Supplementary propulsion systems
輔助推進系統(tǒng)

The efficiency of conventional well-designed propulsion arrangements range 50 - 70% as illustrated in Figure 5-8. The theoretical propulsive efficiency for a given propulsor load (thrust/area ratio) is typically in the range 50 - 97%. Thus, the theoretical maximum gain is in most cases limited to less than 20%, sometimes a bit more if it is possible to increase the propulsor working area (“propeller diameter”) significantly. It should be noted that the theoretical maximum assumes no energy loss in the process of transforming the mechanical energy from the engine into momentum increase of the water, something that is not very realistic.
傳統(tǒng)精心設計的推進安排范圍50 - 70％的效率，如圖5-8所示。對于一個給定的推進器的負載（推力/面積比）的理論推進效率一般是在范圍為50 - 97％。因此，理論上的最大增益在大多數(shù)限于小于20％的情況下，有時會多一點，如果它是可以顯著增加推進器的工作區(qū)（“螺旋槳直徑”）。應該指出的是理論上的最大值假定在從發(fā)動機的機械能轉化成水的動量增加的過程中，沒有能量損失，這是不太現(xiàn)實的。

Figure 5-8 - Propulsive efficiency of different propulsion systems
圖5-8 - 不同的推進系統(tǒng)推進效率

It is clear that there is limited room for innovative solutions to revolutionise ship propulsion. There have been some original inventions over the years, like the Whale Tail Propulsion systemand different versions of the paddle wheel. The possible advantage of those systems is that they apply a relatively larger propulsion area. Thus, they have a higher theoretical efficiency.
很清楚，創(chuàng)新的解決方案，徹底改變船舶推進的空間有限。多年來，已經(jīng)有一些原創(chuàng)性發(fā)明，像鯨尾推進系統(tǒng)和不同版本的槳輪。這些系統(tǒng)的可能的優(yōu)點是，它們適用于一個相對較大的推進區(qū)。因此，它們具有更高的理論效率。

However, they are mechanically more complex than the screw propeller, which adds weight and increase mechanical losses. The paddle wheels also have a lower efficiency converting mechanical energy into thrust. It seems unlikely that any of these inventions will have any impact on the energy consumption of the world fleet.
然而，他們是機械復雜得多的螺旋推進器，這增加了重量，并增加機械損失。該葉輪也有一個較低的效率，機械能轉化為推力。這似乎不大可能，這些發(fā)明將在世界船隊中的能量消耗沒有任何影響。

In the seventies and eighties there were several attempts to use sails and wind power as supplementary propulsion on fairly large merchant vessels. While upwards of 25 vessels, from
50 to 50,000 tons have either been retrofitted or studied for sail retrofit [Bergeson and Greenwald, 1982   #p#分頁標題#e#http://ukthesis.org/ygsslwdx/  ; Priebe, 1986], there is little or no commercial interest in sails as supplementary propulsion today. The reason for this is the same as it was 100 years ago; fuel oil is inexpensive, powered vessels are not labour intensive and powered vessels' performance is both reliable and repeatable. Currently envisioned concepts for sails as supplementary propulsion result in average fuel savings throughout a vessel's voyage on the order of 10-30% [Bergeson and Greenwald, 1982; MacAlister, 1982]. With anything near the current bunker price, this is not enough saving to warrant the investment, additional maintenance and crew requirements, as well as the restrictions the sailing gear will put on the use of deck space.
在七十年代和八十年代，有幾個嘗試使用帆和風力發(fā)電作為補充相當大的商船上推進。雖然只有25艘船舶，從50噸至50,000噸以上被改裝或研究帆改造[Bergeson和格林沃爾德，1982年PRIEBE，1986]，很少或沒有商業(yè)利益帆今天作為補充推進。這樣做的原因是一樣的，因為在100年前，燃料油價格低廉，馬力船只不是勞動密集和動力船只，性能是可靠和可重復的。

Wave propulsion is another supplementary propulsion system, where fixed or movable foils in the bow region provides a thrust produced by the vertical motion of the bow relative to the surrounding waves. This concept works well as long as the relative vertical motions are large, which is the case for relatively small vessels moving in head seas of suitable length and height.
波推進器是另一種輔助推進系統(tǒng)，其中在船頭區(qū)域，固定的或可移動的金屬箔提供了一個推力，所產(chǎn)生的垂直運動相對于周圍的波弓。這個概念運作良好，只要相對垂直運動很大，這是合適的長度和高度的頭海域移動的情況下，相對較小的船只。

Thus, the number of ships where this concept would be applicable is small, and the gain for those ships is also small, since the period of time when the wave conditions are suitable is small.
因此，這個概念將適用于小的船舶數(shù)量，這些船舶的收益也小，因為波條件適合時，時間也是短的。