839:
987:
31:
677:. This consisted of a wooden panel, attached by line to a reel, and weighted on one edge to float perpendicularly to the water surface and thus present substantial resistance to the water moving around it. The chip log was cast over the stern of the moving vessel and the line allowed to pay out.
1282:
Since the 1890s or thereabouts, it has been drummed into the young seaman that a knot is a unit of speed, namely, one nautical mile per hour; and that consequently only the uneducated speak of "knots per hour" or "knots an hour". It was therefore inevitable that
Kipling's frequent use of this
876:, of the sort on many maps, would therefore be useless on such a chart. Since the length of a nautical mile, for practical purposes, is equivalent to about a minute of latitude, a distance in nautical miles on a chart can easily be measured by using
788:
903:
specified that distances were to be in statute miles, and speeds in miles per hour. In 1969, these standards were progressively amended to specify that distances were to be in nautical miles, and speeds in knots.
1119:
International
Standards and Recommended Practices, Annex 5 to the Convention on International Civil Aviation, "Units of measurement to be Used in Air and Ground Operations", ICAO, 4th Edition, July 1979.
828:
872:, the horizontal (East–West) scale varies with latitude. On a chart of the North Atlantic, the scale varies by a factor of two from Florida to Greenland. A single
808:
731:
1099:
1140:
887:
Speed is sometimes incorrectly expressed as "knots per hour", which would mean "nautical miles per hour per hour" and thus would refer to
1145:
The knot is defined as one nautical mile per hour. There is no internationally agreed symbol, but the symbol kn is commonly used.
697:(28-second sand-glass is the currently accepted timing) to time the operation. The knot count would be reported and used in the
1158:
1236:
1060:
961:
The indicated airspeed is close to the true airspeed only at sea level in standard conditions and at low speeds. At
850:
does not fit within the SI system, its retention for nautical and aviation use is important because the length of a
723:
inches per second or 1.85166 kilometres per hour. The difference from the modern definition is less than 0.02%.
975: ft), an indicated airspeed of 300 kn may correspond to a true airspeed of 500 kn in standard conditions.
50:
646:
250:
900:
862:
1026:
865:. As a result, nautical miles and knots are convenient units to use when navigating an aircraft or ship.
1333:
1081:
1283:
expression should grieve a number of seafaring readers, as the pages of the
Kipling Journal testify.
338:). The UK adopted the international nautical mile definition in 1970, having previously used the UK
330:. The US adopted the international definition in 1954, having previously used the US nautical mile (
1338:
1228:
1132:
1304:
693:) from each other, passed through a sailor's fingers, while another sailor used a 30-second
1294:
For example, Part 23 of the
Federal Aviation Regulations, amendment 23–7, 14 September 1969
813:
266:
8:
1328:
1095:
1008:, which deals with theoretical estimates of practical maximum speed of displacement hulls
947:
936:
927:
869:
446:
376:
115:
793:
930:
923:
838:
662:
258:
36:
1232:
1221:
1133:"Non-SI units accepted for use with the SI, and units based on fundamental constants"
1056:
954:
951:
339:
907:
The following abbreviations are used to distinguish between various measurements of
842:
Graphic scale from a
Mercator projection world map, showing the change with latitude
1021:
992:
399:
371:
184:
147:
1270:
1195:
881:
877:
582:
391:
163:
241:
is also common, especially in aviation, where it is the form recommended by the
1266:
1000:
940:
899:
Prior to 1969, airworthiness standards for civil aircraft in the United States
702:
698:
494:
381:
131:
1169:
1322:
916:
851:
650:
642:
641:) are measured in knots. For consistency, the speeds of navigational fluids (
290:
270:
206:
783:{\displaystyle 1~{\textrm {kn}}=1852~{\textrm {m/h}}=0.5144~{\textrm {m/s}}}
1016:
986:
888:
873:
658:
1031:
682:
254:
222:
1011:
1005:
706:
654:
855:
694:
673:
Until the mid-19th century, vessel speed at sea was measured using a
638:
30:
1166:
Weights and
Measures Standards of the United States, A brief history
1156:
908:
859:
674:
274:
262:
880:
and the latitude scales on the sides of the chart. Recent
British
661:(GS) in aircraft) and rate of progress towards a distant point ("
884:
have a latitude scale down the middle to make this even easier.
657:) are also measured in knots. Thus, speed over the ground (SOG;
690:
634:
202:
75:
686:
678:
294:
246:
242:
234:
230:
919:", the airspeed of an aircraft relative to undisturbed air
854:, upon which the knot is based, is closely related to the
322:
The length of the internationally agreed nautical mile is
190:
265:
navigation. A vessel travelling at 1 knot along a
816:
796:
734:
187:
982:
193:
1220:
822:
802:
782:
231:Institute of Electrical and Electronics Engineers
1320:
1100:International Organization for Standardization
1193:
1159:"Appendix 4 The international nautical mile"
1157:Louis E. Barbow and Lewie V. Judson (1976).
1141:International Bureau of Weights and Measures
709:. This method gives a value for the knot of
315:20.25372 inches per second (approximately)
309:0.51444 metres per second (approximately),
29:
1223:The Oxford Companion to Ships and the Sea
1187:
1168:. NIST Physics Laboratory. Archived from
950:", the calibrated airspeed corrected for
363:Conversions between common units of speed
243:International Civil Aviation Organization
1075:
939:", the indicated airspeed corrected for
837:
318:1.68781 feet per second (approximately).
1258:
1200:. DeWolfe, Fiske, & Co., Publishers
1127:
1125:
1055:(first ed.). Osprey. p. 173.
312:1.15078 miles per hour (approximately),
1321:
1264:
637:in which they travel (boat speeds and
633:The speeds of vessels relative to the
229:. The same symbol is preferred by the
1050:
894:
1218:
1122:
926:", the speed shown on an aircraft's
1227:. Oxford University Press. p.
1150:
868:On a standard nautical chart using
13:
14:
1350:
1265:Wilson, Alastair (22 July 2009).
665:", VMG) are also given in knots.
985:
183:
1297:
1288:
1253:Puerto de Huelva and Approaches
1245:
1212:
1113:
1088:
1069:
1044:
681:tied at a distance of 47
280:
1:
1037:
833:
726:Derivation of knots spacing:
1076:Bartlett, Tim (July 2008) .
901:Federal Aviation Regulations
863:geographic coordinate system
39:, which shows speed in knots
7:
1305:"Abbreviations and symbols"
1027:Orders of magnitude (speed)
978:
957:for the particular altitude
10:
1355:
1082:Royal Yachting Association
306:metres per hour (exactly),
269:travels approximately one
253:unit. The knot is used in
1219:Kemp, Peter, ed. (1976).
668:
625:(* = approximate values)
159:
143:
127:
111:
107:
89:
81:
71:
49:
44:
28:
23:
1053:A Dictionary of Aviation
1051:Wragg, David W. (1973).
628:
1078:RYA Navigation Handbook
225:symbol for the knot is
1309:edocket.access.gpo.gov
843:
824:
804:
784:
286:1 international knot =
1197:Rollo on the Atlantic
1194:Jacob Abbott (1858).
1137:SI brochure (8th ed.)
841:
825:
823:{\displaystyle 14.40}
805:
785:
249:). The knot is a non-
1175:on 26 September 2007
943:and instrument error
814:
794:
732:
1271:The Kipling Society
948:equivalent airspeed
937:calibrated airspeed
870:Mercator projection
365:
102:... is equal to ...
45:General information
1251:E.g. BA Chart 73,
1096:"ISO 80000-3:2006"
931:airspeed indicator
924:indicated airspeed
895:Aeronautical terms
846:Although the unit
844:
820:
803:{\displaystyle 28}
800:
780:
663:velocity made good
361:
209:per hour, exactly
169:
161:
153:
145:
137:
129:
121:
113:
37:airspeed indicator
1334:Units of velocity
1267:"'Knots an hour'"
955:compressible flow
830:metres per knot.
777:
772:
761:
756:
745:
740:
623:
622:
175:
174:
90:Conversions
1346:
1313:
1312:
1301:
1295:
1292:
1286:
1285:
1279:
1277:
1262:
1256:
1249:
1243:
1242:
1226:
1216:
1210:
1209:
1207:
1205:
1191:
1185:
1184:
1182:
1180:
1174:
1163:
1154:
1148:
1147:
1129:
1120:
1117:
1111:
1110:
1108:
1106:
1092:
1086:
1085:
1073:
1067:
1066:
1048:
1022:Metre per second
995:
993:Transport portal
990:
989:
974:
973:
967:
966:
882:Admiralty charts
829:
827:
826:
821:
810:seconds that is
809:
807:
806:
801:
789:
787:
786:
781:
779:
778:
775:
770:
763:
762:
759:
754:
747:
746:
743:
738:
722:
721:
717:
714:
615:
614:
606:
605:
598:
597:
590:
575:
574:
563:
562:
551:
550:
533:
532:
524:
523:
513:
512:
505:
504:
487:
486:
478:
477:
469:
468:
457:
456:
439:
438:
430:
429:
421:
420:
413:
412:
366:
364:
360:
357:
355:
349:
347:
337:
335:
329:
327:
305:
304:
297:(by definition),
220:
216:
212:
200:
199:
196:
195:
192:
189:
170:
162:
154:
146:
138:
130:
122:
114:
33:
21:
20:
1354:
1353:
1349:
1348:
1347:
1345:
1344:
1343:
1339:Water transport
1319:
1318:
1317:
1316:
1303:
1302:
1298:
1293:
1289:
1275:
1273:
1263:
1259:
1250:
1246:
1239:
1217:
1213:
1203:
1201:
1192:
1188:
1178:
1176:
1172:
1161:
1155:
1151:
1131:
1130:
1123:
1118:
1114:
1104:
1102:
1094:
1093:
1089:
1080:. Southampton:
1074:
1070:
1063:
1049:
1045:
1040:
991:
984:
981:
971:
969:
964:
962:
922:KIAS is "knots
897:
836:
815:
812:
811:
795:
792:
791:
774:
773:
758:
757:
742:
741:
733:
730:
729:
719:
715:
712:
710:
671:
631:
612:
610:
603:
601:
595:
593:
588:
572:
570:
560:
558:
548:
546:
530:
528:
521:
519:
510:
508:
502:
500:
484:
482:
475:
473:
466:
464:
454:
452:
436:
434:
427:
425:
418:
416:
410:
408:
362:
353:
351:
345:
343:
342:nautical mile (
333:
331:
325:
323:
302:
300:
283:
218:
214:
213:(approximately
211:1.852 km/h
210:
201:) is a unit of
186:
182:
168:
160:
152:
144:
136:
128:
120:
112:
67:
40:
17:
12:
11:
5:
1352:
1342:
1341:
1336:
1331:
1315:
1314:
1296:
1287:
1257:
1244:
1237:
1211:
1186:
1149:
1121:
1112:
1087:
1068:
1061:
1042:
1041:
1039:
1036:
1035:
1034:
1029:
1024:
1019:
1014:
1009:
1003:
1001:Beaufort scale
997:
996:
980:
977:
959:
958:
946:EAS is "knots
944:
941:position error
935:CAS is "knots
933:
920:
915:TAS is "knots
896:
893:
835:
832:
819:
799:
769:
766:
753:
750:
737:
703:dead reckoning
699:sailing master
689:(14.4018
670:
667:
651:river currents
643:ocean currents
630:
627:
621:
620:
617:
608:
599:
591:
586:
578:
577:
568:
565:
556:
553:
544:
536:
535:
526:
517:
514:
506:
498:
490:
489:
480:
471:
462:
459:
450:
442:
441:
432:
423:
414:
406:
403:
395:
394:
389:
384:
379:
374:
369:
320:
319:
316:
313:
310:
307:
298:
287:
282:
279:
273:of geographic
219:0.514 m/s
215:1.151 mph
173:
172:
166:
157:
156:
150:
141:
140:
134:
125:
124:
118:
109:
108:
105:
104:
99:
92:
91:
87:
86:
83:
79:
78:
73:
69:
68:
66:
65:
62:
59:
55:
53:
47:
46:
42:
41:
34:
26:
25:
15:
9:
6:
4:
3:
2:
1351:
1340:
1337:
1335:
1332:
1330:
1327:
1326:
1324:
1310:
1306:
1300:
1291:
1284:
1272:
1268:
1261:
1254:
1248:
1240:
1238:0-19-282084-2
1234:
1230:
1225:
1224:
1215:
1199:
1198:
1190:
1171:
1167:
1160:
1153:
1146:
1142:
1138:
1134:
1128:
1126:
1116:
1101:
1097:
1091:
1083:
1079:
1072:
1064:
1062:9780850451634
1058:
1054:
1047:
1043:
1033:
1030:
1028:
1025:
1023:
1020:
1018:
1015:
1013:
1010:
1007:
1004:
1002:
999:
998:
994:
988:
983:
976:
956:
953:
949:
945:
942:
938:
934:
932:
929:
925:
921:
918:
917:true airspeed
914:
913:
912:
910:
905:
902:
892:
890:
885:
883:
879:
875:
874:graphic scale
871:
866:
864:
861:
857:
853:
852:nautical mile
849:
840:
831:
817:
797:
767:
764:
751:
748:
735:
727:
724:
708:
704:
700:
696:
692:
688:
684:
680:
676:
666:
664:
660:
656:
652:
648:
647:tidal streams
644:
640:
636:
626:
618:
609:
600:
592:
587:
584:
580:
579:
569:
566:
557:
554:
545:
542:
538:
537:
527:
518:
515:
507:
499:
496:
492:
491:
481:
472:
463:
460:
451:
448:
444:
443:
433:
424:
415:
407:
404:
401:
397:
396:
393:
390:
388:
385:
383:
380:
378:
375:
373:
370:
368:
367:
359:
341:
317:
314:
311:
308:
299:
296:
292:
291:nautical mile
288:
285:
284:
278:
277:in one hour.
276:
272:
268:
264:
260:
256:
252:
248:
244:
240:
236:
232:
228:
224:
208:
207:nautical mile
205:equal to one
204:
198:
180:
167:
165:
158:
151:
149:
142:
135:
133:
126:
119:
117:
110:
106:
103:
100:
98:
94:
93:
88:
84:
80:
77:
74:
70:
63:
60:
57:
56:
54:
52:
48:
43:
38:
32:
27:
22:
19:
16:Unit of speed
1308:
1299:
1290:
1281:
1274:. Retrieved
1260:
1252:
1247:
1222:
1214:
1202:. Retrieved
1196:
1189:
1177:. Retrieved
1170:the original
1165:
1152:
1144:
1136:
1115:
1103:. Retrieved
1090:
1077:
1071:
1052:
1046:
1017:Knotted cord
960:
928:pitot-static
906:
898:
889:acceleration
886:
867:
847:
845:
728:
725:
672:
659:ground speed
632:
624:
540:
386:
321:
238:
226:
223:ISO standard
178:
176:
101:
96:
85:kn, kt
72:Unit of
18:
1204:30 November
1032:Rope (unit)
655:wind speeds
356:.184 m
336:.248 m
281:Definitions
255:meteorology
58:meteorology
51:Unit system
1329:Navigation
1323:Categories
1276:1 December
1038:References
1012:Knot count
1006:Hull speed
834:Modern use
707:navigation
695:sand-glass
639:air speeds
583:fps (ft/s)
495:mph (mi/h)
392:fps (ft/s)
382:mph (mi/h)
95:1 kn
968: m (
952:adiabatic
856:longitude
340:Admiralty
257:, and in
237:), while
1179:2 August
979:See also
909:airspeed
878:dividers
860:latitude
790:, so in
675:chip log
348: ft
275:latitude
267:meridian
259:maritime
155:0.514444
64:maritime
61:aviation
1105:20 July
718:⁄
685:3
328: m
303:852.000
289:1
221:). The
171:1.68781
139:1.15078
1255:, 2002
1235:
1059:
771:
768:0.5144
755:
739:
687:inches
669:Origin
635:fluids
589:0.3048
271:minute
97:in ...
82:Symbol
1173:(PDF)
1162:(PDF)
818:14.40
679:Knots
629:Usage
611:0.592
602:0.681
594:1.097
571:1.687
559:1.150
555:1.852
547:0.514
529:1.466
520:0.868
509:1.609
501:0.447
483:0.911
474:0.539
465:0.621
453:0.277
435:3.280
426:1.943
417:2.236
409:3.600
203:speed
123:1.852
76:speed
1278:2012
1233:ISBN
1206:2011
1181:2007
1107:2013
1057:ISBN
848:knot
752:1852
705:and
683:feet
653:and
541:knot
447:km/h
387:knot
377:km/h
295:hour
293:per
261:and
247:ICAO
235:IEEE
179:knot
177:The
164:ft/s
116:km/h
24:knot
1229:454
972:000
965:000
776:m/s
760:m/h
701:'s
613:484
604:818
573:810
561:779
549:444
531:667
522:976
511:344
485:344
476:957
467:371
455:778
437:840
428:844
419:936
411:000
400:m/s
372:m/s
358:).
354:853
350:or
346:080
334:853
326:852
263:air
217:or
148:m/s
132:mph
35:An
1325::
1307:.
1280:.
1269:.
1231:.
1164:.
1143:.
1139:.
1135:.
1124:^
1098:.
970:36
963:11
911::
891:.
798:28
744:kn
711:20
649:,
645:,
619:1
596:28
585:=
581:1
576:*
543:=
539:1
534:*
503:04
497:=
493:1
488:*
449:=
445:1
440:*
402:=
398:1
251:SI
239:kt
227:kn
1311:.
1241:.
1208:.
1183:.
1109:.
1084:.
1065:.
858:/
765:=
749:=
736:1
720:4
716:1
713:+
691:m
616:*
607:*
567:1
564:*
552:*
525:*
516:1
479:*
470:*
461:1
458:*
431:*
422:*
405:1
352:1
344:6
332:1
324:1
301:1
245:(
233:(
197:/
194:t
191:ɒ
188:n
185:/
181:(
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
