The cheapest and one of the best chartplotters around is a $200 quad core tablet with a GPS chip in it combined with the $20 Navionics download.
Keep it below decks until they come out with waterproof tablets ( I believe Samsung has one now.) and get the navigator to call the shots to the helmsman.
That worked for us crossing the Wide Bay Bar at midnight on a dead low tide. I doubt I will ever do that again and I do not recommend it. We were lucky.
With the rapid advances in technology and consumer demand I am sure us sailors will soon have all of our electronic navigation aids networked via blue tooth or WiFi so that if one unit fails we do not lose the whole system. I believe the technology has already been developed and not being presented until they have sold off the currently available but already outdated hardware.
Go over to "Shooting the Breeze" section of the forum and look at this thread.
www.seabreeze.com.au/forums/General-Discussion/Chat/DJI-Phantom-3-any-thoughts/These are another toy but because they have a mass market the ultimate in hardware and software is being applied to them. As it has always been, put the word "Marine" in front of anything and the retailers charge multiple times the normal price for the same thing.
Navionics seems to be the only outfit to have responded to our needs by putting out their charting system at a reasonable price. We as tax payers have already paid for the surveying by the Australian Hydrographic Service.
I reckon we should organise a demonstration march in front Parliament House Canberra for "Sailor's Rights".