YAPP idea - MOB alert system

[Andrew G]

I mostly sail single handed and make sure I stay on board. I do have a line at the transom to unlock and lower the swim ladder (at >1 m above the water I can't climb on board otherwise).
If Angus is able to include a contact opening on alarm (as well as the proposed 12V contact closure) then one could use his Autopilot Remote YAPP (slightly reprogrammed and with a small hardware modification) on a Raymarine SeaTalk system to:
- kill the engine (via the 12V relay) {no good for me as I only have a manual pull stop}
- set the AP to Windvane mode
- test what angle the (true) wind is at and then turn head to wind (or possibly say 20 deg off) the right way {mine does not have an anti-gybe function}
- set an MoB alarm - this only sets the waypoint (999) and tells you which way to steer (etc) it does not (on mine) automatically steer there (at least this tells whoever slavages your boat that you went MoB).
- . . .

BUT before setting out on this approach "someone" has to decide if this is really what you want. What if it happens in a confined space with hazards or others around? What if it false alarms?
If you have an option to turn it off you can bet your life it will be off when you need it.

I have been thinking:
- kill the motor (as above)
- free the sheets (somehow)

I'm happy to have Angus' proposed YAPP and use it when 2+ up - and continue staying on board.
Cheers, Andrew

 

[ean_p]

Hi Angus
I too would be in the line to purchase a 4 + 1 set as and when you have it finalised please!

 

[VicMallows]

BUT before setting out on this approach "someone" has to decide if this is really what you want. What if it happens in a confined space with hazards or others around? What if it false alarms?

As another single-hander, exactly the same thought occurred to me. I would want an alarm (which could be canceled by a button if all is actually well) with a secondary output after (an adjustable) delay which would then stop the engine/disengage autopilot/etc. Nice if this could be incorporated easily, but trivial to achieve externally from the NO relay output in any case.

Angus: yes, please add me to the list of interested people.

 

[nigelmercier]

^ Perhaps a jumper, or a software option, to configure a 1 minute delay in the relay? Someone asked if the relay could be N/C instead of N/O. I would imagine it is (or could be) a C/O with both.

 

[AngusMcDoon]

^ Perhaps a jumper, or a software option, to configure a 1 minute delay in the relay? Someone asked if the relay could be N/C instead of N/O. I would imagine it is (or could be) a C/O with both.

These suggested new features won't be in version 1 otherwise feature creep will mean it will never see the light of day. The output that is switched on an alarm is not a relay - it is a power MOSFET protected by a 2.5 Amp resettable fuse. It could be changed from normally open to normally closed in software and have a menu setting for this, but as I say, not version 1. To add these extra features in software and their corresponding settings will require the next processor size up. That is pin compatible so can go straight into the board, but costs another £1. I usually solder the processors into place. I could make it socketed so people could upgrade at a later date, but that again will add to the cost.

Prices are looking like this at the moment:

Victim unit

Bare PCB, no components: £2
Assembled device, no enclosure, no batteries (2 x AAA): £9
Assembled device, with enclosure, no batteries (2 x AAA): £11


Central box - lots of options:

Bare PCB, no components: £3
Assembled basic device no NMEA, Seatalk or external alarm output, no enclosure: £20
Enclosure supplied that you cut and drill yourself: +£3
3D printed custom lid to enclosure, no drilling/cutting required (but you still need the enclosure above): +£7
Alarm switched power output feature: +£1
NMEA-0183 GPS input: +£3
Seatalk GPS input, MOB alarm output: £+4

P&P at cost, estimate £4.

So a the full system with every option would be 4 victim units, receiver+enclosure+lid+switched output+NMEA+Seatalk+P&Pat £87, excluding 8 x AAA batteries, but less with less options.

 

[nigelmercier]

These suggested new features won't be in version 1 otherwise feature creep will mean it will never see the light of day. ...

Apologies, I understand the problem all too well

 

[Pagetslady]

The system as designed at the moment has a 12 Volt 2.5 Amp output which is switched on when an alarm is raised. I expect you could use that to stop the engine if you have a stop solenoid. As for turning into the wind - that's not in the current design. However, as I have the option of Seatalk output it would be a software change to do that, assuming you had a Seatalk controlled autopilot.[/QUOTE
Thanks for that Angus I do have all Seatalk on board so I should think you could sort that out, I see that the opinion of most sailors is its best to stay on board, which is of course the best answer, but if you should go overboard and it was possible to stop the engine if motoring and if sailing to stop the boat by heading into the wind would be far better than watching the boat disappear over the horizon. any I would like to place an order for the present model please then I can PM you regarding the next version. How would you like the cash. I assume that the feed to the alarm would operate a relay which could then connect to the stop button.
regards Mike.

 

[AngusMcDoon]

I would like to place an order for the present model please then I can PM you regarding the next version.

Don't hold your breath. It's still only a twinkle on my laptop screen. Orders for the first round of printed circuit boards have gone off to the factory. There's bound to be some mistake, so that will need to be corrected and then ordered again. I am also still swearing loudly at Sketchup trying to do the 3D modelling of the lid.

 

[JohnGC]

Don't hold your breath. It's still only a twinkle on my laptop screen. Orders for the first round of printed circuit boards has gone off to the factory. There's bound to be some mistake, so that will need to be corrected and then ordered again. I am also still swearing loudly at Sketchup trying to do the 3D modelling of the lid.

If it's simple and you have a sketch, I'll do it in my 3D CAD package if you like.

 

[AngusMcDoon]

If it's simple and you have a sketch, I'll do it in my 3D CAD package if you like.

I think it's almost done now. I need to check the position of the holes against the LCD drawing.

Thanks for the offer though. It's been a bit painful, but is a useful skill to have. I struggled with the 4 corner holes which are countersunk on the top and recessed on the bottom.

 

[JohnGC]

I think it's almost done now. I need to check the position of the holes against the LCD drawing.

It looks good. I haven't used Sketch-up but all 3D packages seem to have quite a steep learning curve.

Is a 3D model available for the display and will Sketch-up import it? If so it is a good way to be sure everything fits. My PCB CAD is also 3D capable, it really takes the trial and error out of PCB to enclosure fit and connector pin to holes

 

[AngusMcDoon]

It looks good. I haven't used Sketch-up but all 3D packages seem to have quite a steep learning curve.

Is a 3D model available for the display and will Sketch-up import it? If so it is a good way to be sure everything fits. My PCB CAD is also 3D capable, it really takes the trial and error out of PCB to enclosure fit and connector pin to holes

I'm not sure. I will have a Goggle. I think that a DesignSpark PCB layout can be sucked into Sketchup.

 

[Rum Run]

I'll go for a base + 4 units, just in case anyone ever dares sail with me.
For use single-handing I suspect everyone will have their own idea of what they want the unit to do, and it will depend on the boat anyway. Having a single output for an alarm or what-have-you will allow us to trigger electro-mechanical devices according to taste: currently I am thinking engine-stop (by adding a N/O solenoid valve possibly) and maybe horseshoe buoy release. I assume that if I do fall off it will be in light weather and not attached to the boat, as when it kicks up I will be attached anyway.

Looking at CAD for the lid, I think the features could be machined into the lid using an over-hand router and simple jig (not the lettering). I am no fan of 3D printed objects for anything intended to last more than a few months, as it is not so stable in varying temperature and moisture situations. There is a lot of hype in the RP industry, though no doubt it will all come true eventually.

Anyroad; nice project!

cheers
Rum Run

 

[pcatterall]

Wonderful!! Please may I may I apply for 1+4 crew, great stuff

 

[Bi111ion]

Angus, I was thinking, a plugin to OpenCPN to drop a MOB marker when the alert goes off. I did a quick test on OpenCNP on Navigatrixsend in Shift+Space using the X11 TEST method (xdotool and xsendkey.c) but so far not working. I think a plugin would be be the right way to do it anyway. Any thoughts?

 

[Graham_Wright]

I think it's almost done now. I need to check the position of the holes against the LCD drawing.

Hi Angus. Be aware that, if you intend to have this lid machined, square (i.e. zero radius) holes are expensive. As you have drawn it, it could be CNC machined relatively easily. I imagine that the production run would rule out injection moulding or lost wax casting.

 

[AngusMcDoon]

Hi Angus. Be aware that, if you intend to have this lid machined, square (i.e. zero radius) holes are expensive. As you have drawn it, it could be CNC machined relatively easily. I imagine that the production run would rule out injection moulding or lost wax casting.

3D printing works out at £6 a lid. I'd prefer a machined lid as I have to buy it anyway, the plastic is better and the colour matches. A radiused corner rectangle would be fine, but any idea if anyone can machine for that sort of price in small numbers? The lettering could be left off, the corner holes are already there, so it would be 4 countersunk holes, 3 plain holes and the LCD cutout. The only online quotes I have had have a starting price of £600. I could buy a small 3D CNC router for that price and do them myself.

 

[JohnGC]

3D printing works out at £6 a lid. I'd prefer a machined lid as I have to buy it anyway, the plastic is better and the colour matches. A radiused corner rectangle would be fine, but any idea if anyone can machine for that sort of price in small numbers? The lettering could be left off, the corner holes are already there, so it would be 4 countersunk holes, 3 plain holes and the LCD cutout. The only online quotes I have had have a starting price of £600. I could buy a small 3D CNC router for that price and do them myself.

If you're thinking of machining a flat plate then you could also consider NC laser cutting. 2D only but very clean finish and very small internal radi. Lots of different materials can be cut now.

 

[AngusMcDoon]

If you're thinking of machining a flat plate then you could also consider NC laser cutting. 2D only but very clean finish and very small internal radi. Lots of different materials can be cut now.

So no countersinks with that method. I could use pan head machine screws, but not quite as neat. What is it likely to cost?

 

[KellysEye]

>Doing some tests I have found that the range of the radio transceivers I tried is about 25m.

25m is a problem. In bad weather and with big seas breaking over the boat we had an inflatable Danbuoy washed of the rail, you won't believe how fast it disappeared from sight. The same would happen with a MOB. If two handed then then in the time it takes to go below press the GPS MOB button and get back on deck it is likely that the MOB will have disappeared.

I've said before don't plan for a MOB plan for not going overboard. Fit Jackstays and use a harness with a long and short tether, the long one is so you are able to stand at the mast with the short one clipped around the mast. At all other times use the short one. If going on deck in bad weather go on your hands and knees. We always clipped on at night and in bad weather. The only MOB precaution we had was a six to one block and tackle on a halyard permanently rigged when at sea, we practised pulling each other up in full wet weather gear, I've never seen another boat with that. Whether one person can turn the boat around, start the engine and ideally furl the genoa then find the MOB then use the block and tackle is another matter.

If you've read the MOB tests the yachting mags then it's always flat calm with four large males which bears no relation to real life when MOB invariably happen in bad weather, although it's noteworthy there are very few of them, because most boats don't go out in bad weather. Long distance boats have to put up with whatever weather comes along hence the carrying and use of jackstays, harness and tethers is mandatory.