Passage Planning

[Troutbridge]

Originally Posted by ssullivan

I have "World Cruising Routes", but at this very second it's still in storage while I await delivery of my new boat.

From what I reacall, it shows you routes, but doesn't say exactly how long a given route is, plus what if your route isn't specified in the book?

Also, I never had an atlas on a boat, due to self-imposed weight restrictions (we have a fairly small "library" on the boat). However, having an atlas sounds like a pretty good idea. There is likely a scale somewhere on the map that you can use your dividers with for a fairly accurate rough estimate.


Lastly, using a GPS doesn't work at all. Say you were going from Greece to Brazil. Plug those both into a GPS and you're off by hundreds if not thousands of miles. There are plenty of sites that allow you to do "as the crow flies" distances, but they do not account for the fact that you can't sail over land.

Er, don't quite follow you there sport. Create a series of waypoints that correspond to the route you want to follow and that will give you a Great Circle distance. Agreed that you can't sail over the land so when selecting where to put a waypoint, stick with the blue bits.

[Peregrinata]

Another good piece of software in offshore route planning is "Virtual Passage Planner". It will give you Rhumb Line or GC route distances between selected positions, optimal route tracking based on pilot chart data and you can input your boat info and it will give you the time on each leg. The pilot info does not take into account weather anomalies but it is a good start.

[GordMay]

Visual Passage Planner 2
Digital Wave - Home
VPP2 - Downloadable Edition $119.00
VPP2 - Boxed Edition $129.00

[SV Someday Came]

Been working on the boat all weekend, and I missed the responses!

I'll order Cornell's book, check those .gov and software sites. Using the multiplier is a very nice rule of thunmb. You are right, if can afford Interlux, I can afford that resource. What I meant by the difficulty of getting my arms around time and distance is that when I have to drive someplace, by a glance at a map, after all these years of driving, I have an intuitive sense of roughly how much time a trip would take. I have no such intuitive sense (YET!) when it comes to ocean distances more than from LA to Catalina Island.

Michael

[SV Someday Came]

Looks like a revised edition is forthcoming in Mar08. I'll hold off till this new edition is available. Looks like a tome: 640pp!

[Pelagic]

Admiralty "Ocean Passages of the World" is a reference I have used for years. Expensive though!

Admiralty Ocean Passages for the World - 5th Ed.

[Troutbridge]

You will develop that sense once you know the boat better. I read somewhere that most yachts average approximately 100 nm per day. That seems a bit low to me, thinking about the Atlantic Trades where I planned on 150nm per day, and mostly achieved more than that.

[the5]

Not exactly sure why, but the World Cruising Routes, 5th edition is half the price of the 4th
Amazon Online Reader : World Cruising Routes

[imagine2frolic]

What ever the cost you will want the book, or books. By simulating your waypoints along the intended routes you will get distance, not as the crow flies. In the trades you will most likely average hull speed minus a small percentage. I don't know if the 20, or so % is what you would use, but those who have done the trade winds know already know best.

A pair of dividers, and some routing charts will also you give you some numbers to work with. This may cost you a total of $50, or less........BEST WISHES

[Sonosailor]

Try the ruler on GoogleEarth. I just scanned the answers here, and maybe I missed somebody else suggesting this. I've used it for my passages from Canada to the Carribean, and the numbers come out ok. Remember that the site provides statute miles and you will have to convert to nautical miles. It might be more accurate if you break the larger passages into intermediate points. Try it both ways.

[btrayfors]

Two useful steps in passage planning are to:

1. find the rhumb line distance between points you wish to visit; and

2. estimate the time required to cover that distance.

You can find the rhumb line distance between any two points on earth by entering the departure latitude and longitude, and the arrival latitude and longitude. You can find the lat/lon of most anywhere simply by Googling it.

Once you have the lat/lon, here's an online calculator to figure out the distance and direction: JavaScript Navigator - Mercator Sailing

Most small cruising boats average between 100 and 150 nautical miles every 24 hours. Some do a bit better, some worse.

What speed you will make over a given course depends very much on winds and currents, as well as other factors such as boat speed, crew, etc.

Bill

[SV Someday Came]

You know, this is very useful to me and I suspect to others as well. Do you folks here ever distill a thread and post like a "sticky" about the topic?

[Kanani]

I've done 2 complete circumnavigations and more boat deliveries than I care to count. When passage planning I plan on 100 NM per day. Pure and simple. You will seldom be dissappointed.

The only reason that you would want to know how long a trip is, is for provisioning. If you are trying to determine the length of time that your entire journey will take....all I can say is....DON'T. Setting time perameters on a cruising schedule is one of the most dangerous things that you can do. My suggestion is to plan 100NM per day and double the length of time for food and water. Each passage inclusive, of course. Any left-overs are included into the next passage supplies.

The only thing worse than wasting $ on unused provisions is not having enough in the event of an emergency (dismasting....dead engine.....lost rudder or steering....no wind....etc). There are no home deliveries at sea.

Another good rule for fuel provisioning is to never run your engine unless you have enough fuel to motor to the next safe harbor (non-stop). For the same reasons as food provisioning, above. This will become very relevent if/when you make the Marqueses passage.

[barreldriven]

The most simple answer would be to take a coastal navigation class to learn the math involved. Reasonable price through US coast guard Aux.

[Eleven]

I find distance for the routes I've planned in ten minutes with sector legs and all that stuff.
I use the Microsoft flight simulator which allows route planning. The maps are fairly good with coastlines drawn well enough for planning. There is the added bonus of flying the route at fast time (x16) on auto pilot at a couple of hundred feet which gives a good idea of the shape of things to come, ht of coast and hills.
Just wish they'd put sail boats on it so I could get some practice.
Are there any sailing sims that will help me understand?