New handheld VHF required.

[wavelength]

Besides, if it was on fire then I wouldn't be using the handheld DSC, I would still be on the boat

Oh dear more torkin bollox
Hmmm - say 90 litres of petrol onboard
you have obviously not seen as I have the damage that a half litre of petrol in a 3,000 gallon tank can do when the fitter tried to loosen an access bolt with a blowlamp. Dual compartment 6,000 gallon brand new steel underground storage tank in the hole but not yet backfilled with the concrete . The petrol had been put into the suction pipe to hold the non return valve shut during a pressure test, then released into the tank afterwards. Fortunately for the fitter he had fitted the vent to the other compartment first. Blew out the centre steel division and seared the wall for 20ft up around the vent pipe for the other compartment.
If a petrol powered small boat is on fire I'm going for the early bath option thank you

[ShinyShoe]

Originally Posted by gotchiguy

No it won't send an old position.

Icom M91 Manual - page 25 ( http://www.icom.co.jp/world/support/.../IC-M91D_0.pdf )

"NOTE: The distress call is paused for up to 15 seconds
when no valid position data is received. The distress call
is made when a valid position data is received within 15
seconds.
• If valid position data cannot be received within 15 seconds, the
distress call is made with a stored position data."

Err.. so it WILL send an old position. I dont see any menu to switch off GPS on the Icom although I may be missing it. But if not then there should only be no possition if the radio is just switched on or the signal is obscured for some reason.

Originally Posted by Channel Ribs

As Gotchi says, the Standard Horizon 851 does not suffer with any of those problems...

Unless I am mis-understanding the HX851 Manual if you've switched off GPS it doesnt try and reenable it to send the alert. So you are sinking, its cold and wet and you now have to remember to re-enable the GPS wait for a fix (38 seconds if you haven't disabled it too long ago) then hit the magic red button... ...not sure why thats "not a problem"

Copinsay reports a 38 second fix. The longer power saving modes on the HX581 switch on the GPS for 50seconds every X minutes, which makes sense. From past experience with GPSs they take longer to fix the further you've moved from the last fix, and longer if moving. Wiki backs that up (Time to first fix - Wikipedia, the free encyclopedia) - the difference between cold and warm fixes not being the length of time since the GPS was last used but the change in location/speed... So if you switch on your GPS every hour while underway at 30kts it may slow down the fix when stopped and sinking and have lost electrics on your fixed set. Although the manual does seem to think that should still be 1 minute. But I want to hit the big red button and wait for an aknowledgement not have to go through a series of menus wasting time.

I'd far rather have my GPS updating every 5 minutes than when I remember to switch it on and off. At 30kts 5 minutes is still 2.5nm or a search area of nearly 20 nm.sq A judgement of how long help will take, how easy you'll be to find (other boats make locating you difficult), what form help is likely to be*, and a potential search area (based on speed) may well mean you'd be better using a lower update time.

*a rural location with helicopter - you may be easy to spot. rural location from the water may take far longer. crowded sailing waters from helicopter you are one of several hundered boats from the water there are several hundered other boats who can help you.

Originally Posted by Channel Ribs

Even if a DSC radio were to send an old location, it would mark it as such and the speed and direction info would still be valuable to the rescuers.

I can't see any sign that the M91 transmits direction or speed information in its DSC message? Does the HX851? Does any DSC Cat D Radio? Unlike big ships RIBs tend to manouvre a lot more and change speed a lot more. Someone circumnavigating the IOW leaving the solent in a roughly Easterly direction at 30kts and hour ago could well be somewhere South of Ventnor not Poole as it might appear... OK so Solent CG have a brain and can work out that they might have a very large search area but would it not be better to have a more realistic possition in the first place.

[Channel Ribs]

You seem to be saying that even if I am right then there is still a reason not to like handheld DSC?

But FWIW and AFAIK... The data sent in a DSC message is:-

Latitude, Longitude, Date and time of fix, Course over ground and Speed over ground.

[Poly]

Originally Posted by gotchiguy

No it won't send an old position. Besides, if it was on fire then I wouldn't be using the handheld DSC, I would still be on the boat and therefore able to use flares/fixed DSC/AIS not to mention PLB permanently on my lifejacket

Notwithstanding wavelength's very good point about why an early departure from a boat on fire might be wise, even a small fire has the potential to wipe out all your on board electrics. Might I ask why you have have a DSC handheld if you always plan to be on board the boat with a working radio and a PLB on your person as a backup if you go for a swim?

Originally Posted by Channel Ribs

You seem to be saying that even if I am right then there is still a reason not to like handheld DSC?

But FWIW and AFAIK... The data sent in a DSC message is:-

Latitude, Longitude, Date and time of fix, Course over ground and Speed over ground.

Course and speed are not part of a normal DSC distress message. The time of fix IS part of the message.

[Copinsay]

Hi all

Out of interest - can someone tell me please what DSC data is sent when making a routine traffic call to the coastguard?

I ask because as there is no signal at one of the slipways I use, I have to call in when 500m out at sea, or at the top of the hill in the car, and wondered if that would be apparent / confusing to the CG?

Steve

[Channel Ribs]

Originally Posted by Poly

Course and speed are not part of a normal DSC distress message. The time of fix IS part of the message.

Thank Pol, do you have a reference for that? I have had this discussion a few times.

[Poly]

Originally Posted by Channel Ribs

Thank Pol, do you have a reference for that? I have had this discussion a few times.

The definitive source is here: http://hflink.com/selcall/ITU-R%20M-493-11.pdf

Originally Posted by Copinsay

Hi all

Out of interest - can someone tell me please what DSC data is sent when making a routine traffic call to the coastguard?

I ask because as there is no signal at one of the slipways I use, I have to call in when 500m out at sea, or at the top of the hill in the car, and wondered if that would be apparent / confusing to the CG?

Steve

No position information is sent to with a standard call (to the CG or another station). Positions are only sent with either a distress call or responding to a specific "position request" (position poling).

[Channel Ribs]

Originally Posted by Poly

The definitive source is here: http://hflink.com/selcall/ITU-R%20M-493-11.pdf

Cracking stuff, thank you.

So the data that is sent is position and time of position, if neither are available then they are marked as such.

[Copinsay]

Many thanks from me too.

Steve

[ShinyShoe]

Originally Posted by Channel Ribs

You seem to be saying that even if I am right then there is still a reason not to like handheld DSC?

Not at all - nothing to do with being handheld or not. I was questioning the practice of switching off the GPS to conserve battery power, when in my opinion it compromises the functionality at the time it might be most needed, i.e. in a hurry to send a possition as part of a distress message.

Handheld DSC is inherintly sensible as a tool, free from other dependancies like 12V batteries, external antena, external GPS, NMEA cables that are usually just twisted bits of wire, being screwed to the boat and not being able to come with you.

[ShinyShoe]

Originally Posted by Copinsay

Out of interest - can someone tell me please what DSC data is sent when making a routine traffic call to the coastguard?

In case you haven't deciphered it in the official document Poly sent - position is not (routinely) sent with routine calls. If you are communicating

Interesting links:
DSC Map
(No idea why ACRO DEE sent their pos!)

DSC messages
(all routine / non-routine messages on CH70 in the Solent.) Not as busy as you might expect!

I ask because as there is no signal at one of the slipways I use, I have to call in when 500m out at sea, or at the top of the hill in the car, and wondered if that would be apparent / confusing to the CG?

Technically you should not transmit unless on the water. It may not be apparent from the DSC message, but if they really wanted to find you they can use DF on your signal.

Steve[/QUOTE]

[Copinsay]

Thanks for that too...

and I quite agree

<<Technically you should not transmit unless on the water. It may not be apparent from the DSC message, but if they really wanted to find you they can use DF on your signal.>>

This is correct - I'm just taking the view that it's better to call when safely back on land and in coverage, rather than call when still out as sea given the lack of VHF and mobile coverage on the slip.

A bit like riding a horse on a wide empty pavement to reduce danger and avoid holding the traffic up.

Guilty as charged on both but I doubt any sheriff or magistrate would follow that through if it's clearly for safety and not causing a problem in reality

It was actually that point that prompted by query, as I wondered if my position was being flagged up on the road :o)

Cheers

Steve

PS - we did have a vessel doing 45kts on an A road last week - AIS left on when on the trailer (not mine I hasten to add!)

[Channel Ribs]

Originally Posted by Copinsay

This is correct - I'm just taking the view that it's better to call when safely back on land and in coverage, rather than call when still out as sea given the lack of VHF and mobile coverage on the slip.

I am put in mind of the old saying "tis better to be judged by twelve than carried by six".

Also I believe you cannot be prosecuted for doing something that keeps you safe, and remaining in contact with the costies does do that.

[Copinsay]

[Poly]

Originally Posted by Channel Ribs

Also I believe you cannot be prosecuted for doing something that keeps you safe, and remaining in contact with the costies does do that.

I'm not sure that is actually true but in the part of the world where Copinsay is nobody would prosecute for a practical and common sense approach. The official answer is likely to encourage you to use the telephone once on shore. In Copinsay's case the likelihood is that if his slipway is out of range of any transmitter then 500m up the road isn't in range of two required to fix a position!

I nearly used the VHF to call the coasties from the side of the road once: I had a puncture on the car, I was already running late, and then discovered that the wheel brace in the car didn't fit the wheel nuts on the car! My mobile was dead (it had been for a swim), and I had a long walk to the nearest phone box. I figured it would be better to break the rules and avoid my wife reporting me overdue and the resulting search. In the end a good Samaritan stopped and lent me a phone...

[Channel Ribs]

Originally Posted by Poly

I'm not sure that is actually true

Neither am I, but I also vaguely recall it has a specific name. Where is Avocet when we need him?

[Jizm]

I have an entel ht640. No probs in 5 years and submersible.

[gotchiguy]

Well this has all got jolly exciting..

Originally Posted by Poly

Notwithstanding wavelength's very good point about why an early departure from a boat on fire might be wise, even a small fire has the potential to wipe out all your on board electrics. Might I ask why you have have a DSC handheld if you always plan to be on board the boat with a working radio and a PLB on your person as a backup if you go for a swim?

Well I don't even have a working fixed VHF anyway so the HX851 is my only radio

Fire is the only time I would consider "abandoning ship" if you like. It is my belief that there is no other circumstance when it is safer to be away from the boat than "on" it. If it capsizes, it will float. If all the tubes burst and the hull is raked with machine gun fire, it will still float.

If the engine sets itself on fire (the most likely place on the boat to cause ignition?) then it has to heat the transom and fibreglass to around 350deg Celcius for the resin to reach its flash point. Although the engine will already be burning at this temperature, it will take a few minutes to heat the transom I think. The battery (soon to be -ies) and radio are fitted to the console, totally isolated if you like, from the fire. They could be used to send a distress message quite easily, certainly enough time to fire a 25W DSC message.

Before abandoning ship, unlike in an aircraft, I think it is worthwhile at least attempting to tackle the fire because it can be kept quite easily to an isolated area. If the engine catches light and is then put out, fine we have no power but at least we are out of the water, potentially still with a 25W radio set.

Anyway this is all academic, I have no working radio, so there's no point either trying to fight the fire or stay on board long enough to use it.

HX851 + PLB is the way forward

[Copinsay]

<< If all the tubes burst and the hull is raked with machine gun fire, it will still float.>>


Wow - I didn't realise things had got that bad in England since I moved to Orkney... good you have thought these things through though.

Steve

[SPR]

It spending to much time in the CH. Islands and Martini's Gun boats running about!