Plotter, explain if you will..

[z1plex]

Dear All, in my frustration at having to wait now for my boat, i've been trawling through various mag's and on the net, looking at various items I will need when the boat is with me. One of the items that seems to crop up on virtually every forum or advert for a s/hand boat is a Plotter. I have a hand held Garmin GPS, and find it works well once you've marked your waypoint, takes you back every time as it should, without fail. I'm unsure if you can enter co-ordinates in advance, the only way seems to be to mark a waypoint and then ammend to whatever other co-ordinates you like,i.e. ones for a wreck/drop off whatever but like I say, not sure if that will actually work. My question...and if it gives you a laugh then, hey ho!, is...how does a plotter work, are the cheaper ones worth considering, are they vitally important or can you do without??, ignorance I know, but you guys have given sound advice before so can you again please.

Also, the previous boat I had was used for trawling and drifting, whereas the new boat will obviously be at anchor in the Channel.... in time, what length of chain would you recommend and what anchor type?, any advice greatfully rec'd.

 

PS, how's the comp' with the Burnham boys coming along??, anything sorted??

 

Regards to you all,

 

Duncan.

[Newboy]

Can't help you with the plotter bit, as I want a plotter too, but can't quite convince myself to part with

[Maverick Martin]

Duncan

 

An ordinary gps will do the job of navigation but you have to input all the waypoints/marks yourself. Most of us used to run on gps alone as plotters were not around then, and to be fair it worked fine. When plotters hit the market I thought no way am I going to pay for one of those new fangled things but peer pressure finally made me give in and I got the latest must have toy. WOW what a difference. Its just like having an electronic chart there in front of you. You can look at the chart put your cursor on a fishy looking bit of ground and go to it. If the fog comes in you can easily navigate your way back home whether you have input waypoints or not, cause you you have the chart there in front of you.

Regarding price, it depends on your budget all I will say is that colour is better than monochrome and you should try and buy as big a screen as you can afford. On the smaller screens your unit will need to rewrite more frequently.

 

Regarding anchors most of us around this way use a Bruce style. These are very good for holding in all types of bottom except for very rough ground, a 5 kilo Bruce would suit your boat. For very rough ground a fishermans or grapnell would be best. You should have at least one boat length of suitable chain 6 metres for your boat would be fine and at least 3 times the depth you intend to fish. I would suggest that 10mm warp would suit you or maximum 12mm thick. Bear in mind the more rope you buy the cheaper it becomes, I usually buy a whole coil which is 220 metres. If you source it from a supplier that serves commercial fishermen you should be able to buy it very cheaply. An Alderney ring (available mail order)and 30/35cm bouy would complete your anchor needs.

 

Martin

[great white]

Hi

 

Regarding the plotter, they are a great bit of lit for showing you on the screen where you are and where your fishing spots and safety points are {Waypoints}

a basic one does that on a blank screen [which are available on most gps sets now.]

 

A GPS unit tells you where you are with a fix from several satalites and will also allow you to enter waypoints. they usually give distance and course to the waypoint. so assist navigation

 

A Chart plotter takes a cartridge and actally shows a chart of the area, the latest ones are colour and the screen looks like a chart.

the waypoints are shown on the chart as is your position and track line.

 

I have a colour one and its a great piece of kit, a bigger budget would have got a bigger screen and more pixels but this one cost enough. and on top of that you have to buy the chart of your fishing. If you travel around a lot thats a lot of money on cartridges.

 

Basically you do not even need a navigator but not many of us would go without one now, the plotter is the next step up and the colour Chart plotter the top of the tree.

[That is unless you want to interlink a plotter to a radar screen and an auto pilot.}

 

 

The anchoring in your area you need a good anchor, Bruce, Danforth or CQR a length of heavy chain at least as long as the boat and a warp of about 12mm that is long enough to be 5 time more than the deepest water you will anchor in.

 

You will need 5 times on a choppy day in the tides around sandpoint, Brean Down or the Holmes.

 

To lift it up we usually use an alderney ring and tow it out, in the bigger tides at WSM that would be important to learn. due to the heavy mud on the bottom in the channel you may also want to rig the anchor to trip out or you may struggle.

 

This method has been covered in the magazines recently so you should be able to read up on it, although it would be better if you found someone to show you.

 

Hope this helps

Charlie

[duncan]

can't resist trying to shorten some of the above - all of which I agree except the chain bit (see later)

 

GPS gives you your position as coordinates

 

you plot these onto a chart to find out where you actually are, or from a chart to the GPS to tell it where you want to go (as you point out most allow you to store your current position at any time as a shortcut to this process)

 

a plotter, and most are GPS/Plotters but we have go so used to them they are now called plotters, does both steps at once and plots your current position onto it's electronic record (chart) of the area and displays the result to you looking like a chart on your screen.

 

the more detailed the resolution and the more colours or shades of grey available the easier the image is to read and understand quickly. Older colour plotters don't enable you to spot contour lines as easily as Black on white but they show up the land much better (green not blue!). Not an issue on any new unit I am aware of on the market right now.

 

re chain 1.5 times boat length is commonly listed and I would have thought 10m of 6mm chain to a 5kg bruce a good setup and not too heavy to handle easily. add 3 times the greatest depth you plan to anchor in as an absolute minimum but 5x would be my guideline. hte M and claw Bruce copies are cheap in that size, and I wouldn't pay the premium for a forged anchor, but I would pay out for a roll of 10mm anchorplait.

[z1plex]

Thanks chaps,...........that sort of sorts me out, i've checked into it a bit more and it appears I can download from PC to GPS via an appropriate lead, just have to delve a little further to get my head 'round it! , still it's assuring to know that, although not the best option, it still seems adequate for starters....I doubt i'll be straying too far afield in the first few instances anyway .

 

All the Best,

 

Duncan.

 

[Adam F]

Duncan,

 

If you have a serach around on the net - you will be able to find a downloadable instruction booklet for your handheld GPS - I have done twice in the past, this will make understanding how to use it easy.

 

I cant really add anything to the above. I used to run with just a handheld, then I got fed up with the battery issue and trying to hold / support the unit and steer, and when in a rough sea a small 1x2" screen is hard to see!

 

Then I went to a Garmin 128 GPS - Fixed, this was a lot better and enables me to do pret much everything I wanted expect navitage in the fog, dark etc..

 

I also put off buying a plotter as I couldnt see the use in them - until I tried one out on a mates boat, then I was hooked. Nowadays I couldnt do without it.

 

If you want you are welcome to have a trip out with me and play with a few of the toys?

 

Adam

[domino]

Duncan,

 

If you want to get a feel for what Chart Plotters have to offer, Lowrance have downloadable simulators for most of their products - HERE.

 

Remember the London Boat show is on the horizon and there are deals to be had... I have just bought a Garmin 182c colour plotter, at the So'ton Boat Show (from MES Ltd, Bristol), complete with Chart cartridge, for just a few pounds more than the cheapest internet price for the plotter alone.

 

Cheers,

Alan

[z1plex]

Cheers for the advice guys, and thanks for the offer of the trip out Adam, time allowing I may take you up on that..........I've purchased a lead in order to transfer info to and from laptop/GPS and have had some fun entering waypoints whilst out and about and also entering waypoints of wrecks etc along the Chesil area via a sheet full of co-ordinates then viewing on a web map, it's suprising just how much info' is available if you dig a bit! The GPS will just have to do once i'm on the water for a while but i've been looking at some of the types and sites that have been mentioned and they do look the business I must admit, very nice! I managed to find a cheap power lead also, so at least there won't be any issues on the battery front as it will be plugged into an accessory point.

 

On the subject of the ongoing saga of which boat, where, how, what , why because and so on....i've actually put a deposit on a new Samurai which will be available for collection in about 5 weeks, so the deed is well and truly done this time,a little sooner than I thought as at one stage it looked like a long wait. However things like plotters etc will have to wait a while...the costs of lights,radio,rope,anchor,etc,etc,and oh yeah that as well , is mounting rapidly but i'm getting slowly but surely there. Very much looking forward to me and a mate spending a weekend fitting her out, should be fun

 

Cheers for now,

 

Duncan.

 

 

[Adam F]

What happened to the predator Duncan?

[z1plex]

Adam , I had been told by many that the boat was relatively an unknown quantity, in fact David at Ainsdale had mentioned the price was so low as to get the boat out on the water to see how they were recieved generally. I decided against the Predator in the end as I found people generally, mainly dealers, were less than complimentary and mentioned problems with 'handling characteristics' more often than not.........whether this was scaremongery I don't know, and I don't particularly care much now as i've got the Samurai on the way. I have spoken at length to a friend of a friend of...you get the idea, and found that the Samurai was closer to the original boat I had decided to go for, the Explorer, than the Predator was , also it's fairly well built and tried/tested if you like. I must admit that costs came into it in the end and the Samurai was very close in price to the Predator, i.e: approx

[Newboy]

Are you absolutely sure you wanted a samurai?

 

I'm sure most of us have been there like you have, 6 against 1/2 dozon

[Swainiac]

Guys, reading through this thread, may I ask a question?? Is there a magnetic variation on charts, as there is on OS maps?? If yes, how much do you allow for vairiation when plotting to your systems on board? Sorry if its been covered before.

 

Rich

[Coddy]

Guys, reading through this thread, may I ask a question?? Is there a magnetic variation on charts, as there is on OS maps?? If yes, how much do you allow for vairiation when plotting to your systems on board? Sorry if its been covered before.

 

Rich

Hi Rich

 

Yes there is information on the magnetic variance shown on the map, see the compass rose on any admiralty chart. This was about the 7 degree mark in the UK but this does change over the years and position in the world.

 

The important thing is that you must decide what format you intend to use, i.e. 'Magnetic' or 'True' positional co-ordinates.

 

The Coastguard's seem to use 'True' readings i.e 45 degrees 'True' of Poole entrance, however you must set your GPS up for 'Magnetic' or 'True'.

 

You can always change from 'True' to 'Magnetic' or visa versa on the GPS/Plotter without re-entering co-ordinates.

 

Remember that if you use a compass to go in a direction this will ALWAYS be in 'Magnetic' and if your GPS is set up for 'True' settings it will show a small differance.

 

This all sounds a bit confusing having re-read my message but in the end you must decide which setting you will use and set the rest of your electronics to the same.

 

Regards

 

Coddy

 

[domino]

Guys, reading through this thread, may I ask a question?? Is there a magnetic variation on charts, as there is on OS maps?? If yes, how much do you allow for vairiation when plotting to your systems on board? Sorry if its been covered before.

 

Rich

Rich,

 

Yes, the lat & long lines on paper charts are drawn to True North, as on land based maps.

 

At several places on a paper chart there is circle printed, marked in degrees (0-360), which you would use in conjunction with a parallel rule, or Portland Plotter, to plot your course... from the centre of the circle is an arrow showing the correction which needs to made when transferring the course to a compass.

 

The one I'm looking at shows 4 deg 45' W (1988), decreasing 7' E annually.

 

All chart plotters / GPSs that I've come into contact with have the ability to set them up to display bearings / courses relative to True or Mag North... and if you select Mag North then you have to enter the correction proper to your location.

 

In reality with a chart plotter it is not really an issue, as you point the cursor to where you want to go and then follow the track as drawn by the plotter... whether the plotter shows True or Mag is neither here nor there.

 

It only becomes an issue if the plotter goes wrong and you need to navigate home using a paper chart and compass!!!

 

Much more important is to make sure that your plotter / GPS is set to the same Chart Datum as your paper charts, if you are transferring marks / waypoints from one to the other.

 

For many years (well since 1936 I guess) UK charts were drawn to the OSGB36 Datum (Ordnance Survey Great Britain, 1936) and all plotters / GPSs sold in this country will have the option for using this datum.

 

The default for Plotters is WGS84 (World Geodetic Survey, 1984) and I believe newer UK charts are also using this.

 

I believe the difference between the two is in the region of 175m... although I am happy to be corrected on that, if anyone knows better?

 

Hope this helps.

 

Cheers,

Alan

[Coddy]

Hi Duncan

 

Good luck with the new boat.

I looked at the Samurai before buying the Warrior I too think they are a good looking boat.

 

I am sure you will be happy once you get it and start fitting it out.

 

Regards

 

Coddy

[Bob F]

Yep, good luck with the new boat.

 

The Alaska I got from Arnie has proved its seaworthiness so I expect the Samurai to come put of the same mould (excuse the pun ). Being hit by a huge wave beam on and tilting to 80 degrees without tipping over has got to be a pretty good test.

 

Doesn't say much for my seamanship for putting her in that position in the first place, but that's another story...

 

Bob F.

[Swainiac]

Guys, thanks for the input........it appears that the magnetic variation system is the same for both land and sea. As an accomplished naviagtor on land, I am now burrying my head in books with a view to attaining similar qualifacations at sea, which will only help me when I eventually seize the opportunity to purchase my own vessel, which hopefully will not be too long..........just glad Debs doesnt log on to this forum!!She'll kill me!

 

 

Rich

[Brian]

I use OziExplorer on an old Laptop, connected to my Garmin 128, as a plotter, Got Poole Harbour and Poole Bay charts. Works brilliantly, I store every track (trip).

Using Paint Shop Pro I can update the charts, if a navigation buoy is moved etc.

[Coddy]

I use OziExplorer on an old Laptop, connected to my Garmin 128, as a plotter, Got Poole Harbour and Poole Bay charts. Works brilliantly, I store every track (trip).

Using Paint Shop Pro I can update the charts, if a navigation buoy is moved etc.

Hi Brian

 

I looked at that programe but could not see if it would work on C-Map NT+

 

Regards

 

Coddy