On the boom breaking, it was underbuilt from the day it left the drawing board at the manufacturer. No boom should snap under those conditions, regardless of type of main, period. They should have (and did) calculate the stresses on the boom, over time, in conjunction with wear & tear, corrosion, plus different types of mainsail
attachment. Though despite this, they knowingly put an undersized section on the yacht for the simple reason that it was cheaper.
Any competent rigger, of some experience, will tell you as much as well. And likely can do the math behind how strong your boom should have been vs. how strong it was. Ditto on any spar manufacturer..
As to fitting attachments, in this case, the bail. Sometimes when holes are drilled in booms, & definitely in spars, for load bearing bolts & fittings. A hole big enough for a supporting, compression
tube is machined into the boom's side wall. Then an aluminum
tube big enough for the bolt is inserted, & a reinforcing plate is welded onto the boom's wall on each side. Assuming, that is, that the boom's built so lightly (read close to it's calculated @ the factory, failure tolerance) that it's weak enough to need such reinforcement. Which it shouldn't be.
If there's any doubt, look at all of the booms on racing
boats with HUGE, elliptical lightening holes cut into them. And they surely don't run mainsails which are attached along the entire foot of the sail. Plus the guys who race
, & take care of them, attach fittings to their booms, pretty much on whims. I say this given 28yrs of racing
(and boat care, plus limited building) experience. A good bit of it professional, up to the America's Cup & similar levels.
If you want to argue this issue with the insurance company, you'll need the pieces of the boom. Some qualified, Forensic Naval Architecture, & or qualified expert opinion to back you up. In addition to the original design specs for the boom. Also, professional metallurgical analysis of the failure wouldn't hurt. Nor would expert design analysis of the boom's design, & their comments on the boom section's strength & stiffness for it's intended purpose.
Though again, a well qualified rigger could do a lot of this, particularly one with experience in rig design.
As to Forensic Naval Architecture, here are links to a couple of examples:
Four Mast Failures
Forensic Naval Architecture
Also, take a look at his links page.
Realistically, in this case, given the cost of hiring those type of experts, plus attorneys, it may just be cheaper to either; sleeve the boom back together, & reinforce it. Or to pick up a stiffer/stronger section (likely used, & thus very cheap), modify it to your likings. And refinish it to match with LPU.
IE; Number of sheaves for reefing/reefing system design, attachment point style & number, etc.
Knock on wood, even starting with part of a spar section from a smaller vessel, to use as the basis for a custom boom, would work in a pinch.
In terms of attachments, most, if not all, high performance boats simply use short Spectra strops or Loups to attach blocks & other high load items to booms nowadays.
The exception being that depending on the design, a fair number use hard, aluminum "noses" for attaching vangs (or carbon fiber ones, when the boom's made of such).
Plus of course the appropriate reinforcement sections in proximity to the vang's attachment. Which are; riveted, screwed & glued, welded, & or laminated in place.
Or... if you're handy with tools, you could build your own tricked out custom one, out of carbon fiber (S-glass, & Basaltic Fiber), cores, & off the shelf components. Heck, you could even go all out, & build it in the Park Avenue style if such suits your fancy & application ;-)