Can someone explain radar to me please...

[lustyd]

comes as standard with both touchscreen and physical controls.

If it's still installed, have a play on it to see how responsive those feel. It may not be that long ago, but plotters were pretty laggy until very recently, and some brands still are.
It does take MicroSD and has a choice of chart vendor, so at the very least you can get charts for it for the foreseeable future.

 

[dunedin]

If it's still installed, have a play on it to see how responsive those feel. It may not be that long ago, but plotters were pretty laggy until very recently, and some brands still are.
It does take MicroSD and has a choice of chart vendor, so at the very least you can get charts for it for the foreseeable future.

A non faulty Raymarine e97 will be pretty fast responding.
But yes worth viewing whilst still operating if possible.
Further to my previous suggested checks, hopefully the control toggle should feel reasonably firm, not loose or floppy.

 

[Sea Change]

It's no longer installed, but the seller seems very friendly (the sale of the plotter only came up after we'd been talking for a while and he was offering to help me with other things).
I'm sure he'd be happy to let me hook it up to a power source.

Also, looking at images of the connections, it appears that the e97 has NMEA0183... which would be very helpful because it saves me buying an adapter for my AIS.

What's the WiFi functionality like on these? Does it do all the things that the Axiom does?

 

[Dockhead]

It's no longer installed, but the seller seems very friendly (the sale of the plotter only came up after we'd been talking for a while and he was offering to help me with other things).
I'm sure he'd be happy to let me hook it up to a power source.

Also, looking at images of the connections, it appears that the e97 has NMEA0183... which would be very helpful because it saves me buying an adapter for my AIS.

What's the WiFi functionality like on these? Does it do all the things that the Axiom does?

Your AIS doesn't connect via NMEA2000? I haven't seen one like that in more than a decade.

If you still have an old Type B, it's very much worth upgrading to B+ SOTDMA, which is vastly better.

 

[Sea Change]

Your AIS doesn't connect via NMEA2000? I haven't seen one like that in more than a decade.

If you still have an old Type B, it's very much worth upgrading to B+ SOTDMA, which is vastly better.

It's an ONWA, class B+, with 7" screen. Does fine as an AIS but makes a pretty poor plotter. To the point where we just really use it as a GPS readout (SOG/COG/pos) and as an AIS display.

 

[Sea Change]

So as I see it:

e97: cheaper, physical controls, 0183+STNG

Axiom: more expensive, touchscreen only, would need an 0183 converter. But it's newer, faster, and likely to be supported for longer. I'd have a warranty, although I'm not sure how worthwhile that will be with a DIY installation and the boat moving around internationally.

A friend upgraded from e series to Axiom and said it was quite a lot faster. I'll maybe try both out before I commit.

 

[PaulRainbow]

Your AIS doesn't connect via NMEA2000? I haven't seen one like that in more than a decade.

If you still have an old Type B, it's very much worth upgrading to B+ SOTDMA, which is vastly better.

Vastly better how ?

 

[Dockhead]

Vastly better how ?

Well, let me count the ways.

1. Transmits at 5 watts vs 2 watts
2. Updates every 5 to 15 seconds under way vs. 30 seconds.

but most importantly:

3. Uses SOTDMA system like Class A to reserve a time slot, so has a right to be heard.
vs. the obsolete Class B CS (Carrier Sense) which has no right ever to any priority, does not participate in SOTDMA, and can transmit only in gaps when no one else is transmitting.

The last thing is why old Class B sets frequently just disappear in crowded areas.

"Vastly better" is most definitely not an overstatement here. Anyone still using an old Class B CS set would be well served by chucking it and updating to the new standard.

 

[lustyd]

The last thing is why old Class B sets frequently just disappear in crowded areas

Why does this matter? In crowded areas ships won’t be using AIS to avoid you, they’ll be using regulations (RAM, exclusion zones etc. ) for you to avoid them. Ships already had priority so you could see them on AIS even when busy. .

 

[Dockhead]

Why does this matter? In crowded areas ships won’t be using AIS to avoid you, they’ll be using regulations (RAM, exclusion zones etc. ) for you to avoid them. Ships already had priority so you could see them on AIS even when busy. .

The point of broadcasting AIS is to improve your chances of being seen. If your transmissions get some priority, these chances improve a lot. Of course this is not as important as following the Rules.

A well-run ship's bridge will be using radar and eyeballs as primary systems, and AIS just as a supplementary system, but yachts don't show up all that well on radar, especially if we are close (their radar antennae are high), so AIS is an important backstop. I've heard over and over again from professional mariners that they consider seeing us on AIS as important (over and over again, they say they want two things from us: 1. follow the Rules; and 2. broadcast AIS). If we accept that, then it's important to use a type of AIS which gets some priority in the SOTDMA system, and the obsolete Class B does not.

Also it's often not only a matter of "us avoiding them". In many situations, we are obligated to stand-on, and in that case they need enough information about us to do what they need to do. And even if they are standing on, they will want to know whether we are taking adequate action, or not. Radar is almost 100% effective with other ships, but not with yachts, so the information they can get from seeing us on AIS can be critical.

I'm surprised you mention RAM, which is very rarely a factor in our encounters with ships. In my own lifetime of sailing, I can recall crossings with vessels in RAM status only 4 or 5 times.

 

[lustyd]

In busy waters, they're not using AIS for collision avoidance. It also doesn't improve your chances of being seen in the real world since in busy waters the additional transmission power is irrelevant and closer targets show up anyway - that was part of the reason for limiting power in the first place. It's just a non-issue in real actual sailing scenarios.

You're technically correct that technically it offers slightly superior range and priority, but again in the real world it's never been an issue and it's worth an upgrade over a working older set unless there are other factors. I would get B+ if cost was the same and I was upgrading anyway, but it's not worth a premium and it's not worth going out of my way to change.

Every ship in the Solent is RAM, hence the exclusion zones! Any ship in a channel in a busy sailing area would be similar - they can't alter course to avoid yachts because that would cause a different collision situation or would mean leaving the channel.

 

[Dockhead]

In busy waters, they're not using AIS for collision avoidance. It also doesn't improve your chances of being seen in the real world since in busy waters the additional transmission power is irrelevant and closer targets show up anyway - that was part of the reason for limiting power in the first place. It's just a non-issue in real actual sailing scenarios.

You're technically correct that technically it offers slightly superior range and priority, but again in the real world it's never been an issue and it's worth an upgrade over a working older set unless there are other factors. I would get B+ if cost was the same and I was upgrading anyway, but it's not worth a premium and it's not worth going out of my way to change.

Every ship in the Solent is RAM, hence the exclusion zones! Any ship in a channel in a busy sailing area would be similar - they can't alter course to avoid yachts because that would cause a different collision situation or would mean leaving the channel.

If they don't use AIS for collision avoidance, that doesn't mean they don't use it to detect your presence if they can't see you and you're not showing up on radar. The advantages of the current Class B+ class of AIS in that are not indeed "slight", but very great.

"Every ship in the Solent is RAM" -- this is false. You need to brush up on the COLREGS, man. RAM status ONLY applies to vessels which "by the nature of their work", i.e. dredgers, cable-layers, surveying vessels, etc., are unable to maneuver as otherwise required by the Rules (see Rule 3(b)), and RAM status ONLY exists if RAM signals are shown (red-white-red; ball-diamond-ball; Rule 27).

In the Solent, or rather in the approaches to Soton Water, in the Needles Channel, and in other narrow channelized areas, the Rule you have to be careful about is Rule 9, Narrow Channels. Vessels under 20m and sailing vessels must "not impede" other vessels navigating in narrow channels and which cannot navigate safely outside them.

This Rule works differently from RAM, NUC etc. status. You "do not impede". This is different from giving way under Rule 18. I could explain why, but I normally take money for that, or at least beers.

In certain parts of the Solent, you have MPZ's and local rules to worry about, on top of that.

If you sail only in the Solent, then you don't need any kind of AIS, and probably you can get away without much understanding about the COLREGS. To deal with ships, just stay out of the buoyed channels. Don't hit other yachts. The Solent is not the ocean.

 

[lustyd]

If they don't use AIS for collision avoidance, that doesn't mean they don't use it to detect your presence

We're talking busy waters here, they aren't using AIS. My entire point was that in busy waters it's irrelevant and in quiet waters it doesn't make a difference.

If you sail only in the Solent, then you don't need any kind of AIS

Simply not true. I explained previously the benefits to the user of AIS in such waters. We sail all over the place (and live aboard) so I feel well placed to address the subject.

 

[Dockhead]

We're talking busy waters here, they aren't using AIS. My entire point was that in busy waters it's irrelevant and in quiet waters it doesn't make a difference.

Simply not true. I explained previously the benefits to the user of AIS in such waters. We sail all over the place (and live aboard) so I feel well placed to address the subject.

Have you been on the bridge of a commercial ship passing through the Solent?

I have. Of course they look at AIS. Following Rule 5, they use "all available means" for situation awareness. Just because it's secondary to radar and eyeballs doesn't mean they don't look at it. If you haven't been on the bridge of a commercial ship in heavy traffic, you might also not know that most of them (especially on aft-house vessels, as most of them are) can't see anything ahead as much as a shiplength ahead, sometimes more. Their radars also don't work at those ranges. So AIS may be the only way they can detect and track a yacht which is close by and ahead.

So of course AIS is a good thing to have wherever you sail. I only meant you could get by without it in the Solent, not that it's not a good thing. As I said -- commercial mariners want JUST TWO THINGS FROM US: 1. Know and follow the Rules (and certain posts in this thread prove once again that many of us lack even elementary understanding); and 2. broadcast AIS.

 

[lustyd]

I have

I assume you were hoovering, based on your comments here.

 

[RunAgroundHard]

I assume you were hoovering, based on your comments here.

Fastidious cleanliness may explain some of the large vessel collisions, being unable to hear the close proximity alarms due to the vacuum cleaner noise.

 

[Dockhead]

I assume you were hoovering, based on your comments here.

Charming!

 

[PaulGooch]

Well, let me count the ways.

1. Transmits at 5 watts vs 2 watts
2. Updates every 5 to 15 seconds under way vs. 30 seconds.

Only time it ever transmits at 5 sec intervals is if you're exceeding 23 knots. At 14-23 knots it's 15 secs.

Everything else is exactly the same as Class B

 

[Dockhead]

Only time it ever transmits at 5 sec intervals is if you're exceeding 23 knots. At 14-23 knots it's 15 secs.

Everything else is exactly the same as Class B

It's true that the transmission rate is variable.

But it's not true that everything else is "exactly the same".

Transmission power is 5 watts instead of 2 watts.

And most importantly, SOTDMA vs. CS.

 

[PaulGooch]

It's true that the transmission rate is variable.

But it's not true that everything else is "exactly the same".

Transmission power is 5 watts instead of 2 watts.

And most importantly, SOTDMA vs. CS.

I was replying to your claims about transmission intervals, nothing else.

You said "Updates every 5 to 15 seconds under way vs. 30 seconds."

That's not true unless you exceed 14 knots or 23 knots.