Hey, I’m working on a hexcrawl setting for the game (love it, btw), and I want to use Hexographer and Welsh Piper’s sub-hex templates. The problem is, WP assumes a 5-mile sub-hex with 25-mile regional hexes. It’s easy to change the small hexes to 6-mile, but that makes the regional hexes 30-mile.

I assume the 6-mile sub-hex size is more important than the 24-mile regional hex size? Would it run havoc with the math too much to assume a 6/30 sizing instead of 6/24? (5/25 would pretty much keep the upper scale true, but that seems less important, I think)

For what it’s worth, I’m using ACKs 24-mile/6-mile hexes with Red Tide’s 25-mile/5-mile hexes , and I just ignore the difference. I guess that means the island is a bit larger (smaller?) than cannon, but who’s going to notice?

No problems with changing the ratio then? I wasn’t too worried about the size of the hex not being exactly the same, as long as it’s close, I just wasn’t sure if the 4-1 ratio is necessary.

Yeah, 6 mile hex is the way to go, though I was pretty pre-disposed to that already. The 30-mile regional hex shouldn’t give too much grief, I wouldn’t think.

The main effect of changing the hex size is that you change the amount of territory that a domain of a particular hex size controls.

Here are the sizes in square miles of the various hexes:

5 mile hex: area of 22 square miles

6 mile hex: area of 31 square miles

24 mile hex: area of 500 square miles

30 mile hex: area of 775 square miles

First Implication: A wilderness domain cannot exceed 4 families per square mile. A borderlands domain cannot exceed 8 families per square mile. And a civilized domain cannot exceed 25 families per square mile. So with 5 mile hexes you will have maximum families/hex of 88, 176, and 550 respectively.

Second Implication: A domain's maximum size is one 24 mile hex. Large domains must be divided and assigned to vassals to create realms. Therefore, if you increase the size of the hex from 24 miles to 30 miles, you are increasing the maximum size of domains from 12,500 families to 18,750 families, which is an increase in the direct power of a lord of about 50%.

Interesting. Thanks Alex, having only read the book, I thought there would be implications to changing it up, but I wasn’t sure exactly where. I think I’ll just build the sub-hex map with 30 mi. hexes and but set the regional map to 24 mi.

I'm new to ACKS (the nostalgia! yes I played B/X for years back in the day...) and I've found all sorts of things to be excited about.

One of those things is the Domains & Strongholds rules - I like the concept, I think tying experienced characters more closely to the world is a great idea (in 5e I'm in a party of level 19 Armed Hobos...) and the fact that it's obvious where low-level characters can go for training is really nice.

But...

I can't fit 16 6-mile hexes into a 24-mile hex, at which point my brain struggles to make sense of the math.

If I take some 6-mile hexes and try to build a larger hex, I can easily build a hex 18 miles across with 7 6-mile hexes and I can easily build a hex 30 miles across with 19 6-mile hexes.
The 18-mile hex has a diagonal 3 6-mile hexes long and edges 2 6-mile hexes long
The 30-mile hex has a diagonal 5 6-mile hexes long and edges 3 6-mile hexes long.

The 24-mile hex falls in the middle of these. The best I've been able to work out is that the 24-mile hex has an area 12 times that of a 6-mile hex and the best layout I could get covered 7 full 6-mile hexes and parts of 12 other 6-mile hexes (6 @ 1/2 hex and 6 @ 1/3 hex). And yes, I looked at a hex map to check this all out.
And yet, the rules use a factor of 16 going between 6-mile and 24-mile hexes - ???

So, not only am I confused by using 16 instead of 12, my 24-mile hex map could have a 6-mile hex straddling the corner/edge of 2-3 24-mile hexes, meaning that where things are sited in the 6-mile hex gets really important.

Did I miss something? Is there an extra factor involved that I'm not taking into account?

I am curious what the rationale was and what other people think about this - I'm hoping to start an ACKS campaign soon and I could use the clarity.
My current inclination is to use all the values given for 6-mile hexes, use 30-mile hexes for scaling up (and 1.2-mile hexes for scaling down, same reasons) and redo the math to create new tables - but I'm not certain that is the best choice to make

Take a look at the blank hex map at http://www.autarch.co/system/files/files/ACKS_BlankHexMaps_0.pdf, and you'll see that each large hex contains 13 intact hexes and 6 half-hexes - which is to say, each large hex contains 16 smaller hexes worth of surface area. Each of the larger hexes is four smaller hexes across (or rather, three whole hexes and two half-hexes), so if the smaller hexes are each 6 miles across (measuring from any side to the opposite side), then each of the larger hexes must be 24 miles across.

...it took me a while to work out what I had been doing wrong. I think I started thinking the hex was 24 miles corner-to-corner instead of side-to-side; I did actually consult a hex map but didn't manage to look at it correctly, apparently. Taking another look at http://steamtunnel.blogspot.com/2009/12/in-praise-of-6-mile-hex.html also helped; while I didn't get it immediately, the picture showing what distance across the hex was 6 miles and what was 7 miles eventually helped me realise what I had been misunderstanding.

Ah, you were assuming that distances were being given for the side length of each hex, rather than for the width of each hex? I'm told that's a common misunderstanding.

To avoid it, I usually tell my players "it's six miles from the centre of one hex to the centre of any adjacent hex."