Route planning - how to estimate speed

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trswem
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Route planning - how to estimate speed

Post by trswem »

Howdy folks. I'm excitedly planning some trips for this summer where we'll need to cover some miles. How do you folks estimate speed made good when route planning? I have days where I'm clipping along nicely at 6.5 knots and then I have days where I never see the SOG go above 2kts, that's sailing! I have a 80 mile trip, and no idea what to plan for in terms of how many miles I can do a day. I've been using 4knts as an average speed, thinking I'll motor along if I really get in a tough spot. I'd really rather sail SLOW than motor slow, so I'm giving myself a full three days of buffer time so I don't get stressed about not covering enough ground. But I'm curious how you folks go about planning pace.

Thanks!
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Russ
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Re: Route planning - how to estimate speed

Post by Russ »

I think if you are not going to supplement speed with the motor, you have to be flexible. Allow for your destinations to vary depending on distance.

This is unless you are planning certain stops that you need to meet each day. Then I guess you average it out and then fire up the iron genny if speed isn't working for you.
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Tsatzsue
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Re: Route planning - how to estimate speed

Post by Tsatzsue »

trswem wrote: Thu Mar 28, 2024 10:13 am Howdy folks. I'm excitedly planning some trips for this summer where we'll need to cover some miles. How do you folks estimate speed made good when route planning? I have days where I'm clipping along nicely at 6.5 knots and then I have days where I never see the SOG go above 2kts, that's sailing! I have a 80 mile trip, and no idea what to plan for in terms of how many miles I can do a day. I've been using 4knts as an average speed, thinking I'll motor along if I really get in a tough spot. I'd really rather sail SLOW than motor slow, so I'm giving myself a full three days of buffer time so I don't get stressed about not covering enough ground. But I'm curious how you folks go about planning pace.

Thanks!
I typically use 4.5 Knots / hr as my planning speed when creating routes. That was always a good mid line for my V25. I am now in a 26M so that can vary but I still use that.
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rsvpasap
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Re: Route planning - how to estimate speed

Post by rsvpasap »

I see you're located in Spokane. Coeur d'Alene is 25 miles long, so I assume you're talking about sailing Puget Sound and the San Juans. If so, the tide can make all the difference. Here are a couple of screenshots for Admiralty Inlet and Rosario Bay today. Very generally speaking, the tide changes direction every six hours and, at least south of Port Townsend, the wind is usually blowing pretty much directly north or directly south because of the mountains.

Sailing with or sailing against a 1-3.5 knt tidal current are vastly different experiences in a 26-ft boat, especially one with only a sliver of keel. In one direction, you can easily be zipping along under sail at 5+ knots with 5-10 knots of wind. Meanwhile, going the other direction, you will probably need the outboard to make substantial progress. You're just not going to sail against the wind and tide up the channels of Puget Sound at any real speed. On the other hand, with the wind and tide in your favor, you can readily approach hull speed.

I previously sailed the Great Lakes, with no real tides and a much more predictable sea state, so planning was relatively simple assuming there was no possibility of storms. On the other hand, in the PNW, in my opinion, there really can be no rule of thumb. It's highly variable depending on the tide, the speed and direction of the wind, the sails you deploy, your skill and experience, your willingness to be persistently tuned into changing conditions for many hours at a time and your willingness to motorsail. Actually, this is what makes it fun and interesting, it's radically different from day to day.

Study the tide charts, get the best wind predictions you can, make sure you time your departure to coincide with the conditions you need in order to make a favorable passage. There have been many days I have hauled anchor before dawn because of expected conditions. On the other hand, I would advise against sailing this area at night, especially following a very high tide or substantial rains, due to the amount of debris in water.

In my experience, the paid version of the Windy (red) app that shows the forecast in one hour increments, set to the HHHR model, is the most reliable predictor of the wind for the next 36 hours. Beyond 36 hours, the European model ECMWF and the general NOAA forecast are probably most helpful. Suggest you study the various wind models in order to gain a better understanding of how they apply to your circumstances, including weather underground, which is the only major service that incorporates real-time data from private weather stations. Best of luck.

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trswem
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Re: Route planning - how to estimate speed

Post by trswem »

rsvpasap wrote: Thu Mar 28, 2024 11:33 am I see you're located in Spokane. Coeur d'Alene is 25 miles long, so I assume you're talking about sailing Puget Sound and the San Juans.

In my experience, the paid version of the Windy (red) app that shows the forecast in one hour increments, set to the HHHR model, is the most reliable predictor of the wind for the next 36 hours. Beyond 36 hours, the European model ECMWF and the general NOAA forecast are probably most helpful. Suggest you study the various wind models in order to gain a better understanding of how they apply to your circumstances, including weather underground, which is the only major service that incorporates real-time data from private weather stations. Best of luck.

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We're not braving the tides yet! We'll be on Lake Pend Oreille, Coeur d'Alenes big brother to the north.

I've been using Predict Wind and wondered about the paid version of Windy, I think i'll give it a shot. Thank you!
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rsvpasap
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Re: Route planning - how to estimate speed

Post by rsvpasap »

That's a beautiful area. I would say 3.5 knts (4 mph) for sailing, 6 knts (7 mph) for motoring. I hope you have a great time.
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Re: Route planning - how to estimate speed

Post by NiceAft »

When you say 80 miles; is that the total trip, or an 80 mile leg?

I have done a 200 mile trip with 50 mile legs, and used the motor instead of wind. I don’t want to spend 8 hours in the boat when I can get to where I want to be (5 hours), and then relax when I get there. I can do that in my :macm: On short legs, I do 5.2 ~ 6 knots.

In June we will be doing another 200 mile (round trip) cruise of the Chesapeake. Depending on what the situation is in Baltimore, will determine if Inner Harbor is one of our stops.
Ray ~~_/)~~
trswem
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Re: Route planning - how to estimate speed

Post by trswem »

NiceAft wrote: Thu Mar 28, 2024 3:00 pm When you say 80 miles; is that the total trip, or an 80 mile leg?
80 miles round trip, and we will likely break that up into about four days. Because of the shape of the lake, and out loose agenda, we'll also have the opportunity to cut off 20 miles if the kids poop out or if there's just no wind. This will be a leisurely trip.
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Be Free
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Re: Route planning - how to estimate speed

Post by Be Free »

For a rough estimate I usually use 3.5 knots as my average speed under sail. That is also my "sweet spot" for running the engine for my best MPG. Those are my numbers for my pretty heavily loaded "X" with a 40hp 4-stroke.
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Re: Route planning - how to estimate speed

Post by DaveC426913 »

NiceAft wrote: Thu Mar 28, 2024 3:00 pm I don’t want to spend 8 hours in the boat when I can get to where I want to be (5 hours), and then relax when I get there.
I confess, this is me.
8 hours may not seem so much in a big cruiser with lots of room, but in a bathtub the size of a Mac, I can get squirrelly after five hours or so. It becomes a much less relaxing experience as I start calculating if I'm on track for my timeline or if I'm falling behind, and wondering if I'll be missing the dinner bell or trying to dock in twilight, etc.
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Re: Route planning - how to estimate speed

Post by DaveC426913 »

trswem wrote: Thu Mar 28, 2024 3:41 pm 80 miles round trip, and we will likely break that up into about four days.
Ah. That sounds pretty doable.
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Re: Route planning - how to estimate speed

Post by Gotro »

I have done the Texas 200 twice now and this club plans its anchorage at 30 to 40 mile apart. And over 6 days it’s very doable and not overbearing on the sailers.
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Be Free
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Re: Route planning - how to estimate speed

Post by Be Free »

40 miles a day is very doable. I've done it many times under sail and under power (twice under a small craft advisory). One trip was 7 days with another person. We got off the boat once for about an hour to get some ice. Another was 5 days solo, never touched land.

Another thing to keep in mind for long trips is to have alternate stopping points along the way. We have sail boats so it's good to plan your stops based on your sailing speed. Because we all know the wind does not always cooperate you should also identify places where you can stop short if the weather turns bad or your'e behind schedule.

Sometimes there is just no good stopping point along the way and you have to push through to the next anchorage. That's when you motor sail or just motor. If you have a chart plotter that shows your current ETA as well as your preferred route you will always know what time you're going to arrive based on your current speed and position. Eventually the plotter may tell you that you just can't get to a safe anchorage under sail alone. Time to hoist the iron genny.

Even if you plan to sail the whole way, that does not mean that it's going to be possible. It's also a good idea to calculate how much time and fuel will be needed to run under power at your planned speed the entire way (the worst case). Now, if you calculate that you're going to need 12 gallons to make the whole trip at your planned speed then carry 18 gallons. That way you can use 1/3 of your expected fuel down, 1/3 back, and still have 1/3 in reserve. Remember those two days under small craft advisory? That was the only time I actually got into my reserve and I was very glad to have it. Even so, I still had 2 gallons in the tank when I pulled up to the dock.

Hope for the best. Plan for the worst. Stay safe and have fun.
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Re: Route planning - how to estimate speed

Post by NiceAft »

Gotro wrote: Sat Mar 30, 2024 5:26 am I have done the Texas 200 twice now and this club plans its anchorage at 30 to 40 mile apart. And over 6 days it’s very doable and not overbearing on the sailers.
Speed is the big determiner of comfort. How long does it take to do 40 miles. 10 MPH = 4 hours; that’s very doable, but if one goes at hull speed, the time then is 6.33 hours. That is a significant difference.
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Be Free
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Re: Route planning - how to estimate speed

Post by Be Free »

NiceAft wrote: Sat Mar 30, 2024 10:48 am Speed is the big determiner of comfort. How long does it take to do 40 miles. 10 MPH = 4 hours; that’s very doable, but if one goes at hull speed, the time then is 6.33 hours. That is a significant difference.
I agree. A leisurely 10 or 12 hours sailing is much more comfortable and relaxing than four hours under power. :wink:
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