I get something similar -quick math says a rake of 4 degrees on a 43 foot mast with 6 feet of bury would move my CoE forward about 1.3 feet. 

So tempting.  Colin is right - I could keep that hatch with a forward rake.  Just barely.

I"m reluctant to add that design complication into the rig, though.  It feels like I'm outside my experimental comfort zone just going to the split rig.  Heck, the whole conversion is a bit audacious for a lubber with no offshore experience.  

I guess it's that I feel confident that I can move mast steps and replace hatches.  I don't feel confident that I can understand and develop a well balanced, safe, reliable, and effective raked split rig.  If I was doing some coastal cruising on an easily modified boat, I might enjoy the experiment: it could be very fruitful.  But... maybe not on this one.  Perhaps Slieve will chime in and advise the rake, though from talking to him, I believe that he's not a big fan of the idea.

Hmm.  Chris, how much do you estimate canting the mast with that sail plan moved its CoA forward? 

I thought about raking the mast forward, too, but had to let it go for the reasons Chris mentions.  A thought experiment says that there may be a trade here, though -  a forward-raked split rig would have longer jiblets in the lower panels, tapering to none in the upper where I would un-split them anyway.  Of course, that adds considerable construction complication, and I suspect that by the third panel, the jiblets would be too short to perform their function;   Slieve's geneisis for creating the split rig is that the first third of the airfoil generates most of the windward lift, it wouldn't make sense to reduce those much. 

So, yup, the hatch has to go.

Consequently, I'm toying with two ideas for re-arrangement up there.  Both are in the rocking chair and beer phase of development:

1) Expand the coach roof forward a bit (work!?), and add a new hatch up there?  Roger Taylor's description of trying to get to the foredeck of Mingming by squeezing and squirming past the junk rig's athwartship obstacles sure makes me want a secret passage to the pulpit.  If I don't expand the coach roof, then whatever hatch I add will need some serious offshore coamings - I don't want it flush with the main deck.

2) Since the mast is now eating up the v-berth, why not rig up the chain locker near its step, moving the ground tackle weight aft to offset the mast weight moving forward?  That makes for a complicated areaall around the mast partners and step, but worth the consideration, perhaps?  That leads to questions for a trash pump at the bottom of the locker because now it'll be below the waterline.  Am I getting simpler or more complicated?

On the rig front, I followed Slieve's recommendation and made a model of the rig last night out of string and a few dowels that were kicking around the house.  I haven't fitted it with a mast, yard hauling parrel, or this mysterious peaking parrel yet - just hung from the ceiling by the halyard and snugged with a downhaul.  It's surprising how minor changes in the downhaul and halyard positions and tension change the entire rig shape.   When I get the other elements in there, I expect it to robust up a bit.  Pictures to follow. 

Hi Scott,

"It's clear that I'm going to lose that forward hatch to the mast relocation -  do most people relocate the hatch further forward?  It seems for safety and ventilation at least, there should be some way out up there."

I'm not so sure about your conclusion.  Have your thought about canting the mast forward.  Doing that in this case it could achieve your goals for safety, ventilation, (and limited changes in the boat) and could still place the masthead just where it is located on the sail plan.  The sail would still hang in the place shown on the drawing.  Then, if the mast step were located at the junction of the keel and the forefoot the mast, the mast would pierce the cabin top well aft of the forward hatch.  You would have to change the direction of swing on the door to the head.

Colin

It's really good that you are going to design and build a split-junk rig for offshore work.  The rig appeals to a lot of those converting, because it often requires fewer drastic alterations to the accommodation.  Unfortunately, we have no decent accounts of how it works for long-term, offshore cruising, (ie the usual 10,000 miles a year that voyagers knock up).  I, for one, will be following your story with great interest.  If you could take lots of photos while you are building and sorting out the rig, with a view to writing it up for the magazine somewhere down the line, this would prove to be a great asset for others interested in split junk rig.

Slieve's concepts are one of the more radical variations on the junk rig theme: it would be great to see more of them being built and seriously sailed.