Question on electronics from newcomer

[Joe Myerson]

One of the most useful features of a GPS is to give you a pretty good idea of your Speed Over Ground (SOG). In some regards, a GPS is too sensitive for use on the ocean, as you'll see that the SOG fluctuates as your boat slows down as it climbs waves and speeds up as it slides down the other side.

But it still beats those little paddle-wheel speed logs that get gummed up by seaweed (they do help determining current drift and/or set).

And, if you're worried about battery use: turn your little GPS on once an hour, get your position and mark it on your paper chart.

--Joe

[Neil Gordon]

In my experience, if you start with a reasonable estimate of location, and allow +/- 20 feet or so for tide, given the fact that chart depths don't measure every single bump and dip on the bottom, you can verify that you're in about 120' of water and not 60'. That +/- 120' area can be quite broad. As for following, say, the 60' or 30' line into a harbor, that can be a twisty experience when motoring, even trickier under sail, and you could be toying with rapidly shoaling water. Sailing single-handed vastly complicates this.

Locally, we have about a 9' tide and it's easy enough to know the times of high and low. I suspect accuracy within just a few feet, for the most part.

Navigating depth contours to make landfall, it can be more important to know where you're not than to know exactly where you are.

Here's a good application, with limited visibility:

Say your entrance channel is 25' deep, deep to seaward, deep to starbboard until you hit the rocks but gently sloping from 25' to shore to port. The 25' curve on the port side will lead you safely into the harbor.

If you try for the harbor entrance and miss to the right, you're in trouble. So steer left to be sure you're on the easy side of the entrance. Then follow the depth curve... between 20 and 25.

[trapper]

My husband and his friend just finished refitting a Ty weekender and she is beautiful. I will have to post pics.

They installed a Raymarine ST40 depth with thru hull transducer. IMHO, you need to use the good stuff when you cut holes in the boat. He is using an electric motor and the boat has lights so they installed a 2 battery system. They had a solar panel when the boat was on a mooring. The first one was a hard one and it lasted almost a week before it was stepped on and broken. Now they have a roll up one. The boat is now at a dock so they have installed a small electric trickle charger and a small shore power plug. He uses a handheld radio and handheld gps (etrex). The gps is just for speed as gps navigation is not needed on the lake. He also has a laminated paper chart of the lake on board. No compass (except for the gps). He pretty much has everything he needs.

[Dick Kobayashi]

but in the ten years I have had Susan B I have carried the Garmin MAP 76 on board. Each year, at the beginning of the season, I buy a box of 20 AA batteries - the best I can find. They power the GPS and I always have 5-8 left over at the end of the season which I put to use on shore. This way I am never without power for my GPS. Possession of 20 AAs lends a feeling of security and I don't have to be conservative in my use of the GPS. btw a single pair of AAs lasts about one full sailing day.

[Carl Thunberg]

Dick,

Funny you should mention that. I keep my handheld GPS on 100% of the time. I don't do it for navigation, but I like the statistics it stores. Anyway, one set of AA's for one full day of sailing is about right. It goes without saying that you should multiply that by three when you're offshore 24 hours/day. I failed to make that seemingly obvious calculation when we went to Nova Scotia this summer, and ran out of AA's . Fortunately, Dean bailed my sorry butt out.

[bottomscraper]

I believe the fine Garmin GPSMap 76CX has been discontinued (although you can still buy them online) I think the GPSMAP 78 series has replaced it. You may find it cheaper to go with a unit with preloaded maps rather than a separate card. For example the GPSMAP 78sc has preloaded coastal maps.

Another option might be something like the Garmin GPSMAP 441s. This is a small fixed mount unit with built in maps and depth sounder. I believe you can buy it with or without a depth transducer, they have several types of transducers available. You end up with a bigger screen and a depth sounder for about the same price as the 78sc hand held. The down side is now you need a 12V battery and some way to charge it. (Then you might as well add a fixed mount radio with a mast mounted antenna )

[Neil Gordon]

btw a single pair of AAs lasts about one full sailing day.

They last a lot longer if you use the GPS for a fix and then turn it off. That tends to be my practice on longer coastal legs where a bit of set and drift won't get me into trouble.

[Dick Kobayashi]

...TWO twenty packs per season

[tom ricks]

This is really helpful--I appreciate it.
Best,
Tom

[SurryMark]

I failed to make that seemingly obvious calculation when we went to Nova Scotia this summer, and ran out of AA's :oops: . Fortunately, Dean bailed my sorry butt out.

An aside: Carl, did you go from Boothbay to Nova Scotia in a Rhodes 18?

[Joe CD MS 300]

No one has mentioned it so far but being on Penobscott Bay your are in all likelihood going to find yourself getting caught out in the fog on occasion. It would be great to have the skill and experience to be able to navigate comfortably in the fog but that will take time. Until you do it would almost be unseaman like to venture out without a GPS on the Maine coast especially given the relatively small cost of units today. You are not going to head out with out a VHF radio are you? GPS should be in the same category as VHF.

You should work on the skills needed to navigate with out electronics but have the electronics on board as a check and when you will really need it like in the fog.

[ronkberg]

Tom, I have a depth sounder mounted inside my Ty, use an older Garmin 176C, a mounted VHF radio and have a small solar charger for my small 12V battery.

The depth sounder keeps me off the sand bars in the river where I am moored but has many false alarms when bubbles flow past.....or seals investigate.

The Garmin keeps a lot of data as stated above and is good to see where I've sailed. The image is difficult to see in bright sun but I do not rely on it as I sail in local waters.

I test the VHF radio each time I go out such that it is ready if needed for emergencies, then turn it off.

The solar charger came with a VW I bought in 2007 that was shipped with all VW's back then. I leave it tied down on my cabin roof while on the mooring and stowed when sailing. My battery stayed topped off all through the summer, but I do not use radio or GPS often so just the depth sounder draws current.

Have fun with your Typhoon, they are great little yachts.

Ron

[Carl Thunberg]

I consider myself a pretty adventurous guy, but I don't think it would be a prudent decision for me to sail to Nova Scotia in my Rhodes 18. The reality is, the boat is seaworthy enough that it could probably make the trip and arrive safely, but with no shelter to get out of the elements, it would not be fun. Dean invited me to crew for him on his CD31 Loda May, and I jumped at the opportunity. We sailed out of Falmouth (Handy's).