Explorers

TECHNICAL LIBRARY

GENERAL ITEMS

WIRE ROPE STRENGTHS

1X19 Inner core of 6 laid around a straight centre wire. Around this is laid 12 more wires. There are 19 wires laid round a central core. Suitable for almost all standing rigging

7X7 7 strands each containing 7 wires is more flexible but weaker. Suitable for safety lines, control cables and trapezes.

7X19 7 strands with 19 wires each is the most flexible. Suitable for running rigging, fishing nets and steering cables

MAXIMUM BREAKING LOAD IN KILOGRAMS

DIAMETER		1 x 19		7 x 7		7 x 19
MM	INCH	AISI 304	AISI 316	AISI 304	AISI 316	AISI314	AISI 316
1.2	3/64	170	110	122	87	122	87
1.6	1/16	227	215	231	205	217	142
2.0	5/64	363	336	295	263	295	230
2.4	3/32	545	484	417	332	417	323
3.2	1/8	953	861	798	652	798	602
4.0	5/32	1497	1340	1089	1030	1089	956
4.8	3/16	2132	1930	1678	1493	1678	1373
5.5	7/32	2858	2540	2268	1950	2268	1807
6.4	1/4	3720	3440	2903	2642	2903	2450
7.2	9/32	4718	4350	3523	3353	3528	3031
8.0	5/16	5670	5380	4082	4140	4082	3820
9.5	3/8	7938	7580	5443	5830	5443	5388
11.0	7/16	10206	10200	7393	7820	7393	7230
12.7	1/2	12799	12799	10342	10900	10342	9628
14.3	9/16	14599	14599	12927	13180	12927	12206
16.0	5/8	18399	18399	15876	16500	15876	15300
18.0	45/64			20192	21000	20192	19300
19.0	3/4		21600	22498	23284	22498	21569
20.0	25/32			24928	25800	24928	23900
22.0	7/8		29070	30164	31200	30164	28900
25.4	1.0		40600			38737	38642

LIGHT PATTERNS

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INTERNATIONAL CHART ABBREVIATION

OLDER CHART ABBREVIATION

LIGHT PATTERN

CLASS OF LIGHT

Fixed continuous	F
Flashing (Light shorter than Dark)	Fl
Group Flashing ( 3 shown)	Fl(3)	Gp Fl(3)
Isophase (Light & Dark equal)	Iso	.
Single Occulting (Dark shorter than Light)	Oc	Occ
Group Occulting ( 2 shown)	Oc(2)	Gp Occ(2)
Continuous Quick	Q	Qk Fl
Group Quick ( 3 shown)	Q(3)	Qk Fl(3)
Interrupted Quick	IQ	Int Qk Fl
Continuous Very Quick	VQ	V Qk Fl
Group Very Quick ( 3 shown)	VQ(3)	V Qk Fl(3)
Morse Code ( K shown)	Mo (K)	.
Alternating (Changes colour)	ALWR	Alt WR

DIGITAL SELECTIVE CALLING (DSC)

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A VHF or HF radiotelephone with DSC fitted can send a distress alert and position reports if connected to a GPS. It can also be used for urgency, safety information dissemination or routine calling and answering. The information is sent as a burst of digital code to either rescue authorities or to an addressee. Subsequent contact is by voice. DSC acts like a paging system with the alert being both audio and visual alarms. Included in the call is the caller's Maritime Mobile Service Identity (MMSI) and what mode or channel is required for further communications. Once contact is made the conversations are public. A caller will need to know the 9-digit MMSI Number of the station being called. For more infomation see the DSC item in Safety & Survival.

DSC EMERGENCY FREQUENCIES

DSC Frequency	Associated Frequency
VHF Ch 70	VHF Ch 16
2187.5 Khz	2182Khz
4207.5 Khz	4125 Khz
6312 Khz	6215 Khz
8414.5 Khz	8291 Khz
12577 Khz	12290 Khz
16804.5 Khz	16420 Khz

DSC SERVICE (ROUTINE)

Ship Receive (Khz)	Ship Transmit (Khz)
4219.5	4208
6331	6312.5
8436.5	8415
12657	12577.5
16903	16805
22444	22374.5

DSC ALERT CONTENTS
* MMSI number of the Caller
* The Alert Priority - Menu selectable from Listing, Sinking, Disabled, Abandoning, Piracy, MOB, Fire, Flooding, Collision and Grounding.
* Last known position and time (preferably GPS)
* The station(s) being called

ABOUT OILS

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Properties
   Oil does more than just lubricate. Aside from reducing friction by lubrication oil also removes heat from moving parts, creates a better seal (between rings and cylinder), and cleans engine parts. Engine oil is divided into two broad categories - Petrol and Diesel.
   An oil for a petrol engine is designated by the letter"S" and for a diesel engine by the letter "C". Some oils can be suitable for both and can carry both the A & C rating. A second letter from "A" to "H" is used to specify quality - A being best. Petrol engines are designated SA, SB, SC, SD, SF, SG & SH. and for Diesel engines CA, CB, CC, CD, & CE. The number designator denotes the viscosity - of which there are two types Mono & Multigrade. Mono grade oils do not change viscosity with temperature. However a Multi Grade oil will get thinner with increase in temperature. Therefore a multi-grade oil will have a number designator giving a range. eg Multi-Grade SH 10-30.

Changing Oil
Changing oil at the right interval is vital to the serviceability state of an engine. Oils with additives deteriorate over time. The cleaning action leaves foreign matter in the filter which eventually becomes ineffective whereupon the cleaning action stops with consequent over wear on moving parts. Therefore engine oil needs to be changed on both a time basis and an engine hour basis. When topping up engine oil, the mixing of types or specifications should be avoided. Whenever the oil is changed so should the filter at the same time.

Marine Watch Site Map

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