Guest Posted January 24, 2011 Share Posted January 24, 2011 Does any one ever use these on a yacht? We never have needed to use one what are the benefits? Any one got one they can post so I can figure out what it is and make one? I understand they are different to each boat but I have done a little bit of sailing and never seen one in use or even talked about them except for inspections. Link to post Share on other sites
Deep Purple 511 Posted January 24, 2011 Share Posted January 24, 2011 Ha, I have one in my plane too. Just get a good quality hand held compass. Place it well away from everything metal. Do a few 90 degree turns and record the difference between it and your main steering compass on a slip of waterproof card. In theory you are meant to line up on a known directional reference, i.e. your marina berth, both ways and/or maybe the xyz pier walkway both ways. Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 Yep Skins you need one and it will be specific to your boat. The best part of getting one is you get your compass tuned up in the process, given the construction of your boat it likley that you will have a 0 deviation card which may seem a bit rediculous but at least you can know exactly where you are heading. trust thy compass bro it the one piece of equipment that never lies!! Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 Just a table, headings on one side, next to each heading the amount by which your compass varies from what it should read. Under about 3 degrees all round (not unusual) then you will probably never look at it again. In the good old days you would plot a number of prominent marks and their bearings from compass dolphin, then spend an hour or so motoring past the dolphin to each landmark while noting your compass heading, then draw up the card. These days I cheat, go to where you KNOW there is no current and check your compass against the GPS. If you really want to dazzle the crew you can check your compass even out of sight of land by using the pelorus and tables. Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 trust thy compass bro it the one piece of equipment that never lies!!But they can be made too. They reckon one of the biggest changes to compass accuracy in NZ waters happened when Stieny changed from steel cans to alloy ones :) Steel will feck with your compass where alloy is unlikely too by the way. You could ring Dave the legend compass dude. He can do it all for you and tweak things if you have any big errors. The authorities aren't usually too impressed with deviations of over 5 degrees. Do what the lads mention above 1st and then if you have wild numbers ring Dave. Link to post Share on other sites
SloopJohnB 323 Posted January 24, 2011 Share Posted January 24, 2011 In the good old days you would plot a number of prominent marks and their bearings from compass dolphin, then spend an hour or so motoring past the dolphin to each landmark while noting your compass heading, then draw up the card. All the ancient mariners could be seen motoring of Compass Dolphin making deviation charts also checking the logs between the beacons in Judges Bay and Okahu Bay. Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 In both directions. Link to post Share on other sites
rigger 47 Posted January 24, 2011 Share Posted January 24, 2011 If you are going to make a deviation card make sure you have the correct variation for your area when converting from True to Magnetic otherwise you may end up with an error that may not be there. Hope that does not confuse anyone.... might need to re-word it if it does. Link to post Share on other sites
smithy09 50 Posted January 24, 2011 Share Posted January 24, 2011 Dunno if I've told this story before, but I "missed" France (Crossing from Gosport, England) due to an empty can of baked beans hanging in a rubbish bag behind the bulkhead compass. Ended up in the Channel Islands... Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 Ha - I missed North Cape - Stereo speaker in the quarter berth. Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 All the ancient mariners could be seen motoring of Compass Dolphin making deviation charts also checking the logs between the beacons in Judges Bay and Okahu Bay. Still can be seen as that spot has some bloody good transits you can use. Missed France from England??? You can see the bloody thing so that's quite a miss :) Link to post Share on other sites
smithy09 50 Posted January 24, 2011 Share Posted January 24, 2011 Ha - I missed North Cape - Stereo speaker in the quarter berth. Glad I'm not the only one then! Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 meet Patrick, probably a very nice guy and some loving mothers son, Patrick does have an ability to totally f*ck your deviation card right out the window..... and he'd probably "leak"while eating soup and, sculling pints Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 Ha - I missed North Cape - Stereo speaker in the quarter berth. I don't know anyone who hasn't had the occasional cock up, if you are lucky you survive and it is called experience. Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 Great thread skins...bet you didn't think you''d kicked this little knees up off!! Yep I one of those ancients off compass Dolphin and in the old days outside HMB marina using Rangi, Nthhead, one tree hill etc, it didn't seem that hard and it was always done on a beautiful day. For all you GPS and plotter worshippers, remember Shockwave and talk to the guy who lost his launch on the reef off Rabbit Island on the Coromandel this year over the holidays, and read one of the threads here re the RNI delivery that lost their plotter. If I was off Palliser in 35kts driving southerly, horozontal rain at 2.00am and zero vis give me a compass every time, last year we were hooning into the reef at Fiji with gene and 25kts of breeze when the plotter failed to restart since turning off at Nth Cape...that compass was a beautiful thing!! It even better if it properly tuned and you know what, if any, deviation you gotta account for I know you guys know this stuff but I see so many people out on the water today who only use their plotters to navigate,some launches don't even have a compass, on a really shitty night close to land I would rank the nav tools in this order 1) Compass 2) Radar 3) Plotter Link to post Share on other sites
SloopJohnB 323 Posted January 24, 2011 Share Posted January 24, 2011 Ha - I missed North Cape - Stereo speaker in the quarter berth. Dunno if I've told this story before, but I "missed" France (Crossing from Gosport, England) due to an empty can of baked beans hanging in a rubbish bag behind the bulkhead compass. Ended up in the Channel Islands... Still can be seen as that spot has some bloody good transits you can use. Missed France from England??? You can see the bloody thing so that's quite a miss :) Is this confession time I was taking a boat to Sydney for a S2H race, hung a leftie when we ran out of land on the port side, set a compass course of 254 deg. Somehow I ended up on the gravy watch, I came up on deck and saw these darks lumps on staboard and port sides, instant action, all the crew on deck, motor started, kite down 180 deg turn. I didn't know which gap we where heading the northern between Great and Princess or Princess and west islands. The southern gaps has some bloody big rocks at the western end. At sun raise I did the compass check it was bang on. I have never worked out what took use to far north about 30 degrees about course. Having a kite up a bit of leeway, northernly current up the west coast, or just helmsmen that can't hold course. BTW it was a dark blue 50fter. Link to post Share on other sites
Guest Posted January 24, 2011 Share Posted January 24, 2011 I would have put a brain at #1, then the rest. Link to post Share on other sites
smithy09 50 Posted January 25, 2011 Share Posted January 25, 2011 All the ancient mariners could be seen motoring of Compass Dolphin making deviation charts also checking the logs between the beacons in Judges Bay and Okahu Bay. Still can be seen as that spot has some bloody good transits you can use. Missed France from England??? You can see the bloody thing so that's quite a miss :) Not from Gosport to Cherbourg, even on a good day. Lucky if you've got 5 miles vis most days.. We had about 2 miles vis.. Had to ask a fishing boat where we were... Link to post Share on other sites
Guest Posted January 25, 2011 Share Posted January 25, 2011 Forgot the chart once so rang a mate and gave him my position off the handheld GPS. Couldn't see land. He rang me back with a bearing to where I wanted to go. Just about to put the phone down before we realised he'd given me a true course. Never forgot the chart again. Link to post Share on other sites
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