The Incom A-24 Sleuth in Enter the Unknown is listed as silhouette 3, with a length of 20 meters, correct?

Then go to Fly Casual page 55 a look up the WUD-500 Star Yacht, listed as silhouette 4, length of this vehicle? 18,5 meters.

Granted, this isn't a common overlap and one could of course speculate on whether or not this is a typo, I won't.

It does show however, that length in and of itself (and that is the only measurement we have for most ships, mass, width, "bulk" and the rest becomes speculation) isn't necessarily the be all end all of silhouette. It does of course factor in significantly (and would be a deciding factor in the majority of cases), but it also shows that a scout ship may well have a smaller silhouette than a smaller star yacht, to me this shows that design, role and function can affect silhouette. Which only makes sense when you think about it.

Most starfighters and partol boats seem to fit into the silhouette 3 to 4 category, whereas light freighters and transports seem to be covered by silhouette 4 and 5.

Now, of course I'm not saying one should determine silhouette by role or function alone, that's silly, but to say that role and function has nothing to do with silhouette is equally silly. The two are not unrelated, they cannot be as both pertains to the same vessel.

Not in the way you are thinking.

At least not in your humble opinion... or... do you speak the truth?

Well silhouette should be based on size. Because that is what it is. And Length is not the only factor in size.
The Role is related to size only in that certain sizes are appropriate certain roles. But when you are looking at craft and you know what size that craft is. That is what you should use to determine its silhouette. Not the role.

Well, this is where we disagree, somewhat, not too much I think, but when you have overlapping or borderline cases, I think role and function can play a vital part if you're in doubt, like for instance with the Sleuth and WUD-500 above. The Sleuth is bigger, but has a smaller silhouette than the WUD-500. In this case I would think it's safe to assume that the role of a scout craft could be part of why it has a smaller silhouette than the star yacht. The WUD-500 is arguably within the reaches of a silhouette 3 category (it's only 2 meters longer than the HWK-290 - according to FFG/the X-Wing miniatures game, not wookiepedia where it's listed as 29 meters long...) and the Sleuth is easily within the silhouette 4 category, but both are in this borderline area of size, where function and role can be an important factor, I believe. Both could easily be silhouette 3 or 4, but the smaller one got the larger silhouette in this case. Why? Role, design and function I think.

I don't think it is role making that determination but size beyond length. As in width and height and general volume of the craft. Not the role.

Well, you're free to think what you want. Luckily.

I do think role in this case could be a deciding factor. It's an abstract of how the ship works that cannot necessarily be represented detailed enough within the confines of the other stats. Particularly when you look at the higher silhouettes you see that keeping to size isn't always the best or only explanation for why the wayfarer, yz-775, cr90 and other silhouette 5 ships share the same category. Obviously it is mainly size, I'm just proposing to put more (than one) thought into the equation, to juggle as it were, more than one thought at a time.

Silhouette doesn't so much as determine the role of a given vehicle as much it determines the performance. Silhouette 5 and larger have 4 (Forward, Aft, Starboard, Port) Defense Zones while Silhouette 4 and under only have 2 (Forward, Aft). Silhouette also determines the availability of certain maneuvers that can be done. Silhouette 5 and larger cannot perform Gain the Advantage, Stay on Target, or Evasive Maneuvers due to the Silhouette 4 and under limitation.

Well, to get this thread back on the rail, the police gunship should be either silhouette 3 or 4, depending on your preference and how big, bulky, slow, and how large crew and passenger capacity you imagine it to have.

Basing it on the Laat/i could indicate silhouette 4, but as we saw in TCW these are/seem smaller than the Laati/s. How easy should they be to hit for silhouette 1-2 attackers? and how difficult should they be to target for other vehicles (not counting defence like shield or armour)? These things matter too. Being a bulky police transport/mobile command module, with limited handling, I can see it being either, it also comes down as Daeglan argues strongly what exact size you think it has. If it's between the 17 to 22 meters mark, it can be either as far as I'm concerned. Considering that it's also a troop transport (perhaps not 24 officers in riot gear, but perhaps 12?) I wouldn't think silhouette 4 is too big, even if it's 15-17 meters long, 3-4 meters tall and 6-7 meters wide. It would normally be a silhouette 3 I guess, but in this case I'm not certain.