I really like your ideas and with the challenge you are trying to resolve I can see how money
would be an issue. I have absolutely no doubt you would be able to build a cheaper system as you have planned but I do see a few possible challenges:
- You will need everything on the boats to be able to handle the lifeguard rescue marine environment
which I imagine is not all 'plain-sailing'.
- It would have taken a bit of technical fiddling so fails the KISS principle and could have issues when you least expect it. In life and death rescue situations, can you really afford for this to happen.
- It may have a higher ongoing operational cost eg 10 x Data SIMs either prepaid with ongoing topups or on contract
- It will be limited by mobile coverage.
I agree with Jim Cate, this sounds exactly what AIS was designed for so I would suggest a pure VHF
generally has better coverage than mobile but clearly subject to location of your 'home base'and the terrain / coverage of the 25sq mi you cover.
- Will not only allow the base to see all boats and all of the boats to see each other but also other vessels with AIS can see / be seen!
- Will plug
into any NMEA
network any of the boats already have and allow easy future NMEA expansion.
- Keeps the solution simple and robust with lower ongoing costs BUT will have a higher set up cost
I would suggest the Vesper Marine
Waterproof - designed for marine environment
/ USB - allows for wireless or wired connection for data to be pushed to a desktop
, smartphone or tablet which you can put an app (OpenCPN or other) on to display the data. You can connect up to 5 wireless devices without needing a seperate router.
and 2000 - allows data from other NMEA sensors to be shared as well and will also allow AIS data to be shown on NMEA attached MFDs (assuming your bigger boats have these?)
GPS Receiver - with internal antenna
but usually comes with external as well.
VHF Receiver - can have own external VHF antenna
or add splitter to use existing VHF radio
Now clearly at around £540 a piece without power supply connection, splitter etc this is likely to be outside your budget
but a couple of thoughts on this:
- you should consider how long you planned solution is going to last for (3-5 years?) and calculate the SIM Data costs over this lifetime.
- perhaps you could approach Vesper Marine directly to see if you can get at cost or wholesale in return for a written and video case study about the setup for 10 boats and benefits it brings. A life guard case study must be pretty valuable.
- If still not affordable for all boats but you end up with an AIS solution, perhaps you could just install on any bigger boats you have that already have NMEA backbones, an MFDs and VHF antenna.
All the best. I am sure that what-ever solution you end up with will bring a huge benefit over what you have now!