DynDNS and the related services DO NOT GIVE YOU A VIRTUAL DEDICATED IP ADDRESS. They give you a dedicated URL (xxxx.dyndns.org) or something similar that points to whatever IP address your router or device is at. The router or device MUST SUPPORT DYNDNS addressing. However, it won't work if you're behind a firewall or router at the marina.
The main advantage of using DYNDNS is for people who want to host a server at home or their office but do not pay the extra charge most ISPs levy for a dedicated IP address. So they are on a dynamic address that may change periodically, but using the DYNDNS service via their router, they can get to their server regardless of how the ISP has changed their IP address.
IP Addresses, currently using IP V4, are very finite, and limited to a format of w.x.y.z, where each is a number between 0-255. However some numbers and subnets are restricted in their use.
For instance, any IP address that starts with a 192.168.x.y is a "private" address space network and generally behind a router or a firewall. In the case of such an address, the subnet would be 192.168.x, the network address would be 192.168.x.0 and the broadcast address would be 192.168.x.255. The gateway address, usually the router or firewall, would often be located at 192.168.x.1, and the network would support up to 253 devices (256-3 (network, gateway and broadcast)). This would be considered a class C subnet.
The marina's internet set-up does not allow any inbound requests. I could set it up to send a snapshot every 1 hour instead, but I like getting the fresh update, and the images are only 22K in size.
There is a service called DDNS that will give you a virtual dedicated IP address, by the way. It just won't work at the marina. I do have a Plan B. If it works, you will be able to connect to the webcam, pan/tilt, and check out the interior of the boat.
Good idea on the droid not needing wifi. I have something that I'm building for the Droid, not ready to talk about it yet though. Still have a bunch of work to do on it.