2012-08-23: Routing for the return trip, including WAYPOINT ROUTINGBased on GRIB data from August 22th, for a departure on 23rd, 0800HST. I'll present the usual routing, but this time enhanced with an additional routing forced to waypoints, which you may have selected for your return. At the end I'll repeat my wave warning for the California coast and also alert you to take a good look at your diesel supply! Finally I present an attmept for alternative waypoints, which might mitigate some of the problems I see. Remind yourself that the router is for racing, hence it routes for sailing-only! It does not take into account the potential of motoring, which obvioulsy you are free to do in a return or delivery sail. Further, as you can see from the quite different graphs for two seemingly rather similar boats, the routes will look different for faster boats, like Maggie, not to mention even faster ones. (I'd be happy to implement any boat's polars if you can provide them to me, see Note on top of this page!) However, I believe general features can be extracted nevertheless. With that caveat there is not much to add to my analysis from three days ago (2012-08-20). You should still go basically due north initially, then turn on a wide bow, which brings you rather far north, towards San Francisco. What it means for one specific set of waypoints is analyzed below the following routine routing graphs. |
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Return routing for a Cal40
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Return routing for a Pacific Seacraft 44
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Routing with Waypoints: Cirrugator allows you to enter waypoints for your trip, and it will go from waypoint to waypoints, strictly along a rhumbline from one to the next, analyzing the conditions along the path that you have determined by defining the waypoints. So, it actually does not do a routing itself! But then it derives your expected performance from the conditions it has found. For the set of waypoints 30N/155W, 35N/150W, and 38N/140W the outcome is shown in the next graphs. Consistent among the two boats, for at least 2/3rd of distance, the bottom graphs find the blue, round dots (=app. wind angle) in the whiteish area in the middle, which is the no-go zone for a sailboat. In other words you would have to tack to sail the course. But since the wind is also down to way down for almost the same segment, sailing is slow to very slow. More likely you would be motoring for 2/3rd of your trip. Make sure you have a matching diesel supply!!! |
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Return WAYPOINT routing for a Cal40
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Return WAYPOINT routing for a Pacific Seacraft 44
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Wave Warning: For a few days already, and forecasted to last for at least the next 10 days, the wind along the California coast is strong and steady from NNW. Therfore the likelyhood increases that big waves will build, moving SSE. Cirrus had encountered such a situation in 2010, and the crew didn't like - to use a euphemism :-| . You definitely want these waves to not hit you from beam, but rather more from behind, like 150-160 degrees (on port). You achieve this by being in a position sufficiently north, so when you start pointing to San Francisco, the waves will hit you where is hurts the least. A last waypoint like 38N/140W may not be north enough. Please, consider! |
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GRIB wind profile
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GRIB wind profile
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Alternative Waypoints: Using the Cirrugator waypoint routing feature, I played around searching for better alternatives. Unsurprisingly, nothing really perfect popped up. However, some advantage might be achieved for waypoints 38N 157W, 40N 150W, 42N 135W, as shown in the next graphs. Again, consistent among the two boats, the return can be divided into 3 parts of roughly equal length. The first third is a mix of decent sailing in decent wind speed and wind angle, and poor wind with porr angle, probably necessitating motoring (wind 14-6 kn). The second third is mostly very low wind. Oddly, studying the grib wind pattern, I can't even make out whether this is a high or not. This is really 5-6 days of motoring. The last third has good wind, allowing good sailing. The pleasure might be limited by the waves. However, as soon as it becomes clear that there really will be strong northerly waves, one could even go a little bit further north before pointing to Overall still a good chance for a decent return. |
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More Return WAYPOINT routing for a Cal40
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More Return WAYP. routing for a Pacific Seacraft 44
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2012-08-20: Routing for the return trip, departing Tuesday, 21thBased on GRIB data from the 19th. Excellent conditions for the race - which is almost always synonym for poor conditions for the return. The default of "go north, turn right", is again largely justified. Again, click on the graphs and study the bottom graph 'Route Analysis' to convince yourself about my interpretation. There is too much of long term clause hauling for a return. And the initial good and even strong wind is lost soon. But the second half of the return - if conditions prevail and you have positioned yourself carefully - may turn out to become a real higlight with beam reach conditions all along. However, it might go along with high waves! I think that starting on HI one would want to go almost due north (10deg true at the most) to enjoy beam reach for as long as possible. Then it looks like motoring for a while, before you could even continue under spinnacker. Go very high to a point like 40N/140W (give or take a degree) to put yourself in a good position at your halfway point. Might need some more motoring, but eventually puts you into beam reach territory for the remainder of the trip. Stay alert for possible northerly winds along the California coast prevailing for a long time. It could result is high waves from the north, as Cirrus had experienced in 2010. You better try to catch the waves as far from behind as possible, further underlining the desire to go really north first! Might overall still be a rather fast return! |
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Return routing for a Cal40
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Return routing for a Pacific Seacraft 44
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2012-08-11: Routing for the return trip, departing Sunday, 12th - Oh, Dear!Based on GRIB data from the 10th. It looks truly awful. If you were planning on sailing-only, it would be a close-hauled-crawling for almost the whole trip. More likely you will be motoring for a loooong stretch! Make sure to stack up on diesel fuel. To really appreciate the awfulness, do click on each of the graphs below, and in the bottom graph 'Route Analyis vs Longitude' study the apparent wind angle along the route. Also look at boat speed (it is low) and the wind speed. Wind is also low for almost 3/4 of the trip, and only turns to the better during the last quarter (remember that the last quarter is the most uncertain part of the forecast!). Close hauling for a long part of the return is still out of the question, so what remains is going north from HI under sail until the wind dies down, then motor for almost half of the trip to get near 35N/135W and hope that you can sail from this point onwards. It will be a noisy return :-( |
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Return routing for a Cal40
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Return routing for a Pacific Seacraft 44
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2012-08-04: UPDATE - Routing for the return tripAn update for departure on August 5, from Hawaii to San Francisco. All what I had said on August 1 is still applicable. The issues are even more pronounced Click on each of the graphs below, and in the bottom graph study the apparent wind angle along the route. While the Cal 40 is basically tacking her way home - yuck - the Seacraft is taking a long detour, but is sailing rather comfortable at decent wind angles; slow regions will be handled by motoring. Don't even think of sailing close hauled for any length of time! It will be a crew's nightmare come true! Use the old rule: "go north, turn right!". |
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Return routing for a Cal40
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Return routing for a Pacific Seacraft 44
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2012-08-01: Routing for the return tripPer request of a friend on a C&C 37 I did some routing for a return trip from Hawaii to San Francisco. There are some caveats to observe - in fact, it does take some chuzpe to make a forecast like that. Here are the issues:
However, even with all these caveats, some features emerge. And since those features are consistent with experiences from the past, conclusions drawn from them seem to be (somewhat) justified.
As a conclusion for now, I'd say follow the old rule: 'Go due north until you reach the latitude of San Francisco, then turn right' ;-) Looks more like 3 weeks for the return. Good news is, that wind may be sufficient for most of the time for a speed equal to what you would do under engine, so not much need to run the engine, and therfore a quiet boat! Aaaaah! |
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Return routing for a Cal40
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Return routing for a Pacific Seacraft 44
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2012-07-25: unchanged situation -- just go straightI did the routing, but it is just too broing to present. They need to just point to the finish line, and do their best. VALIS has a chance for arriving before midnight from 29th to 30th Hawaiian time, Nozomi shortly after midnight.
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Tracks of Div A
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Tracks of Div DH1
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2012-07-24: Halfway done. Horserace to finish lineNo surprised from the weather to be expected. Now it all depends on making the best judgment of when to jibe in order for pointing directly to the finish line. Some have jibed already; that may have been a bit too early.
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Routing for Nozomi
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Routing for Valis
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Tracks of the whole fleet
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Tracks of Div DH1 + A
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2012-07-23: Routing is still boring. All goes in good wind as promised.The whole fleet is moving "north" (to be more precise: they move further north of the direct line to Hawaii; their course is almost due west), the only reasonable thing to do. Wind is good, and for many it is becoming a horse race.
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Routing for Nozomi
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Routing for Valis
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2012-07-22: Routing gets boring. They do what they need to do. Now.When you look at the wind pattern of today, and compare this with the one just before the race (at the bottom of this site) you will notice that is has not changed by much, if at all. (Remember that the red arrows are wind FORECASTS along the route of the boat, and NOT the wind at any specific point in time!) Therefore all the routing from before the race is still valid. So it is still valid that those early starters should have taken a more northerly approach than they did. But since they stayed more rhumbline-ish, there is no benefit from venturing too much into arctic regions now. Looking at the tracks from both boats since the last reported position, they are going very slightly north, and this is pretty much what they should be doing now. And not much change seen for the remainder of the race, just sail fast ;-)
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Routing for Nozomi
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Routing for Valis
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Tracks of the whole fleet
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Median North position of each division
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Tracks of each division @ 22.7.2012 2300PDT
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2012-07-21: Not much different from yesterdayGoing northerly is still the best option, but no by much - so it would not stress either boat too much ;-). Keep in mind that when you do stay on the rhumbine permanently, staying on it for the remainder of the course will always become the only option at a certain point! Valis benefitted from poor perfromance of Cassiopeia and went up the ranking one notch.
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Routing for Nozomi
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Routing for Valis
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2012-07-20: The race already decided among the first starters?It looks like the decision for the route may have been taken by both boats, Nozomi and VALIS, a few days ago already, and it was a course of rhumbline or even south of it. It seems to have been a sub-optimal choice; the more northerly boats are gaining on them. The later starters started off on rhumbline or well below, which in their case makes sense given the change in wind pattern.
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Routing for Nozomi
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Routing for Valis
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Tracks of all First-Day-Starters
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Tracks of the whole fleet
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2012-07-19-Part B: How are the early starters doing?
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UPDATE: Routing for Nozomi
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UPDATE: Routing for Valis
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Routing for Nozomi
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Routing for Valis
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2012-07-19-Part A: departing to the south and then wiggling around the rhumb line?
Again, this is not a continuation of the routes of boats that have already started, but it looks at routes the two considered boats should take, if they were starting today at 1445PDT.
Both boats are slow boats, at least when compared against today's starters, therefore conclusions derived from the slow boat routes and applied to the fast boats need to be done with caution. (I don't have the fast boat polars - if you can provide any, I will use them!). However, the overall wind pattern looks so smooth and consistent all over the route, I guess it will be a safe bet this time. Even more so since they will also be faster, so they might have arrived before the weather even thinks about changing ,-)
But their polars might suggest a benefit from an initial deeper wind angle, so I think they might be going a little bit south, and then wiggle around the start-to-finish rhumb line. That's my guess.
The routing for Cal40 (Green Buffalo)
Almost same as yesterday, except now a full day faster since the initial sluggishness is mostly gone. I also caluclated six additional alternate routes. You can see them as the multiple colors routes near Hawaii. This broom-like widening is only mathematical noise - there are really no meaningful alternative routes to the red route! It would also mean a single jibe for the whole race ... (see blue circles in Route Analysis graph)
The routing for Pacific Seacraft 44 (Valis)
Also no significant changes to a Valis-like boat, except that today's start would be a full day faster than yesterday's!
2012-07-18: better starting, then a fast, still northerly race
This is not a continuation of the routes of boats that have already started, but it looks at routes the two considered boats should take, if they were starting today (in about 5 hours after this writing).
The best routes for the two boats - a Cal40 and a Pacific Seacraft 44 (Valis) - now differ a bit more than previously, though do still share similar features. Starting may now be best in a southerly direction, but heading back to beyond and much beyond the initial Great Circle is suggested (iniital Great Circle is thin yellow line in the graphs). It would have been an even faster race for them, were they starting today (but they are not and wasted time in the initial poor conditions).
I used today's GRIB file and sneak peaked into the starting conditions of tomorrow: it gets even better. In general, the course for both boats would be closer to Great Circle, i.e. shortening the distance to sail, and hence shortening the finish time. Once again the late starters have the better conditions!
The routing for Cal40 (Green Buffalo)
Twelve and a half day on a course 100 miles longer than GC is surely nothing to complain about!
The routing for Pacific Seacraft 44 (Valis)
Apart from the first few days a steady 14-20 knots of north to north-easterly wind would have allowed an excellent 12.1 days!
2012-07-17: same as yesterday - from slow to speedy on northerly route
This is a route for a Cal40, if she had started on Tuesday at 13:30h, using the latest GRIB file from before this start.
Note that this route is NOT a continuation from yesterday's first starters, but rather like a fresh start today!
Not much difference from yesterday, except that the route is now hugging Cirrus' PCup2010 actual route even more closely (see post at the bottom of this site).
A bit of comfort comes from the route now forecasting a bit less time spend at very deep sailing angles, making the race a bit more manageable, although it would take some chuzpe to trust the weather in that detail that far ahead.
The routing for Cal40 (Green Buffalo)
Routed finish time of 13.42 days is a tiny bit faster than yesterday, so far reaffirming expectation of an overall fast race despite a slow start.
2012-07-16: initial crawl will turn to fast race on very northerly route!
This is what the routing forecast looked before the race had started. The GRIB file's 1st valid date was 2h before the first start.
The calculated routes for both boats - polars taken from Green Buffalo, a Cal40, and Valis, a Pacific Seacraft 44 - suggest a slow crawl from start which might take 2 days, and then a northerly route - more north than Great Circle - with decent wind and limited needs for jibing ;-). The "classical" southerly route is definitively not recommended. This looks very similar to the PCup 2010, as can be seen in the post at the bottom of this site.
A problem might arise from sailing for too long at a very deep angle, as can be seen from the Route Analysis graphs: when the apparent windangle (round, blue dots) are in the blue-shaded top or bottom ends of the graph, sailing over long periods of time, possibly with high waves, can be challenging. To mitigate, both boats might choose a route, which gets even closer to the Cirrus PCup2010 route.
The routing for Cal40 (Green Buffalo)
Assuming Green Buffalo's polars are representative for all Cal40, then Nozomi (Div DH1), the sole Cal40 in the race, should finish in 13.61 days, despite the route being 115 miles longer than Great Circle. That would be a very fast race for her despite a slow start, as her rating of 617 means an expected race time of 14.8 days! Real world sailing, enhanced by the double-handed handicap, will dampen the speed, but there are still chances for a fast race.
The routing for Pacific Seacraft 44 (Valis)
Valis' rating of 614 means an expected race of 14.7 days, while this routing suggests zipping along for only 13.16 days! Route would be 59 miles longer than GC. Here as well, real world sailing will dampen the speed, but chances are there for a fast race.
Pacific Cup 2010 - Northerly routes are not unusual
Two years ago, the early starting slow boat Cirrus (Div B) and the late starting fast boat Mirage (Div E) were on very similar routes, and both were very northerly! And several other routes were very similar.
Cirrus' route is in red. This route maybe shown in the routing graphs above as the red line with filled red circles as markers.
