Charts & navigation

[codprawn]

Originally Posted by genoa

Yep. Absolutely. Everytime

Wasn't havin' a go at the ribsters who play safe. It was the slight at us yachties not doing things cos we got a big lump underneath!

The point is, if the conditions are right and you can read and interpret good information, you can go many places that the unprepared can't.

And when did I belittle yachties? I have great respect for someone who can handle something that has the turning circle of a battleship and about the same draft!!!

[AndyB007]

Originally Posted by codprawn

I admit I have neglected paper charts because a RIB is not the ideal envirnoment for them but seeing how lacking in detail some of the electronic charts are I will carry some in future.

Ditto. Has anyone tried the Tough Chart Folios yet? Are they as good as the paper charts for detail, and easy(ish) to use on a RIB??

Andy

ps - I'm one of those that gives Bembridge ledge a WIDE berth!!

[Biggles]

Andy,

I have laminated my Admiralty charts to A3 size. But I don't think they are any use whilst on the move unless its really calm. You really need to keep stopping to check them which sort of defeats the object of having a RIB and speeding around. Thats the main reason I take a wide berth around everything because I haven't got the time or inclination to stop and work out the most efficient route.

I get the feeling being efficient is a yachtie thing. I was on a yacht last year and got told off by the skipper when I followed the deep water channel. I could understand what he was getting at. It takes for ever to go anywhere in a yacht and every meter saved in distance travelled is a bonus.

Think I'll stick to the internal combustion engine myself. Although yacht fuel bills are a plus point and the cabin when you get to a point. Maybe when I retire !

[Doug Stormforce]

Originally Posted by codprawn

For a start my comments were "tongue in cheek".

Secondly the OS map seems to be far more accurate than even the best charts - just look at the satellite/aerial view - the OS maps are made from those.

I have noticed many times in our area(Gower) that the OS maps are much better for close in work.

So which is it-

tongue and cheek or

are you saying OS maps are better than AC charts?

I can't say ive seen OS maps with depths marked on them and if so what do they refer to? Lowest Astronomical Tide or some other datum? As far as my charts go the whole area is marked clearly with various drying heights. As has already been said different scale of charts give different levels of information.


AC chart (1:25000) shows clearly Sharpus rocks, the run, long ledge, black rock ledge and cole rock.

Its about using the correct scale of chart for the job. Bit like chart plotters. If you have bought detailed charts for your plotter you will be able to zoom in to the same level of accuracy as the AC charts

[Doug Stormforce]

Originally Posted by AndyB007

Ditto. Has anyone tried the Tough Chart Folios yet? Are they as good as the paper charts for detail, and easy(ish) to use on a RIB??

The tough charts are ideal for RIBs, by their nature they have lost a bit of deatail but are an ideal comprimse between practical size and level of detail. Intrestingly the tough chart of Bem. Ledge show long ledge with the worst drying points 2.7m, 2.9m and 3.1m

[J.C.]

Originally Posted by Doug Stormforce

I can't say ive seen OS maps with depths marked on them and if so what do they refer to? Lowest Astronomical Tide or some other datum?

Just to answer this part, OS maps show height information relative to Ordnance Datum Newlyn (unless you find a VERY old map which may have the defunct Liverpool datum shown). This datum is the agreed height datum for the whole of mainland Britain and is used on all OS products. You won't find any depth information on OS products.

The relationship between OS Datum and Chart Datum varies from chart to chart, and indeed port to port, so if you want to relate the two you need to look up a conversion value. For an example, Felixstowe Chart Datum is 1.95 BELOW OS Datum.

[Tims Osprey]

In the Bristol channel we have a tidal rise of over 14 metres on big spring tides and around 4-5 metres on neaps, coupled with that the murky 0 visibility water, sand banks all over the place that can change on a big set of springs and miles of shoreline that dry up at low water. Needles to say local knowledge is a must forget the chart plotter.

[Erin]

Originally Posted by genoa

I have not used the Garmin kit, but with Navionics and CMap the data is there, and like the paper version, it depends what you have bought. If you have paid for the detailed charts you get the detail, if not you don't. How many people on the forum have bought the detail and how many rely on the preinstalled summary stuff designed for planning not navigation?



A plotter, whether it be a digital screen or a mark on a bit of paper is NOT synonomous with navigation. The later requires you to do more including understanding tidal ranges and curves. It is to easy to think that cos you can read a TomTom in the car, that you can navigate. I know since I bought the Rib I have become more lazy than when I sail, but I still check the charted depth against reality and expected for the time to see wots wot (occassionally). These skills are vital and we must encourage people to understand them so that they have a feel for what they are getting into.

I can assure you I entirely agree. I have undertaken a number of RYA courses and am qualitfied up to Sailing Dayskipper practical for tidal waters. I fully understand tidal calculations, secondary ports and all that biz. That is not to say I use it every time I go out on my rib however. There's a major difference between chartwork on a sailing boat at 5 kts and that on a rib at 35kts. For a start, tidal streams and leeway are practically irrelevant on a planing motorboat. The point of my message was that Garmin seemed to be particularly poor at illustrating the same data as is found on a paper chart. I, and I'm sure many others too, would expect a chart plotter to display the same info of a paper chart, just in an electronic form. And I'm talking about the full Mapsource product, not the preinstalled basemap. You're a better man than me if you can drive a rib and plot your positions on a paper chart with dead reckoning etc when you're bouncing around at 30+ kts.

I have little sympathy for people that go out with little or no experience or training. I have rescued a number of people who have bought the equipment (flares VHF etc) but cannot use it and end up in trouble. Education not regulation is the answer IMHO.

Rant over

keith

[chris123]

Originally Posted by AndyB007

Ditto. Has anyone tried the Tough Chart Folios yet? Are they as good as the paper charts for detail, and easy(ish) to use on a RIB??

I looked at them, but they still only seem to cover very limited areas. I ended up getting Maptech charts on CD:

http://www.memory-map.co.uk/world_marine_charts.htm#1

And printed them out onto waterproof paper:

http://www.memory-map.co.uk/acatalog...oof_paper.html

Detail seems to match the Admiralty paper charts (attached).

Cheers

Chris

[codprawn]

Originally Posted by Doug Stormforce

So which is it-

tongue and cheek or

are you saying OS maps are better than AC charts?

I can't say ive seen OS maps with depths marked on them and if so what do they refer to? Lowest Astronomical Tide or some other datum? As far as my charts go the whole area is marked clearly with various drying heights. As has already been said different scale of charts give different levels of information.


AC chart (1:25000) shows clearly Sharpus rocks, the run, long ledge, black rock ledge and cole rock.

Its about using the correct scale of chart for the job. Bit like chart plotters. If you have bought detailed charts for your plotter you will be able to zoom in to the same level of accuracy as the AC charts

It started out tongue and cheek but the more I look at the OS maps the more impressed I am for using them to pick out coastal details.

You seem to be missing the point about the electronic charts. They are NOT all the same. You don't get the option of buying "detailed charts" with more or less detail - it's the basemap or the full chart - nothing in between. When you buy charts for a certain area that's what you get.

[chris123]

Originally Posted by codprawn

You seem to be missing the point about the electronic charts. They are NOT all the same. You don't get the option of buying "detailed charts" with more or less detail - it's the basemap or the full chart - nothing in between. When you buy charts for a certain area that's what you get.

I believe Doug was referring to the Admiralty charts, which do give a range of levels and detail. For example, looking at Bembridge on my pc, I can zoom in and out through:

BA0002 British Isles scale 1:500,000
BA2656 English Channel - Central Part scale 1:325,000
BA2045 Outer approaches to the Solent scale 1:75,000
BA2037 Eastern approaches to the Solent scale 1:25,000

However plotters for the leisure market which use Admiralty charts are very few in number (not sure if there are any) - if you want raster based charts like Admiralty ones you need a pc or pocketpc

[codprawn]

No he was talking about plotters in general.

[Biggles]

Whichever maps (Charts) you use. If your going to be out and about just study them.

At the end of the day boating is dangerous.

So take your lifejackets, killcords and flares, know how to use them and as all good Scouts say 'Be prepared'.

NR.

"Its a jungle out there". Hill Street Blues.

[DJL]

Originally Posted by Erin

You're a better man than me if you can drive a rib and plot your positions on a paper chart with dead reckoning etc when you're bouncing around at 30+ kts.

Navigating high speed open boats like RIBs is all about planning and using electronic navigation aids properly. No one is expecting people to sit on a RIB with a paper chart, a Portland plotter and pair of dividers and to ignore the GPS.

Anyone going out on a boat should familiarise themselves with the area using paper charts of the correct scale (as well as almanacs, books and knowledgeable locals) before setting out. Find out what the tides are doing - again its perfectly valid to buy the local tide books with graphs, print off tidal graphs from easytide or use the tide graphs on your chart plotter rather than drawing you own tidal curve and doing secondary port calculations.

Route planning should be done before getting on the boat. Plotting courses on a chart plotter or on computers is valid, but the routes should be duplicated onto paper charts - firstly to ensure the route is valid; it’s hard to appreciate your route on a 5inch plotter screen and second, because if the plotter fails for any reason you have your route on the paper chart.

Use techniques such as cross track error ladders to keep your position easily recorded on the chart as you make progress.


To those who say "You can't expect me to do all that just to go and potter round the bay!"

Yes - or at least the first time you do. The second time you can use the route you made for your first trip out, as well as all your local knowledge acquired from the first trip out.


I'd highly recommend an RYA intermediate course to anyone who isn't sure how to use traditional navigation alongside GPS/Chart plotters on a powerboat. It’s not a case of one or the other.

[John Kennett]

Originally Posted by AndyB007

Ditto. Has anyone tried the Tough Chart Folios yet? Are they as good as the paper charts for detail, and easy(ish) to use on a RIB??

They use a selection of chart sections which are the same as the corresponding paper charts. They are physically easy to use because they don't flap around like a paper chart, but in practice aren't as clever as they might be.

I've got the "Area 1: The Solent and Approaches" book. Although it's A3, on half of the pages the actual charts are hardly bigger than A4, with a big border and space for notes!

For me the biggest drawback is that a series of small chartlets makes planning difficult and can also be a bit disorientating (it's a bit like working with a chart plotter that you can't zoom out).

My preferred option is still a Stanfords waterproof chart folded to A3 showing the area I want, inside a ziplock bag.

As the Admiralty were kind enough to send me the Tough Chart as a freebie, if you PM me your address I'll send it to you to try for yourself.

John

[genoa]

Originally Posted by Erin

There's a major difference between chartwork on a sailing boat at 5 kts and that on a rib at 35kts. For a start, tidal streams and leeway are practically irrelevant on a planing motorboat. The point of my message was that Garmin seemed to be particularly poor at illustrating the same data as is found on a paper chart. I, and I'm sure many others too, would expect a chart plotter to display the same info of a paper chart, just in an electronic form. And I'm talking about the full Mapsource product, not the preinstalled basemap. You're a better man than me if you can drive a rib and plot your positions on a paper chart with dead reckoning etc when you're bouncing around at 30+ kts.

I have little sympathy for people that go out with little or no experience or training. I have rescued a number of people who have bought the equipment (flares VHF etc) but cannot use it and end up in trouble. Education not regulation is the answer IMHO.

Rant over

keith

We're in complete agreement here - education is a must. In my professional capacity as an educator in the corporate world, I would also cross reference the thread
http://www.rib.net/forum/showthread.php?t=20506
with niksters point, that education is not one off, but should have elements of prework (before a course) and essential is post training coaching. With driving licences for cars - you either have a licence or you don't. How about when you pass, you have to pay for a coach for 6 sessions, 1 a month after passing - to ensure you have confidence but aren't slipping into bad practise. I'd love to see some organisation offer this to us in the boating scene.
As to charkwork, I wouldn't dream of plotting regularly on a paper chart in the rib. I come back to the point about navigation being a collection of skills to safely get from A to B. As Codders said, for him it is MK1 eyeball!

I am amazed Mapsource don't give you the same detail as the admiralty - Navionics and CMap certainly do!

[Erin]

Originally Posted by genoa

I am amazed Mapsource don't give you the same detail as the admiralty - Navionics and CMap certainly do!

The detail is there, it's just not displayed as clearly or in the same fashion as on an Admiralty paper chart. That's my gripe. For example, rocks awash at CD are shown as a small ring of dots.... hardly as clear as a cross with four dots is it!

keith

[Limey Linda]

I have to agree. If you are not VERY familiar with your boating area then there is no replacemnt for spreading a full size chart out on the kitchen table and studying it for an hour or more. Then, just perhaps, you will understand what the GPS is telling you.
T.

[genoa]

Originally Posted by Limey Linda

no replacemnt for spreading a full size chart out on the kitchen table and studying it for an hour or more. Then, just perhaps, you will understand what the GPS is telling you.
T.

Very true. Ithink being able to 'remember' what you have seen on paper by refering to a chart that has similar style is a good thing. For many years yachting my fav plotter was something called a yeoman which allows a paper chart to be put in a big 'wallet' attached to a hard foam like board. You had a mouse with a cross hair on it and four arrows that light up directing you to put the cross hair where you are, taking the lat/long from the GPS. This was before the days of having a screen display of any use. But I still had it as my back up until last year.
The BIG benefit is that you can see the actual paper chart and the comments you may have written on it. You can still get the yeoman and for those doing longer trips to new areas it is a bonus. On ribs the Yeoman Sport is perfect, and can be self contained - not reliant on another GPS etc