I have been communicating with Triumph Boats about all the questions concerning the installation of an inner hull drain. Here is the official response:
"All Triumph boats should be supplied with an inner hull drain. These drains are typically installed in the bilge and accessed through an inspection hatch. Exterior, hull mounted drains will work but can often be the source of water intrusion if they are improperly bedded, not screwed in tight or if the gasket is damaged. While these same problems can occur in the bilge, it is much less likely that the drains will be constantly submerged like an exterior mounted drain."
I've attached pictures from the factory of where these are located on each boat model.

170 Models
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190 Bay Models
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195 Model
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215 Models
Here are further instructions from the factory regarding the possibility of inner hull water:
If water is going in, it will typically come back out. If a person is concerned they can:- Check the drains that are located on the sidewalls of the bilge
- (With the boat out of the water) Make sure the bilge is pumped out and relatively dry and watch to see if there is any water coming into the bilge, especially around the center, keel support.
- After the boat has been out of the water long enough for the trailer to drip dry they should look and see if they see water continuing to drip, especially around through hull fittings, transducer and trim tabs screws, motor bolts and drain holes.
NOTE: If you remove these drain plugs to check for inner hull water, be sure to replace them before getting back on the water.