Last Minute before an Ocean Passage
10/05/15 11:47 Filed in: Offshore sailing
By Paul Shard, Copyright 2015. All rights reserved.
It's amazing how many little things are on the list when you are getting ready to do a big ocean crossing. The passage across the Atlantic - Caribbean to Azores - is over 2200 miles. It’s going to take us more than 13 days, perhaps 15 or 16, more than 2 weeks out of sight of land. We don’t want any important items left on the to-do list when we cast off in a few days. I still have a few small rigging jobs to do (lazy jack line replacement, taping up spreader ends etc) I need to look over the engine again, I have to clean the propeller and finish cleaning the bottom and a number more items…
The modern sailboat is a complicated machine with thousands of parts and they should all be working well before setting off to sea. But making a big crossing where there are no possible stops it is even more important. Is everything in good shape now? Do we have the proper spares if anything goes wrong? This week there have been the sobering reports of a number of boats lost at sea en route to the Azores in heavy weather. It brings into sharp focus the reality of setting out on an ocean passage. It is a serious business crossing an ocean. We want to be prepared as well as we can and make a safe crossing.
One of my jobs here in the last few days is to get familiar with the new Iridium GO unit and PredictWind software we are testing on this passage. The unit arrived yesterday and I will get it configured and practice with it over the next few days. I am especially interested in trying the PredictWind feature to help plan your departure date. Using a polar diagram (chosen from a list of common boats) to approximate our performance, the software calculates routes and times for the passage over 4 different departure dates. See the slide below… This shows recommended routes for the next four days. Note we are at the very outer realms of forecasting ability asking the software to calculate 2 weeks in advance and in fact the later departure routes do not quite complete since the forecast doesn’t cover the 18 days needed to calculate however en route we will be getting daily weather updates via the PredictWind app and the GO unit. This is just for planning and when we are at sea we will be using the routing tools to fine-tune our course. Initial impressions are that this will be a valuable tool.
There is also a table generated showing how much of your time is spent in different conditions, for example “% time reaching” ranges between 62% and 93% depending on which weather model and departure date is chosen.
|Start Time||10 May 12:00||10 May 12:00||11 May 12:00||11 May 12:00||12 May 12:00||12 May 12:00||13 May 12:00||13 May 12:00|
|Passage Time (days)||13.7||13.2||12.9||12.9||12.0||11.8||10.9||10.9|
|Max wind speed (knots)||18.6||19.5||22.5||18.6||23.6||16.2||20.8||15.9|
|Min wind speed (knots)||2.4||3.2||1.7||1.7||3.8||2.0||3.4||1.5|
|Ave wind speed (knots)||11.0||12.4||13.7||10.6||14.6||10.7||12.0||10.3|
|% time upwind||22%||2%||25%||5%||35%||8%||43%|
|% time reaching||74%||71%||72%||83%||62%||88%||54%||93%|
|% time downwind||4%||27%||3%||12%||3%||4%||4%||7%|
|% time < 8 knots||29%||16%||7%||27%||5%||20%||17%||15%|
|% time 8 - 20 knots||71%||84%||85%||73%||79%||80%||81%||85%|
|% time 20 - 30 knots||7%||16%||3%|
|% time 30 - 40 knots|
|% time > 40 knots|
|% time < 1m swell||25%||47%||28%||45%||22%||49%||23%||51%|
|% time 1 - 2m swell||75%||53%||72%||55%||78%||51%||77%||49%|
|% time 2 - 3m swell|
|% time 3 - 4m swell|
We are also hoping to get the Iridium GO unit to produce a tracking map of our route in real time! I will get this installed on our homepage so you can follow along if you like. Hopefully we will have all our jobs done by Wednesday and will be setting off shortly after that.
Of course the best way to follow along on our voyages is by watching the Distant Shores Television series! Not in real time but we document our journeys and share destination hints and tips. The whole series is now available for download on Vimeo. See you out there!
Order the Super Pack on DVD and get Season 1-10 Downloadable.
Order the Super Pack on Vimeo and we will send you the code for Season 10 as a bonus.