B27 = Bristol 27?
If its this
And deck stepped, you'll have to drop the mast forward (instead of aft)...
yep is the only way I'd suggest doing it not "in place," as you suggest.
I'd do it backed into a slip, or better with space across the slip from you to drop it.
An A-frame and lowering tackle (5:1 preferred or better)... You may be able to use the boom as a gin pole though (not sure where you'd attach the mainsheet or whatnot for it though)... You'll want a mast crutch to drop the mast forward into.
This just swap fore/aft... Might be able to build a mast crutch and place it on the dock (again if there is room directly across from you).
Really appreciate the insight and great photos! Is there a reason you drop the mast aft rather than fore? We could easily back ours into our slip todo the work.
My big concern would be the marina not allow us to do repairs, and not dropping the mast would mean we could do it without being too "obvious". The flip side of things, dropping the mast means we'd probably have a better understanding of the state of the mast and the state of of the mast step.
Here are a few photos that I have of the boat.
Overall our bristol 27 is in very clean condition. The exterior wood is in need of sanding and refinishing, it currently is powered by a 15hp mercury outboard hung on the transom as the inboard perkins diesel is in a state of "unknown". The topsides need a new coat of paint, however the bottom was repainted last year with the zincs(including prop zinc) replaced. The owner also replaced all running rigging in 2014 as well.
My priorities currently are as follow:
1. Get standing rigging/chainplates replaced ASAP and any issues on mast/rigging resolved and documented
2. Clean bilge out, seems who ever worked on the diesel got some oil inside the bilge
3. Clean out aft and cockpit lockers - aft locker is where the PO stored fuel tank and all oil to mix in fuel along with stabilizers and random crap
4. Sand, repaint top deck & all wood on exterior + buff top deck - this includes making more holes in the toe rail for water drainage
5. Sand refinish interior wood(not required but would be nice to have that "new" feel)
6. Remake mainsail cover
7. Clean interior, and measure all cushions and start production on new cushions for interior and cockpit(my significant other and her mom are excellent sowers)
While I am working on #1, #2, #3, the SO will be working on #6, #7. Once these are complete we will be working together on #4, #5.