cheapest way to fit speedo

[Guest]

my tracker has got no speedo, it has an old analog but not working. what is the easiest way and cheapest to fit a speedo

[Fusion 0]

Hand held GPS = SOG

[Guest]

whats the diff between SOG an SOW

[Absolution 7]

whats the diff between SOG an SOW

 

The tide!

[wheels 543]

And slip

GPS will give you your real speed over ground with real direction, not just the direction you are pointing.

[Atom Ant 0]

Trouble with GPS is that you're not going to get an accurate indication of your boat speed from one tack to the other. But that really only matters if you're racing. If you're cruising, who cares if you're .1 of a knot down on one tack compared to the other.

 

There's no cheap way of doing it properly clint d. But there are ways you can minimise your costs. For example you may never need a multiple display option if a speedo is all you'll ever need. Having said that speed/depth is pretty standard these days and it's worth having them on the one display. I'd suggest you don't go too cheap as you only ever get what you pay for.

[wheels 543]

But you have to have a GPS for that anyway don;t you AA. And Windindicator. Then the three combine and compute the variations.

[Atom Ant 0]

Well no Wheels I don't think you need a gps for calculating true boatspeed from one tack to the other, or a windicator for that matter. The electronic windicator will give you your true or apparent wind angles which are necessary if you wish to make a polar across all wind angles, but if you wish to simply check your boatspeed say, from one tack to the other when you are hard on the wind, then a windex will do the trick and it will be close enough if you're going low cost. I admit the goodies are good to have but they're not absolutely necessary for your average boatie who does a bit of cruising and a bit of fun racing.

[wheels 543]

RightyO. So what could change that speed then. Is it a case of the wind is "better" somehow in one direction than the other? or are you using it to get check if you have the best sail trim etc?

[Guest]

All sorts of things can cause the difference, but knowing it is there is the first step to finding the cause.

[Guest]

Cheapest speedo?

 

Matchstick and cheap Japanese watch.

[Guest]

Cheapest speedo?

 

Matchstick and cheap Japanese watch.

what

[col j 0]

match stick, cheap watch and a calculator. or just do it in boat lengths. time on distance

 

but id have to say that the cheapest way to fit one is to fit it yourself if you know what to do.

[wheels 543]

You may as well tow a piece of line with knots tied in it then.

[Farrari 4]

Your two generic options are either a paddlewheel type that measures your speed through the water (Speed Over Water) or a GPS unit that will measure your Speed over Ground. It depends on what you want to use the yacht for as to whether you would have one, the other or both. For crusing or casual racing either is fine but you don't need both. In my tracker I had the paddlewheel but the instrument didn't work. I didn't bother getting it fixed but rather got a small chartplotter installed. The chartplotter was magic for cruising, especially if you had to shift bays at night.

 

If you have a paddlewheel already installed your cheapest option might be to find an instrument that is compatible with it. Try putting an advert in the classifieds and see what pops up, otherwise there is always Trademe.

 

As an addendum, Speed over Water measures how fast the water is moving past the vessel. If you are punching into the tide it will read higher than you are actually moving over the ground as an example. Speed Over Ground measures how fast your vessel is moving relative to the ground (think seabed) irrelevant of the tide.

[Guest]

draw a circle on cockpit bulkhead, write numbers round the outside of it ( however many you like) draw a line tween the centre and zero, when your family frightener is parked in the drive at home it is guaranteed to be 100% accurate, no errors, no variations.............you'll never get the same result with a working one..........

[Guest]

You may as well tow a piece of line with knots tied in it then.

 

Like 5 or 6 knots? Hmmmmm... I wonder where that came from.

 

Clint d - I was not trying to be facetious. Time x distance - drop match in water at the bow and time it over the (known) length of your boat (18.52m would be good ). A bit of maths and you have speed through the water. Not very good for racing, but has been done by many cruisers (after their log and back-up logs have been eaten).

Cheers

[PaulR 3]

Somewhere on the net recently, i read comments about testing if an impeller is working. Google it.

 

What brand is your log?

 

Most of the log impellers (and depth transducers) are made by www.airmar.com and sold under different brands. They have a good cross reference and wiring diagram section.

 

Two basic log types:

 

One emits a pulse and the paddle wheel (impeller) with a small magnet in one prong passes under a wiring loop to make a pulse. The more pulses per minute, the faster you are going! The instrument has the electronics to convert the pulses to analogue (dial) or digital output LCD display.

 

The other type has some electronics in the impeller unit so it sends "smart" electrical signals to the displays. You would be best using the same brand in these cases.

 

Some systems have a box of electronics between the impeller and the display.

 

A third type is a combination of Speed, Depth and Temperature known as a "triducer".

 

Skin Fittings come in a few different sizes, but most transducers fit about 3 different diameters. Some transducers can work with different brands. Some work on 12V but others use 50V pulses (JRC). So it's important to check properly before connecting.

 

Some brands (Tacktick) put inserts in to the skin fitting to reduce the diameter of the hole.

 

So the first step is to measure your existing log impeller diameter and see which brands and thus costs are available to you, before you go for the added costs of changing a skin fitting.

 

FYI, the Nexus Triducer has a flapper valve that reduces the big gush of water when the log is removed to a small trickle so you can take a minute or so fitting the blanking plug after sailing and don't need to panic quickly. It really is a great step forward.

 

BTW, it could be your wiring from the log to the instrument that is faulty. Had to renew that wiring on one boat in the last few weeks. Now no problems.

[John B 106]

Those valves take all the theatre out of it. It's nice to wind up 'the crew' when you have the one inch bolt of water powering in. quick, quick'(makes smothering attempt)... ' What!'

get a beer bottle... no no ..open it

 

cheers ears.

[Guest]

It's not a cable driven log is it?

I took one of them out of mine last year. The head unit still worked, but it kept getting damaged by the travelift underwater.

The marks to indicate where to put the strops were on the wrong side of the yacht for the operator.