It sounds like your receivers are getting confused when you move them between your house and your boat. You should disconnect the 105 LNBF at the house also, so that the receiver only finds 119 and 110 at either location. Then as Iceberg said, a Check Switch after the re-install should work.
However, when on the boat, I could still see issues as line of sight is lost when the boat moves.
DishPro (DP) and DishProPlus (DPP)...
If you do not plan on other programming that would require you to receive signals from other than 119 & 110, such as High Definition programming from 129 or 61.5, international programming on various satellites, then a regular Dish 500 should work. But then the LNBF would depend on:
- DP Twin would allow you to feed 1 dual tuner receiver with 2 cables.
- DP Twin could feed a DP34 which could feed 2 dual tuner receivers each with 2 cables.
- DPP Twin (without a DP34) could feed 2 dual tuner receivers, each using 1 cable; but each receiver would need a DPP Separator to feed both tuners.
On the cost effective side, you could just get a Dish 500 with a Y bracket, buy 1 DP Dual/Single LNBF, and then use the DP Dual/Single from the SD-105 and feed the DP-34.
Scott posted some info from the Dish Network Team Summit awhile back, that you may be interested in. It looks like Dish's plan is to have 2 satellites up in December that will allow an 18" dish to point to a single location and pick up all of the programming, including high definition. So you may want to wait and see what they come out with later in the year.