New Bases

[Korpen]

Looking to expand my network of naval bases, and it would be interesting to get some feedback.

Feel that there is a need of naval base on the west side of the Gaelic territories, either on the western isles or in the inner islands. The rate of construction is expected to be low.

Bàgh a' Chaisteil / Eilean Bharraigh
Advantage: The most westernmost alternative, offers the best ability to provide protection for trade in the Atlantic. Relatively easy to fortify, impossible to launch an unopposed attack or landing against the base.

Disadvantage: Far from help and the comforts of civilisation. Limited size of anchorage. Potentially vulnerable to bombardment (can be solved by doing a "Muskö"). No room for errors of defence.

Summery: Very strong candidate, would require a very large amphibious force to knock out.

Port Rìgh / Eilean Sgitheanach
Advantage: On the northern side of Eilean Sgitheanach, well protected from attack as well as bad weather.

Disadvantage: On the northern side of Eilean Sgitheanach, offering little new capabilities for the marine.

Summery: Perceived as the weakest candidate from a naval perspective. However if plans go ahead to fortify Sgitheanach in it entirety to be used a refuge for the population of the western areas in case of UNK attack it offer a good position from were supplies could be moved to the island. 

Bracadale / Eilean Sgitheanach
Advantage: Central position in the isles. Well protected inlet. Hard to bombard.

Disadvantage: Close to the Tallisker distillery. Somewhat exposed to western storms.

Summery: One of the two strongest candidates. Drawback that the island can be attacked from the landward side. So only a real candidate if combined with a general fortifying of Sgitheanach. The coastline of Sgitheanach generally consists of sheer cliffs, so the number of potential landing spots is very limited.

Steòrnabhagh / Eilean Leòdhais
Advantage: Largest existing settlement in the western isles, greatest prospects of stimulating  civilian growth, and future infrastructure constructions. Far from potential hostile bases.

Disadvantage: When it comes to provide support for protecting the isles it does not offer much improvement to the small base at loch ewe.  Limited ability to support commerce protection in the Atlantic. Limited ability to provide a good base for rescue vessels.

Summery: While not a bad spot, I do not feel it offer enough of an improvement to motivate the cost.

[P3D]

Barra. Have direct exit to the West (fast) and the East (in case of baad weather). Castlebay itself is even more protected but only 1km2. The exit can be narrowed for additional wind and wavebreaks.
You have 3-4km2 of possible anchorage which should be enough for anything after building a few moles. Possible problem is the 4m+ tide.

What about THIS?

[The Rock Doctor]

Depends on your priority.  Barra offers the reach into the Atlantic that the other sites lack, but is probably least useful for more basic patrol work around the islands themselves.

How about Lochboisdale on South Uist?  Not quite as isolated as Barra and apparently a nice, enclosed inlet...

[Guinness]

This is likely a question born out of ignorance of the strategic situation on OTL Great Britain, but...

If I were you, and I was worried about the UNK making a push north, I'd be worried more about the mainland, even the mainland coast, and not about putting bases on the Outer Hebrides.

If the UNK were to make a move on the Outer Hebrides, presumably you could easily cut them off and bleed them there with your mines and light forces. The UNK would have a very difficult time supplying them there, I'd think. If you want to be able to defend them relatively easily, I'd concentrate on a base on the Isle of Skye (if you don't already have one).

In other words, don't fortify the Outer Hebrides too strongly, as I'd think in the event of war with the UNK, you'd want them to try to put an amphibious force there. It really wouldn't be earning them much.

All that said, I second Rocky's suggestion.