| Author | Message | ||
     David Sheriff Board Administrator Username: Admin Post Number: 48 Registered: 01-2004 |
Not to denigrate the value of a well-calibrated magnetic compass, but in these GPS days it's not nearly as important. Using your GPS, get on your desired course. Note the compass reading. Steer to that (corrected) compass heading. Its tough to steer by the GPS directly because it does not update fast enough. You end up chasing the goal from where you were, not where you are. Even autopilots steering under the direction of a GPS use a magnetic compass (or equivalent) to determine what to do in the short-term. Two caveats: we are assuming your GPS is set for magnetic degrees, if that's what you're using. Duh. You need to repeat the GPS/magnetic process for any substantial heading change where you need to steer a specific course expressed numerically. Compass variation is not uniform on all headings. But if the skipper just says "head up five degrees," just do it. It doesn't matter that the compass may not read the actual heading of the boat. It matters that you know what compass heading to steer. | ||
| Ted Lavino Senior Member Username: Tlavino Post Number: 385 Registered: 01-2004 |
1. Escape's radio did not support dual channel scanning and since visibility was greater I didn't feel the need to waste batteries on a handheld monitoring VTS. 2. I think Marie would disagree with your assertion that a plot was not kept. Agreed she did not plot as often as she should have, but I made sure she did an electronic fix and DR plot at least once every 2-3 hours. 3. Escape did not have a deviation card. The combination of lack of vessel access and the Saddleback schedule precluded swinging the ship to generate one ourselves, so we agreed not to worry about deviation on that particular trip. That's not to say one should not do so as a general rule, just that we made the concious decison not to do so due to external factors. | ||
| Marc Hughston Moderator Username: Hughston Post Number: 432 Registered: 03-2003 |
Ted, you never even attempted to listen in on VTS last trip, never checked on compass deviation, and did not maintain a DR plot. Why bother making this an SOP if you're not going to do it? | ||
| Ted Lavino Senior Member Username: Tlavino Post Number: 380 Registered: 01-2004 |
Greetings folks, as you may recall from our organizational meeting Susie has agreed to take on the on the water Navigator role with assistance from Jerri to take some some of the load off of me. However, Jerri and I will be doing the voyage planning and pre-cruise navigational duties. As such here are my Navigation SOP's (see my previous posts for information a navigator should be prepared to provide). I will post them in the log binder for reference on-board. We will be using American labelling conventions for labeling items on charts such as bearings, fixes and DR plots. For this trip we will be using the trip log rather than the cumulative log. The deck watch is responsible for entering the cumulative log reading in the deck log each morning as part of their daily precruise checklist (in case the trip log is reset by mistake during the day. For multi-day passages the cumulative log is normally used). The depth sounder (if equipped) is to be configured to use the same depth units as the chart currently being used for navigation. The deck watch shall is responsible for changing units on the depth sounder at the appropriate time. We will be piloting via visual navigation until we exit Dana Point harbor and come upon bouy #1. at which point the on-duty deck watch will take a fix and commence a formal DR plot. DR plots on this voyage are to be done every ½ hour and whenever a change in course or speed is ordered. Fixes are to be taken when feasible, but at a minimum of every hour on the hour using both viusal (if available) and electronic aids. Courses and bearings are to be plotted in degrees magnetic. The helm will be responsible for correcting for any compass deviation. The deck watch will be responsible for maintaining the DR plot and any associated log entries in accordance with posted SOP's under the Navigator's supervision. The deck watch will also be responsible for maintaining the Weather Log in accordance with posted SOP's under the Navigator's supervision. The deck watch will be responsible for entering Vessel Traffic Service-related communications into the VTS log and bringing the oncoming watch up to speed regarding any traffic headed our way. | ||
| Ted Lavino Senior Member Username: Tlavino Post Number: 370 Registered: 01-2004 |
Greetings Navigator(s), as mentioned in the general SOP I'd like you to post your own Navigation SOP to this area to provide the crew with direction and information relating to navigation procedures you would like to see followed. Since the crew may be acting under your supervision (something you need to decide and communicate to the crew, but is strongly suggested) as they update the deck logs during their watches. You should provide information as you see fit, but be prepared to justify your decisions to the captain/skipper. I would suggest that you be thinking of the following issues: 1. Which chart labeling conventions are to be used (European or American)? 2. Will there be a single navigator or will you delegate responsibilities to the deck watch? 3. Ditto for VTS monitoring responsibilities? 4. Which depth unit should the fathometer be configured to use, and when should it be changed? 5. Where should formal navigation be started vs. piloting? 7. Should we use the trip log or cumulative log? 8. Should we chart courses and bearings in true or magnetic? 9. Should we log courses and bearings in true, magnetic or compass? 10. How often should we update the DR plot? 11. How often are fixes to be taken? You should provide and be able to justify your own answers: |
