Thanks, Wouter and Robi.

It looks like the DH in Robi's diagram is only 4:1?

Although easier to rig there is something very clean and uncluttered about an internal DH system.

Having the DH blocks catch on the boom is a nuissance so eliminating that possibility is worth the trouble. When I've built a similar system in the past, replacing the single blocks with a double block wasn't ideal since it changed the lead angles and the lines didn't feed perfectly into the blocks and had more friction as a result.

Are the blocks on eiter side of the sail's DH grommet pinned there or do they hang on a connector line?

So is it possible to get a 12:1 or 16:1 system like this that works properly without the intermediate blocks catching on things?

Jerry