基于螺旋桨轴径判断渔船的“大机小标”现象

Phenomenon of actual engine power higher than rated power in nameplate based on the propeller shaft diameter of fishing vessel

本研究旨在探索一种简便易行的方法,用于初步判断渔船是否存在"大机小标"现象,且能提前判别新造船螺旋桨轴径的选取是否私下改装从而增加主机功率的可能性。通过研究典型主机改装前后的标定功率、转速和规范对螺旋桨轴径要求的最小值之间的关系,以及螺旋桨轴径的实取裕量与轴系设计手册推荐裕量之间的关系,得出轴径的实际取值的合理性与"大机小标"之间存在一定关联性,从而提出通过测量螺旋桨轴径和实船额定转速初步判断"大机小标"的方法。对现存渔船可以先用此方法筛选,如有必要再进行实船的功率测量,可以大量节省检验成本。对于新造渔船,该方法可在审图阶段作为发现"大机小标"的重要判断指标,控制螺旋桨轴径裕量可以在一定程度上增加违法改装成本,从而减少"大机小标"现象,规范渔机市场,进一步完善渔船规则规范,使得国家的双控政策得以更好地实施。

The purpose of this article was to explore a simple method for preliminarily judging the phenomenon that ＂ actual power of fishing vessel engine was higher than rated power in nameplate＂ , and preliminarily discovering the possibility whether a new ship＇s propeller shaft diameter foreshadowed increases the actual power of main engine by in- stalling fake plate or remoulding engine. By means of studying the relationship of nominal power, rotational speed and the minimum allowable value of the propeller diameter in rules, and the relationship between actual allowance of pro- peller shaft diameter, the allowance recommended by the shaft design manual, it drew that there was certain correla- tion between the reasonableness of actual value of shaft diameter and the phenomenon of ＂actual power higher than the rated power＂ , thereby proposed the method for preliminary judging ＂actual power higher than rated power＂ by meas- uring the propeller shaft diameter and rotational speed. The existing fishing vessels can be screened in this way, if necessary, we could based on facts by measuring engine actual shaft power further, therefore it would save so much inspecting costs. It played a part as well as new fishing vessels, which could discover the phenomenon of ＂ actual pow- er higher than rated power＂ at the stage of drawing approval. The control of the propeller shaft diameter margin can increase the costs of illegal remoulding very much, so that it would reduce the phenomenon of ＂ actual power higher than rated power＂ , and it would make the fishing machine market more formal, and it would make the implement of the dual- control policy effectively in China.