Category Archives: Navigation & Communication

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Navigation & Communication

Bars, bars, bar

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Sailing down the Pacific Coast of the US. Bars, bars, bars. Is this post about drinking? No, it is about waves, jetties and shallow water when entering a bay, harbor or marina. We started going south from B.C. Canada toward Mexico at the first week of October. That is certainly the beginning of autumn with a different weather pattern. With a pro dominant Northern wind which is oké when going South. The bad thing, there are more depressions with high winds and a North East direction. The wind isn’t the bad aspect, it’s the waves rolling onto the shore that is the factor to be aware off.

So the Pacific is deep, 1000 meters and beyond and it goes back to zero in 30 NM. When entering a harbor, marina on the west coast in the state of Washington, Oregon or California it’s usual a shallow bay or cove, protected by side jetties, partly submerged. Sometimes a canal, 20-30 feet deep, dredged. The entrance is called a bar…..

So the buildup of waves, rolling in from the west, can be 12-18 feet and then also breaking and rolling. That is a scary thing to look at and definitely not something you want to be in.

Website and Coast Guard for Bars

So information is key, you can’t go and have a look and be safe at the same time. Luckily their is a site for Bar Observations (by the Portland Meteo Office). And almost every harbor has a local coast guard with info on VHF 22A. (Switch your marifon from International to US)

A lot off actual data can be retrieved from NOAA buoys. Look at the app NOAA Bouy Reports in Google or Apple store. A graphical interface makes things so much easier.

Strategy for Bars

The down site, it takes a week before clearing up, the sea needs at least 2 days to calm down. And then you need 2,5 days for your next 300 NM south and the next harbor. So if the bar is open hop on the back a southwards going depression and sneak in the next harbor before the next depression arrives. It’s all about “reading” the weather predictions.

When 40-60 NM outside the coast, waves are back to 6-9 feet (2-3 meter) with a wavelength of 12-15 seconds. And in the same direction as the 15-20 knots of wind. So for a Seawind catamaran that is more or less a “perfect” combination. We like the sound of riding down a wave, the goorgeling sound of water under the bridge deck, salon floor. When the wind dies down, waves are back to 3 feet.

Most Harbors in WA and OR are fishery harbors, we visited Port Angeles, Grays Harbor/Westport, Goos Bay/Charleston, Bodega Bay. In general enter at slack tide, high water. For instance Bodega Bay is really shallow. We spent 13 days at Westport, partly because we did a 4 days road trip to Eugene, but mostly because the bar was closed. We skipped the Columbia river, Astoria. Notoriously difficult at high winds and wicked currents.

San Fransisco Bay

More south we stopped at San Fransisco Bay, Santa Barbara and Catalina Harbor. More relaxed, better temperature. San Fransisco Bay is special because of the Golden Gate bridge crossing. We came in by night, because of the slack tide we needed and a full moon. We anchored down town. I appreciated the site of Patrick Twohy with a top recommendation for Aqautic Park.

In Santa Barbara the main thing beside relaxing and eating out, aka anything else then fish and chips, was a visit to the West Marine shop. Needed a few things including a new barber hauler line for my Jib.

Catalina Harbor is a unplanned stop because of a gail warning of the Coast Guard. So some extra time on a nice anchorage. Mexico here we come ….

Look at the Photo Gallery for more pictures.

Navigation & Communication, Safety

Kiskaduct

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It isn’t easy to sail the North Pacific. Going from Japan to Vancouver is a challenge, even to a well build Seawind1260 like our Kiskadee. We know that before doing it and experiencing it while doing it.

It’s roughly a month of sailing and you will experience both storms and very calm weather. The conditions are hard, the water temperature is 6-8⁰ Celcius, 15⁰ on daytime, 10⁰ at night. The Webasto could get the temperature up to 17⁰ but you need to run it long and hard. Consumes 0.6 liter per hour. Port tank only. About 50% of the days where foggy, flying water or raining, a few days really sunny.

No wind

Calm weather is annoying because you can’t motor-sail all of the time, doing 1400 – 1600 rpm on one engine you burn 1.4-1.6 liters an hour for 3.5 knots of boat speed. So a day of motor-sailing burns 35-40 liter, 16-17.5% of a tank. We were not able to do a stable drift on autopilot. Not enough speed for the AP to maintain a course and constantly rudder alarms. You can’t look the steering wheel by a friction nut, so a construction with elistics and rope is needed.

To munch wind

Bad weather is also annoying but for a different reason. You worry about the boat. Big winds, up to 30 knots, big waves 3 meters plus. Going on a broad reach, its very doable, long waves from behind, sometimes surfing. 90 to 120 is very oncomfortabel, a screwdriver wobble. And more into the wind, a course of 40 to 50⁰ is frightening if the wave length in between is to short. Big bangs of water to the hulls, underneath the bridge deck and to the watertank. So the main thing to do is depower, slow down your speed. Almost no Jib and put the boom outside and lose a lot of wind. Any speed over 7 knots is uncomfortable.

Experience

So up to 20 knots of wind we sail with all sails up, except when we are doing 30-45⁰ AWA and waves are short to each order. First reef then give a more stable boat going over the waves in stead of through them. We discovered that all weather models under estimate the wind strenght in the night by 3 to 4 knots. And more gusts. So the well known first reef by night and reduced job. The jib add a knot of boat speed between fully and 50% deployed, but is the first action to stop Kisadee slamming through the waves.

Breaking things

We had 2 times the furling badly shaved and replaced, shorted and the third reef line, already shaved, snapped during a storm with ~27 to 30 knots of wind. We anticipated the snapping of the third reef and had a second construction setup at the front and back at the boom. The outer hauler shaved and snapped. The parasailor tacklines and barberhaulers lines get broken mantles which we repaired.

Shaving is a major problem, all reef lines to the back off the main, especially at the batten pockets, all halyards at the lewmar clutches, all barberhaulers where they touch the sheets, furling line on the furling drum window. Three solutions, daily inspections, duct tape on lines at shaving points and no tension on lines like reefs, topline, furling line etc when not in use.

User errors like breaking a lewmar clutch when running a line directly to a winch in stead of first to a running block. Losing a stopper at the Jib rail by losing control of the furling line and no tension on the jib sheet in high winds. The block wasn’t secured, pin down, so the stopper took multiple hits and broke off. A broken and glued back stopper for the self trailing disk on the small winch on port side. A ring of the dighy snapped off, too much tension in the wrong direction with a hard polyester line. But all repairable.

Condensation

Our biggest challenge is condensation. 10⁰ difference in temperature between out and inside and a lot of most is a real challenge. Not only windows and hatches, but complet hulls, inside cupboard’s, walls everything condensates. We generate to much most, by wet clothes, cooking, breathing. Airing is not a solution, we would like to stay a bit warm inside. So microfil clothes and wringing on an 2-hourly base. And everything is damp.

We long for a sunny and calm day to open hatches and and let warm and dry air into the boat.

Other stuff

We had our starboard engine running hot twice. The problem was an air leak at the gross filter between the housing and the top, hold together by a wing nut. A little petrol jelly and a hand tightening did the job. We learn the first time to look at the filter before looking at the impeller Wich was fine.

We had multiple errors on Vesper Cortex, Iridium Go and B&G MFD, NAC3 aka the autopilot. Running them constantly longer then 1 to 1,5 weeks generates software problems. The solution is simple, ones a week reboot all appliances. Do some hand steering.

(first published 21 June, limited internet)

Navigation & Communication, Prep, parts & Maintenance, Safety

Crossing the North Pacific

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After a delivery from the Seawind factory in Ho Chi Minh city and via stops at Philippines, Taiwan and Japan, we are now prepared to do a crossing, big circle navigation from mid Japan to Vancouver in Canada.

Straight line it’s an ~ 5000 NM trip, big circle 4200. We think it will be a max of 5000 NM including tacking, avoiding a depression etc. With an average of 132 NM a day it will be a maximum of 37 days crossing without any landfall.

Crossing Choshi - Vancouver
Crossing from Mid Japan to Vancouver

Preparation

The preparation is not much different then any, except you need to think harder about food supply, fresh, frozen etc. The freezer and fridge are full with fresh produce, yogurt, cheese etc. We were very pleased with frozen vegetables in addition to fresh. Fresh water is never an issue thanks to the water maker and the big tank on Kiskadee. Our Solar panels keep filling up our batteries to 100% even on a rainy day.

The usual stocking of diesel (light oil in Japan), we added 4 jerrycans of 20 liters. We calculate the amount of hours you can run your engine. With a 1600 rpm on one engine we use 1,6 liters an hour, and do about 3,5 knots of boat speed. Our Webasto heater uses 0.6 liter an hour. So there isn’t enough diesel to do long mothering, 2 * 125 hours or 875 NM. That is 17,5% of the distance. It is called a sailing vessel. 🙂

Weather Forecast

The first step is to look at the historical data when to cross. Luckily all that hard work is done by Jimmy Cornell with Pilot Charts and his well know book World Cruising Routes.

So crossing toward Japan is preferably done in March and April, latest in May, because the Typhoon season starts. And this year, perhaps of the really hot weather, they are early and powerful. The crossing of the North Pacific, Japan – Canada / US, is always a sailing trip between lows and highs with either a lot or no wind. Depressions are getting in from the Russian mainland, coming from (North) West going North East. The other path are the remainders of Typhoons, storms coming from the middle Pacific, going to Philippines or Taiwan and then up North East to Japan, Mid Japan. They tent to go East (or North East). The water around the Kuril and Aleutian Islands is still to cold to feed these systems.

The passage from Mid / North Japan – Middle Aleutian Islands is a nice one because their is a strong global current pushing you in the right direction. It is an alley between the most depressions and it avoids the big summer high pressure area between Midway / Hawaii and the east coast of the US. Its a great circle navigation and shorter than a direct straight line.

Doing it

We had an option to leave Choshi, Mid Japan to have a favorable wind direction for almost a week. Combined with the strong Kushiro current. The down side, within 7 days the leftover of the Typhoon Mawar, a deep storm depression was going to pass us at 400 NM.

6 knots of current
6 knots of current

So on day five the storm took a path more North than the previous forecast. We adjusted our course to straight north, getting closer to Hokkaido and put an extra 100 NM between us and the outside of this depression. Winds at one time up to 30 knots, but current, waves and wind in the same direction. Big waves 3-4 meter but with more than a boat length between them, not uncomfortable. Its was a night with tension, the passing of the center and the turning and lowering of the wind took a long time.

Current we are motor-sailing with 6 knots of wind and the forecast is that will be the case for the next 2 days. Progress is good, we past the first 1200 NM.

Fun, Navigation & Communication, Prep, parts & Maintenance

It giet oan

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A famous frysian saying to indicate the 210 kilometers skating match on natural ice, “It is going on”. So we did. Finally our SV Kiskadee, a Seawind1260, was launched and we were part of the factory sail to commission her in Nha Trang.

Ho Chi Ming City – Nha Trang

A three day, 2 night sail from the Saigon Delta to the Northern city of Nha Trang. First serious sea trail for SV Kiskadee and part of the commission protocol from the factory. Skipper mr. Phil Harper and Mr. T, both from the factory and our self as crew.

A beautiful and difficult sail because of an overwhelming number of fishing vessels. The first full day, bumpy with 20 knots of wind. Reefed against the current. We alternated a two man watch, 3 hours up, 3 hours down. The second part was with less and less wind, motor sailing for at least a whole day. Arriving at night at 20 hours.

Commissioning in Nha Trang

We needed a complete 4 day hand over. Checking six pages of items. For most of the items out of our chairs into a compartment, bildge or behind the coach. Fixing things like getting all coms and navigation integrated, on the professional accounts. Checking software versions, all latest, 🙂 Putting the parasailor up for the first time, we had the turn the boat.

A few repairs, installing a new B&G Trition, adjust the first block on the main sheet. Instructions on Spectra watermaker, heater, washing machine etc. And the first oil change on the Yanmar engines and Saildrive.

And doing motor maneuvering for Therese, I listen carefully and got a lot of tips to. On Tuesday we had a handover and now we are the owner, in charge and responsible .

Kiskadee profile

Nha Trang – Sub Bay Philippines

With our crew, Jon, Will, Therésè and Eddie we departed on our first journey, a 900 NM partly upwind course to Subic Bay in the Philippines. We prepared as much as possible, combined our experiences with a new yacht, in a new area, with a lot of fishing boats and big fast running cargo ships. Not scary but some time indeed excited.

Half way our journey we enabled our track and trace page based on our Iridium Go.

Navigation & Communication

SAS.Planet explained

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Ok, I looked into SAS.Planet as a standalone tool for offline satellite images as an aid to navigate sparsely populated areas with errors in mainstream navigation charts. What is SAS.Planet, is it legal because it contains a lot of chart content, is it safe to use because its a Russian product, is it tracking me via back doors or extra code?

How does it technically works?

SAS.Planet is a program designed for viewing and downloading high-resolution satellite imagery and conventional maps submitted by internet services as Google Maps, DigitalGlobe, OpenStreetMap, Bings Maps (Bird’s Eye), ESRI and Navionics. But in contrast to these services all downloaded images will remain on your computer and you will be able to view them, even without connecting to the internet.”

After selecting a satellite source SAS.Planet fetches from the internet the view and stores it locally as a gis file. Even a detailed sonar map of Navionics is a call the chart server. SAS.Planet emulates too be an app using an application programmable interface.

Storing it locally as a gis file, called Cache, is nothing strange. And the parameter Internet & Cache is anything a disconnected sailor wants.

Security

Yes, its maintained by a group of Russians, the primary language of the website is Russian and also the default language of the Program. But with Google translate on the site and English as the language in the app, its a useful tool.

The program is written in (Borland) Delphi a slightly older but common programmers language. I checked all internet/server requests while using it and in my opinion, version 201212, is doing exactly what its made for, fetching maps from general internet sources. For example: http://mts1.google.com/vt/lyrs=y@176103410&x={x}&y={y}&z={z}&s=Galileo&scale=1&hl=en

SAS.Planet is 100% file based, the executable, ini-files, preferences and maps are all in a directory. So it didn’t need to write to the Windows registry. It works well on a W10 operating system.

SAS.Planet, a powerful tool for offline satellite images

Using it

In general there are to ways of using is, as a stand-alone tool to study an area or an approach. If you buy a stand-alone USB GPS receiver SAS.Planet will turn into a navigation aid.

A second way is to study an area or approach, save the images and export them in an mbtiles or other format, as explained in this youtube video.

There is a ton of functionality, most not needed for a sailor wanted only to use satellite images. I made a custom version with only satellite maps activated. <link>

march 2022

Navigation & Communication

C-Map vs Navionics charts

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My new B&G Zeus3 accepts both C-Map and Navionics charts, which one to choose? The top of the line, C-map Max-N+ (now REVEAL) or Navionics Platinum+, offers a lot of features of little interest to me. Pseudo 3D, relief images of the bottom, too colorful. (march 2022: C-Map renamed its product Max-N+ –> REVEAL

There is also a price argument. Navionics is more expensive, there is a price increase of 50% between Navionics+ and Platinum+ and a smaller covered area. For Navionics+ the coverage of “large” is UK + Ireland + Netherlands (€ 243 in 2020). You need 2 Platinum+ cards (UK + Ireland and NL for 2 * € 365), which is an increase of 300%. The subscription costs 50% of the purchase price annually.

C-Map is more affordable, the largest covered area is called Continental Charts or Extra Large. For example Northern Europe for € 233 and the Pacific side from Panama to Canada € 179. There product is renamed form Max-N to DISCOVER. The subscription costs 50% of the purchase price annually.

C-map is therefore the winner of this competition, but you have to look at your sailing area. For us: Vietnam to Japan, the crossing to Canada, hoping to Panama, Micronesia towards NZ and Australia, an unusual route that crosses both densely populated and sparsely populated areas.

Navionics+ Pacific Charts
Navionics+ Pacific Charts
C-Map Pacific Charts
C-Map Continental Pacific Charts

And then it is clear that island hopping from the very south of Japan to Central Japan is not covers by a C-map Continental chart. Look for the Wide (Costal) equivalent or if absent buy a Navionics map. The same goes for Micronesia towards NZ.

Accuracy

Navionics and C-map provides maps for South Pacific toward NZ, but it is well known that they are not very accurate. Looking for alternatives there is one valid option, Satellite Charts or Overlays. If you are the owner of a Navico plotter, like B&G, then you can integrate them on your device, otherwise you an alternative like OpenCPN or Ovital or .., I still look to sailors forums for input on converted maps of that area. So there are a few ground rules for navigating ‘uncharted’ waters.

  • Always search for information before creating a route;
  • Zoom in or activate the correct number of detail layers on your chart plotter;
  • If possible, activate an alarm depth of ~ 5 to 10 meters, quickly respond with an opposite heading when sounding;
  • Put way-points 5 NM away from your destination, obstacle, reef barrier;
  • Never approach at night, go slow (I broke this rule a few times);
  • Use satellite imagery to aid in your navigation at that particular entrance.

OpenCPN with satellite images

New features on the top version of C-Map and Navionics are Aerial Photos. But not available in C-map Max-N + Continental charts and for Navionics Platinum + only in relation to SonarCharts, the community database. Guess what, you have to be online and the coverage of sparsely populated or economically uninteresting areas is low.

So satellite overlays is it. Satellite overlays can be done in a number of ways. It all started with:

  • Paul Higgins who wrote GE2KAP (Google Earth to KAP, Chart Image Files) started the Satellite Overlays movement. Known, works with old version of GE, Windows oriented, see http://gdayii.ca/index.php . Currently known as SAT2Chart.
  • SAS.Planet, a Windows standalone program to download images from different providers, also see my article on how to integrate SAS.Planet images on the B&G Zeus3.
  • Venture Farther, is a plug-in on top of OpenCPN, works with a database in which images are stored. A great feature from the same programmers is a tool for uploading your NMEA depth data from your course as a favor to other users. For more information Vfkaps Charts on OpenCPN or their own website at https://www.venturefarther.com/.

I will do some research on SAS.Planet, especially using its offline. To be continued …

Edited, march 2022

Navigation & Communication, Story in Dutch

Windverwachting Kaag

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Hoe hard waait het? Hoe lang, draait de wind? Wat is de windverwachting? Ik vind het beantwoorden van deze vragen zeer verschillend voor een paar uur zeilen op de Kagerplassen of voor een oversteek naar Engeland.

Voor een avondje zeilen op de Kagerplassen is de wens van de windverwachting “hoeveel wind staat er, richting en neemt deze af of toe”. Die vraag is goed te beantwoorden met een “normale” weer app. Ik gebruik Weather XL Pro als android app. Geeft per uur een indicatie, voldoende wind-info (knots, richting etc) en regen-info (kans en hoeveelheid). Makkelijk in gebruik, gratis en niet te opdringerig met advertenties, eenmalig € 4,95 advertentie vrij. Er zijn vele alternatieven.

Standaard gebruik ik ook Rainy Days (Rain Radar) van Hugo Visser voor de overtrekkende regenbuien. Opnieuw makkelijk in gebruik, kijkt een uurtje vooruit, goed in en uit te zoomen.

Meer, gedetailleerde informatie over de wind

Als de windverwachting een stevige 4 bft. is, wil ik meer informatie zien. Eigenlijk heb ik dan 3 aanvullende vragen:

  1. Ik wil per uur een voorspelling in knopen wind omdat het verschil tussen een kleine (11 knopen) en forse 4 beaufort (16 knopen) uitmaakt voor een centaur, polyvalk
  2. Hoe nauwkeurig is de voorspelling
  3. Hoe hard ‘vlaagt’ de wind?

Er zijn vele, vele wind apps, de trend is dat ze meer en meer een abonnementen structuur hebben en een lite versie die voor mij niet werkt voor bovenstaande vragen. Ik licht mijn keuzes toe waarom ik kies voor Windfinder PRO (opnieuw eenmalig € 4,95 voor superforcast per uur).

Modellen voor de windverwachting

Je wilt dat de windverwachting gebaseerd is op een lokaal model met een kleine grid. Voor Nederlandse vaarwateren zijn dit Harmonie (2,5km), Arome (1,3km) en ICON-EU (3,5-7 km). Het globale model GFS maar ook ECMWF zijn niet goed genoeg. Zij houden geen rekening met de lokale topografie (eiland, meer, landtong etc.) Hoe instabieler het weer, hoe meer de globale modellen afwijken. Harmonie is helaas niet standaard voor apps, Arome en ICON-EU steeds meer wel.

Windverwachting via Windfinder Pro - Superforecast
Windverwachting via Windfinder Pro – Superforecast met lokaal weermodel

Er is verschil tussen lokale modellen. Vaak het tijdstip dat een verandering, bijvoorbeeld een overtrekkend front, bij de Kaag is. En dat is belangrijk als je zeilt op de rand van de maximaal toegestane wind. Of moet beslissen wel of niet iets af te gelasten. Het tijdstip doet er dan werkelijk toe.

Werkelijke wind

Weerstations in Windfinder
Groene Dots zijn weerstations.
Derde tab is de actueel gemeten windsnelheid

Alle modellen zijn maar berekeningen. De werkelijke wind doet er toe. Dus is de laatste vergelijking; wat is de werkelijke wind van dat moment. En dat is meteen mijn laatste en beste tip. Je kunt dat gewoon opzoeken in Windfinder ipv allerlei webpagina’s.

Voorschoten is een KNMI weerstation, dichtbij, zeer betrouwbaar, altijd in werking. Simpelweg selecteer Voorschoten als favoriet en vergelijk de werkelijke wind in de derde tab met de gedetailleerde voorspelling van de Kaag.

Het tweede verschil is de voorspelling van de kracht van de vlagen, gust. Globale modellen zijn daarin erg pessimistisch, lokale zijn iets beter. In de praktijk is Arome daar beter in dan Harmonie. Maar hier is de ervaring (kijken naar de wolken) en Rainy Days en de metingen in Voorschoten net zo belangrijk.

Van cijfers naar een beslissing

Weather XL PRO als algemene indicator, meestal voldoende. Alleen bij veel wind of een weersomslag kijk ik naar Windfinder Pro Superforecast. Kijk dan ook nog een paar uur naar de werkelijke wind (Voorschoten) in Windfinder Pro.

Oké maar wat beslis je dan? Wat is je interpretatie? Hoe lees je het?

Voorbeeld eerste plaatje Kaag

De wind neemt toe (helaas is mijn foto te kort, vanaf 20:00 uur neemt de wind snel af), er zijn harde vlagen en de regen indicatie gaat van 0 naar 2,9 naar 0,5 mm. De wind draait niet. Er komt een bui over, met harde vlagen. Het is geen front want dan draait ook de windrichting. Ik zou uitvaren met een rif gestoken en een bemanning die niet bang is. Ik zou de Spriet (Lede) naar Leiden zeilen. De vernauwing bij de Kaagsociëteit en bij Hoogerboom is van Zuid naar Noord en dat is opkruizen in iets nauwer vaarwater.

Voorbeeld tweede plaatje Voorschoten

(andere datum, los van plaatje 1) Ik zie dus in mijn superforcast Kaag de wind toenemen, uur na uur met een break vanaf 17:00. Ik kijk die dag meerdere malen op de werkelijke wind bij Voorschoten en zie elk uur de grafiek veranderen. Om 16:00 uur zie ik dat het afgelopen uur de lijn horizontaal geworden is. Als dat in lijn is met de voorspelling Kaag is het weer omgeslagen. Dit is een ideale zeilmiddag of avond, niet gereefd, de reguliere wind gaat van 12 naar 5 knopen.

Voor diegene die nog een stapje dieper willen gaan. De windrichting draait, kijk toch ook even naar de regenverwachting. Er is een front overgekomen, actief betekent misschien ook regen. Is het hoogzomer en valt de temperatuur met een graad of 5? Ook even kijken naar onweersystemen.

Algemeen

Bij een stevige wind, vooral bij de pieken, is de vraag: Een uurtje eerder of later beginnen of eindigen? Oftewel kom binnen voor je overvallen wordt. Centaur, één rif of Polyvalk 2 riffen? Vinden we het nog leuk? Regen- en onweersbuien? Wie zeilt er mee? Hoe wild is het op de plas i.r.m. met de jachthaven? Of drinken we nog een bak koffie en gaan we weer naar huis! Het reglement van mijn zeilvereniging zegt niet uitvaren bij 17 knopen reguliere wind.

Voor tochtplanning en voorbereiding gelden andere regels en gebruik ik ook andere tools, zie ook Tochtplanning.

Navigation & Communication, Story in Dutch

Planning, Route & Wind

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Voor een tocht Yerseke – Lowestoft – Enkhuizen – Yerseke, 23 – 31 augustus 2021, doe ik de planning en voorbereiding. Normaal zijn dat al een heleboel stappen , maar nu komen daar de covid maatregelen bij. En dan blijkt meteen dat ons plan niet uitvoerbaar is. We mogen Engeland wel in, we zijn allemaal volledig gevaccineerd maar terug in Nederland moet je een PCR coronatest van maximaal 72 uur oud laten zien en dan nog eens 10 dagen in quarantine. En dat past niet in ons schema.

Dus een alternatief plan, naar het Noorden want de stop in Enkhuizen is essentieel voor het Lustrum van de Zeezeilvereniging Genosea.

De aanpak

De globale route planning is niet direkt een ingewikkeld proces. Ik doe altijd zo iets van:

  • het doel: “flink zeilen”, nachttocht, getijden, rivier c.q. Wad;
  • de club: ideaal met zijn zessen, allemaal zeilers, we zijn wel eens goed zeeziek;
  • waar gaan we naar toe, hoeveel zeemijl, grofweg, altijd een ambitieus plan en een kortere versie;
  • wat is historisch de heersende windrichting, gedurende die week op die route, fijn dat Windfinder.com gewoon statistieken heeft;
  • alternatieven bij teveel wind, andere tegenvallers

De bestemming

De ambitieuse bestemming is Helgoland, Duitsland, de twee eilanden zo’n 50 zeemijl boven Delfzijl. Dat is zonder overnachten te halen in krap 3 dagen met een zw of wzw wind zeker als het 3 a 4 beaufort waait.

Ik gebruik de website van Navionics om een initiële route te plannen. Ik stel de draft van de boot op 3 meter in, dan vermijd de automatische route berekening de ondiepten.

Route planning
De automatisch uitgerekende route

Windverwachting

Je kunt op twee manieren naar de windverwachting kijken. Als je planning ver in de toekomst ligt dan kijk je naar de historische waarden en vanaf een dag of 10 naar de concrete voorspelling.

WindHistorie Borkum
Historische winddata in WindFinder