Average cruising speed?

[Cincy020]

So I recently started tracking all my sails via the Navionics app on my iPhone. I'm just in a lake so I have no fancy equipment that I need. my big question is, what is a good "average" speed when cruising? I'm about three knots average and it seems a little slow. For my purposes, I am at the following: 5-8 mph winds, 150 Genoa, usually three adults and 2 dogs on board (probably about 500 lbs total), and not excessively loaded with other "stuff". Usually bring a cooler for the day and a bag with towels, etc. in it. Have the slide out galley, one type 27 battery, and 5 hp motor off the back. Bottom is relatively clean( painted this spring), but keel probably needs to be cleaned up.

Thoughts on if 3 knots is about right?

 

[Joe]

Do not get married to that average speed feature. You should determine if it includes data when the boat isn't moving. I recommend getting a dedicated handheld marine gps.... you can set "trip" data and many other items that can help you. You can also see it in daylight. This is important because it allows you to monitor boat speed as it happens.... much more important when trimming sails. The Navionics app will be limited in these features.

 

[RussC]

Sounds about right to me. ~1/2 average wind speed. [shrug]

 

[Gene Neill]

Yeah, you're in the ballpark.

I generally won't bother launching my boat if the forecast is for less than 10 mph, because if they're off by half (happens as often as not) now you're crawling along in 5 mph winds, making 2.5 knots, sweating and bored. Might as well toss the anchor, crack some beers and go swimming.

 

[RussC]

crawling along in 5 mph winds, making 2.5 knots, sweating and bored. Might as well toss the anchor, crack some beers and go swimming.

Good idea. We're packing up beer and swimsuits as I speak, headed for two days of forecasted 6-8 mph. I'm sure it will suck. (forecasters are almost always incorrect.
g)

 

[dbk0630]

I too enjoy using the Navionics app... but for me the biggest challenge is remembering to stop the track after I've returned to the marina. The first time I used it my average speed was over 6.9mph... with a max speed of 70.9 mph! So the avg speed recorded included the actual sailing part from Sutton's Bay to Elk Rapids, MI under flukey weak winds, taking the mast down in Elk Rapids, and then driving from there to Holland, MI... where I realized I needed to hit the stop button on the app! Unfortunately, I don't see a way to edit the track to show just the actual sailing part... in which I suspect we prolly averaged 1.5mph at best... so if someone knows a way to do that... don't hesitate to let me know!

 

[Cincy020]

I have found that the Navionics app has its quirks, Ike forgetting to turn it off! For $10, I thought it was a pretty good deal. Good to get some comfort I'm on that right range for speed however.

In regards to the keel, does fairing the keel have any significant effect on speed or ability to point? Is it worth it to go through the process of redoing it?

Joe, do you have any advice for a cheaper handheld GPS? Christmas is right around the corner and seems like a good idea.....

 

[Barnacle_Bob]

Cincy: I hope you don't mind my chiming in re: nice handheld GPS. I've been using a BadElf GPS receiver for a few years now, both for sailing and hiking. It was inexpensive, very compact (fits in the palm of your hand), has great battery life, easily finds and locks on to satellites, has its own display to show speed and heading, is quite rugged, and easily maps out my travels to Google or other maps - I always send guests a map showing the GPS track for the day, and they love it. It works with a ton of apps to function as a chart plotter on iOS and Android devices - I've recently used iSailGPS. I've attached a standard map of our recent family sail on Mission Bay (north of San Diego). I highly recommend it. You can attach multiple Bluetooth devices to it while sailing using their app, so everyone can see the speed, etc., on their own phone.

As for the saved speed information, I take that with a grain of salt. It picks up instantaneous spikes that I don't believe are accurate - I rely more on what I can directly observe real-time on the BadElf display than from the speed data saved to the file. For example, after racing on Lake Pleasant this weekend, the file said we hit 6.5-kts; but we were watching our speed on the BadElf display pretty intently, and the highest speed we observed was 5.7-kts... More in line with reality and hull speed.

I love mine - it was a great purchase.

- Bob

 

[Stu Jackson]

I've attached a standard map of our recent family sail on Mission Bay (north of San Diego).

Bob,

How does this function with nav charts? Your screenshot showed a Google earth satellite view.

 

[Daveinet]

In regards to the keel, does fairing the keel have any significant effect on speed or ability to point? Is it worth it to go through the process of redoing it?

Yes, but only if your keel is in bad shape. My swing keel was cast iron, so it rusted. Not bad enough to flake, but very pitted. I sandblasted it an painted it. I found it made a very noticeable difference. while drag is an issue, what is probably more important is that if the surface is poor, the water will not stick to it, and it will stall. At that point the boat slips sideways.

BTY: You asked about a GPS. I use a Sony POV camera that has a built in GPS. It allow you to overlay your speed on top of the video.

 

[Joe]

....................................
Joe, do you have any advice for a cheaper handheld GPS? Christmas is right around the corner and seems like a good idea.....

Yes...... I have had a version of the following handheld gps for over ten years and it has never failed me. It is NOT a chartplotter.... you can use your Navionics app if you want to look at maps. It is a pure GPS unit that will give you all speed, course, mileage, velocity made good and basic location data. There is a trip computer that separates moving time from standing time... so if you want a more accurate average speed or distance .... this will filter out any time under 1 kt. It will also provide navigation functions such as following a course with a set of waypoints. It will also send data to your tiller pilot for navigation purposes. A dedicated marine gps will have all these features and more.... I've sent you a link also... but remember the one I've pictured is a refurbished model with a 1 year warranty. Very good price though. The model I have, GPS 76, is out of production...but continues to work perfectly. The one pictured below is the 72H. Almost identical. One great thing about these units..... THEY FLOAT. and even better... YOU CAN SEE IT IN BRIGHT DAYLIGHT!!!!

They use 2 AA batteries, but I purchased a power/data cable that allowed the unit to run off boat battery and receiver waypoint

and trip data from an external computer.
I also had a mount for it... it allowed me to take it off for storage or hand operation.... the mount made it easy for watching speed and course.

Bottom line... the marine handheld gps is your most basic piece of boating hardware.


Note... if you're willing to spend a little more, say $100, You can pick up a refurbished GPSMAP 78sc. it has built in charts, color display and all the other features of a dedicated gps.... very cool.

 

[Cincy020]

That Garmin 72h looks like a pretty good deal.

I really have no need for a chart plotter/map since I'm always on the same lake, but the Navionics app is kind of cool to see where you have been. I am interested in learning how to sail better (better sail trim) so I suppose seeing the speed on the GPS would help a lot with that. Could be an interesting purchase.

Yes, but only if your keel is in bad shape. My swing keel was cast iron, so it rusted. Not bad enough to flake, but very pitted. I sandblasted it an painted it. I found it made a very noticeable difference. while drag is an issue, what is probably more important is that if the surface is poor, the water will not stick to it, and it will stall. At that point the boat slips sideways.

Did you just sandblast and paint, or did you fair as well? My is pitted/flaking and needs some work. Thing is I really don't have either the room or time to completely fair the keel.

 

[Daveinet]

I did not fair it. The surface after painting still was textured, but the sharp edges of the pitting where masked by the thickness of the paint. I did not want to fair it, as I wanted the paint directly on the metal surface. The paint was cold galvanizing paint. It basically looks like the typical textured surface of cast iron.
Not that it influenced my decision to not bother fairing it, I've always wondered if a small amount of texture could be of benefit. After all it works for golf balls.