Tactical Compass Overview Clay Babcock Mar 8 th, 2018 3/9/18 1 Overview WYC Philosophy Compass Background Types of Compasses The Art of Going Upwind Well Other Device Functions Tactical Compasses Reviewed Mounting, Tips, etc Class Rules VHF etc etc 3/9/18 2 1
WYC Philosophy Racing, sharing, going fast, having fun SHARE YOUR FAST 3/9/18 3 Compass Background One of mankind s most important inventions A device that always points to magnetic north pole Uses natural or man-made magnets 3/9/18 4 2
Compass Card Rotates to show North (and all others) Four Cardinal directions N E S W 360 degrees, 90 between each cardinal Needs to be viewed from a fixed point 3/9/18 5 True vs Magnetic North Compasses point to the Magnetic Pole Located North of Canada Creates a difference between True and Mag North Declination WYC is lucky! 3/9/18 6 3
True vs Magnetic North 3/9/18 7 Marine Navigation Navigation: going to a place you cannot see And (key!) getting BACK The original and primary marine use Most bulkhead mounted compass for this purpose 3/9/18 8 4
Types of Compasses Compass technology has changed in the last 20 yrs Machine readable Smaller smarter faster This has improved sailing! 3/9/18 9 Magnetic card The only kind of compass for 900+ years Simple, mechanical, reliable HUMAN readable 3/9/18 10 5
Fluxgate Electronic devices cannot read a card Converts the turning card to a signal Must be kept reasonably level 3/9/18 11 GPS Based GPS does NOT know heading! It calculates course via 2+ location fixes Moving from 1 to 2 must involve a known course MUST be moving! 3/9/18 12 6
Heading vs Course True compasses show HEADING Where the bow is pointing GPS compasses show COURSE 3/9/18 13 Micro Sensor (MEMS) A revolution in compass and sensor tech Extreme miniaturization of these components Grain of rice sized First in phones, now in marine devices 3/9/18 14 7
The Art of Going Upwind We don t navigate on Lake Minnetonka Why does a compass help us? Whiteboard time! 3/9/18 15 Wind shifts mean big changes A boat that is : knocked is sailing wider angle to the mark lifted is sailing tighter angle to the mark Boat speed to the mark (VMG) is effected The effect cannot be ignored 3/9/18 16 8
VMG Velocity Made Good Component of your Boat Speed that is in the direction of your destination When fetching: VMG=BS When going to windward: VMG=BS*cosine(TWA) 3/9/18 17 Calculations At 5 kts BS 45 degrees to windward: 3.54 kts VMG 55 degrees to windward: 2.87 kts VMG 35 degrees to windward: 4.10 kts VMG On a 1nm windward leg Disregarding lifts/knocks = 3.5 kts VMG Staying lifted = 3.91 kts VMG At the windward mark: 107 seconds 30 boat lengths 3/9/18 18 9
Finding Mean Wind Must be able to hold windward course Take readings on practice upwind Mean, Median, Mode to get average Tack and note Tacking Angle Do the same on other board Validate with what the RC is saying Use their number in a pinch Your angles are then +/- your Tacking Angle 3/9/18 19 Remember this is a TACTIC As part of an upwind strategy Other factors can and will apply Sometimes pressure is more important When would you not tack even when knocked? Better pressure ahead Less traffic ahead Want to get back to the middle Can t! due to traffic 3/9/18 20 10
Polar Speed Diagrams Plots Boat Speed vs True Wind (speed & angle) Each boat is different! Gives angles for optimal VMG Upwind Downwind 3/9/18 21 Other Device Functions Lift-knock indicators Race Timer Backlight Boat Speed Some of these can effect class legality! 3/9/18 22 11
Tactical Compasses Reviewed Described more or less in chronological order Will list functions and cost Describe first hand experiences Welcome other first hand input! 3/9/18 23 KVH Sailcomp Original tactical compass Fluxgate based Three part, wired system $1000 3/9/18 24 12
Raymarine Tacktick RaceMaster Fluxgate based, dual display Solar powered Lift indicators, race timer $750 3/9/18 25 Raymarine Tacktick Micro Fluxgate based, dual display Solar powered Tactical display $350 3/9/18 26 13
Velocitek ProStart GPS-based, battery powered Split display, also shows speed Race Timer, Distance to Line $600 3/9/18 27 Velocitek Shift 9-axis sensor based, solar power Race timer, lift indicator Backlit display $700 3/9/18 28 14
Nautilytics Alloy 9-axis sensor based, solar powered. $335 3/9/18 29 Nautilytics Simple Compass 9-axis sensor based, solar powered Start timer, backlit $375 regular on sale $335 3/9/18 30 15
Velocitek Prism 3-axis sensor based, solar powered just a compass $399 3/9/18 31 Racegeek D10 9-axis sensor based + GPS MANY functions Wireless + NMEA $1000-$1400 3/9/18 32 16
RSTO app 9-axis sensor based App version of ProStart $3.99 3/9/18 33 North Sails Tactician App Enter wind angles on upwinds Graphs and notes highs and lows $FREE 3/9/18 34 17
Tacking Master Wrist based Tracks shifts Shows key angles & bearings $75 3/9/18 35 Mounting, Tips, Etc Fixed, 90 degrees to centerline Mast mount allows for all crew to see If boom lines, check for clearance Bulkhead gets knocked, obstructed Keep it on the boat! 3/9/18 36 18
Class Rules Check with your Fleet Captain to be sure Fleets can dis-allow: All Electronics GPS Stored values or computations Navigation functions (DTL) Any non-magnetic sensor 3/9/18 37 VHF Radio VHF radio has been the standard for short-range marine communications since 1947 Analog, walkie-talkie technology While advances made, backward compatibility key While smaller, cheaper and more channels, VHF radios were basically the same until 2000 3/9/18 38 19
DSC and MMSI DSC Digital Selective Calling A digital way to call a particular device Many types of calls, including 911 MAYDAY Needed a marine phone number MMSI Maritime Mobile Service Identity Assigned to a VHF radio (FCC or BoatUS) A database entry with boat information Name, type, length, color, port, owner, picture, etc LOCATION, DESINATION, SPEED, COURSE 3/9/18 39 DSC Distress Single button solution to MAYDAY Digital signal has better range than analog Mostly foolproof, less stress errors Reports all MMSI info, plus LOCATION 3/9/18 40 20
DSC - AIS Automatic Identification System Machine-read MMSI packets sent on intervals Over VHF or Internet Allows: Plotter overlays Direct VHF calling Collision Alarms 3/9/18 41 DEMO 3/9/18 42 21
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