circuits, the term, "shunt", has two very different meanings which should not be confused:
1. a low-resistance path between two parts
of an electrical
circuit; sometimes known as a "bypass"; and
2. a conductor connected in parallel in one part of an electrical circuit, and designed to pass a known fraction of the current.
In the first case -- which is almost certainly the meaning on your boat -- it is a means of directly connecting two battery banks together (or "BOTH" in the common U.S. marine
In the second case, it is a device used to reduce current/voltage levels in a circuit to a level compatible with metering. Example: in high amperage circuits you don't connect an ammeter directly in the circuit, because the meter isn't designed to handle huge amperage loads. Rather, you employ a "shunt", which passes the high amperage load just fine, but bleeds off a tiny portion to feed the ammeter, which is calibrated to read the total amperage passing through the circuit.
RE: your on-off switches, if you're going to have a single
house bank consisting of T-105s in series/parallel, you only need one load switch, and that on the positive side.
You need another on-off switch for the dedicated engine battery.
You need appropriate fusing as well on the house battery circuit and, optionally but recommended, on the starting battery circuit. High-amperage ANL fuses
and holders are one good way to go.
Don't know how you plan to set up your charging
, but the preferred way these days is to run ALL charging
sources (alternator, wind generator
, solar panels
, battery charger
, etc.) to the HOUSE batteries, and then to use a small device such as an EchoCharge or a DuoCharge to maintain the starting battery (which requires very little charging).