Thanks for your questions, I will do the best I can to answer them.
Basic Tracker is £18.99
Add £10 for the listening device (bug) option
Add £10 for a 12V Power Supply option
Add £6 if you want me to supply a Vodafone Sim Card (This will need registering in a mobile phone capable of using the Vodafone network first).
Regarding the actual tracing, that's a tracing company. I suggest FollowUs (http://www.followus.co.uk
), and reading their reference material will help you. You buy a set number of credits, which you use for location traces. Each trace costs 1 credit, with a zoom in on a location for 0.05 credits. Registering a sim card costs 5 credits (only needs doing once). They also charge 1 credit for checking consent (for tracing) every so often.
Here are their current offers (only visible to actual members, so I have pasted that info here)
June Offer: 50 LOCATION CREDITS £14.99 (about 30p a trace)
Top-Up 20 CREDITS £10.00
Top-Up 50 saving of 5.00 on your LOCATION CREDITS £20.00
Bulk Buy Saver - Top-Up 600 saving of 150.00 on your LOCATION CREDITS £175.00
I'm not sure what you mean by this. I am guessing that you are referring to a potting compound to ensure moisture resistance? I'm not sure how it would affect the reception of the tracker (think mobile phones here), but as long as you don't affect the electrical resistance of the tracker, and its not too thick, it should be fine. That said, even a plastic bag tightly sealed should do the trick.
Regarding range, again, think mobile phones. It is basically a heavilly modified mobile phone, so if you have reception for a vodafone mobile in a given part of the boat, then the tracker will be fine. Things such as RF or microwave radiation will probably affect range.
I have not been able to test battery life properly, and it heavily depends on the batteries used. Normal current consumption is between 5mA and 50mA, 200mA at peak when first turned on. Obviously a higher current rating for the listening device. I have heard of anywhere between 1-3 weeks for them though.
The power supply for the trackers is a regulated 4.4V supply, which can accept an input voltage of 6V to 14V. I'm not sure if it can handle up to 24V without modification. I will need to do some calculations if you require it to handle 24V, as it will most likely need modification (due to heat disipation for the power regulator). Unless you already have a step down transformer to supply an input voltage of 6V to 14V. If there is a demand (2-3 people) for a 24V version, I will happily consider designing a 24V input supply, but it will probably be about £2-4 more expensive (compared to the 12V version) due to heat sinking and suitable casing. Eitherway, I will investigate it for you.
I hope that this helps! Any more questions, fire them my way. I'll put these questions up on my site too (eventually).