.15\Rulefinder_STAT.chm::/equatn73.gif[/img]

where:
Fb is the calculated minimum bow height, in mm;

L is the length, as defined in [url=mkMSITStore:C:\Program%20Files\Lloyd]regulation 3[/url], in m;

B is the moulded breadth, as defined in [url=mkMSITStore:C:\Program%20Files\Lloyd]regulation 3[/url], in m;

d1 is the draught at 85% of the least moulded depth, in metres;

Cb is the block coefficient, as defined in [url=mkMSITStore:C:\Program%20Files\Lloyd]regulation 3[/url];

Cwf is the waterplane area coefficient forward of L/2: Cwf = Awf/ {(L/2) x B};

Awf is the waterplane area forward of L/2 at draught d1, in m2.



. For ships to which timber freeboards are assigned, the summer freeboard (and not the timber summer freeboard) is to be assumed when applying paragraph (1).

(2). Where the bow height required in paragraph (1) is obtained by sheer, the sheer shall extend for at least 15% of the length of the ship measured from the forward perpendicular. Where it is obtained by fitting a superstructure, such superstructure shall extend from the stem to a point at least 0.07L abaft the forward perpendicular, and shall be enclosed as defined in [url=mkMSITStore:C:\Program%20Files\Lloyd]regulation 3(10)[/url].

(3). Ships which, to suit exceptional operational requirements, cannot meet the requirements of paragraphs (1) and (2) of this regulation may be given special consideration by the Administration.

(4).
(a). The sheer of the forecastle deck may be taken into account, even if the length of the forecastle is less than 0.15L, but greater than 0.07L, provided that the forecastle height is not less than one half of standard height of superstructure as defined in [url=mkMSITStore:C:\Program%20Files\Lloyd]regulation 33[/url] between 0.07L and the forward perpendicular.

(b). Where the forecastle height is less than one half of the standard height of superstructure, as defined in [url=mkMSITStore:C:\Program%20Files\Lloyd]regulation 33[/url], the credited bow height may be determined as follows:
(i). Where the freeboard deck has sheer extending from abaft 0.15L, by a parabolic curve having its origin at 0.15L abaft the forward perpendicular at a height equal to the midship depth of the ship, extended through the point of intersection of forecastle bulkhead and deck, and up to a point at the forward perpendicular not higher than the level of the forecastle deck (as illustrated in [url=mkMSITStore:C:\Program%20Files\Lloyd]figure 39.1[/url]). However, if the value of the height denoted ht in [url=mkMSITStore:C:\Program%20Files\Lloyd]figure 39.1[/url] is smaller than the value of the height denoted hb then ht may be replaced by hb in the available bow height.

(ii). Where the freeboard deck has sheer extending for less than 0.15L or has no sheer, by a line from the forecastle deck at side at 0.07L extended parallel to the base line to the forward perpendicular (as illustrated in [url=mkMSITStore:C:\Program%20Files\Lloyd]figure 39.2[/url]).



Figure 39.1


Figure 39.2
hf = Half standard height of superstructure as defined in regulation 33.


(5). All ships assigned a type ’B’ freeboard, other than oil tankers see footnote , chemical tankers see footnote and gas carriers see footnote , shall have additional reserve buoyancy in the fore end. Within the range of 0.15L abaft of the forward perpendicular, the sum of the projected area between the summer load waterline and the deck at side (A1 and A2 in figure 39.3) and the projected area of an enclosed superstructure, if fitted, (A3) shall not be less than:


where:
Fmin is calculated by: Fmin = (F0 × f1) + f2;

F0 is the tabular freeboard, in mm, taken from table 28.2, corrected for regulation 27(9) or 27(10), as applicable;

f1 is the correction for block coefficient given in regulation 30; and

f2 is the correction for depth, in mm, given in regulation 31.



Figure 39.3
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发表于 2013-3-17 00:50 | 显示全部楼层 来自: 中国辽宁盘锦
原来是LL的,晕倒,我还以为是装在手册的
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发表于 2013-3-17 09:10 | 显示全部楼层 来自: 中国江苏南通
如果是轴系校中的浮态,瓦锡兰的要求是,15万吨以下的船舶,桨毂完全浸没水中。船首吃水没有要求。
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发表于 2013-3-17 09:11 | 显示全部楼层 来自: 中国天津
好东西,怎么看不到图啊
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 楼主| 发表于 2013-3-18 20:03 | 显示全部楼层 来自: 中国浙江湖州
3楼给的是最小船首高度的要求,对于船首最小吃水,只记得跟驾驶台视野、首部抨击、首部应急消防泵有关。尾部对螺旋桨浸水深度、消防泵有关。
不记得是哪的要求了,求解
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