allwent-
I didn't suggest giving up. I thought I made it clear that in my point of view, your approach is seriously flawed, and you are taking a course of action that is going to lower your odds of recovery further every day.
That doesn't mean give it, it means RECONSIDER THE APPROACH and if your numbers add up a different way, sure, keep doing what you are doing. After all, you have key information that none of us have.
But let's assume (rashly) that your boat might be moving at five knots, between
current and windage or possible sailing, combined. Five knots, 24 hours per day, ten days, right? It may have traveled 1000 miles by now, anywhere in (let's be optimistic) a 45 degree cone of movement. That means it could be anyplace at the end of that cone (sector) along a line a thousand miles long! And if you call that too pessimistic and cut the speed in half, it could still be anywhere on a line 500 miles long.
It would take a light aircraft four hours just to fly that line ONCE, four more hours to step up/down a grid ladder just once and make a second pass ten miles over. Now add perhaps two hours each way from a base, and if you can find a light aircraft with a 12-hour endurance, it still can make only two passes in a day. At which point it has to land someplace, and on the next day? The boat may have moved so much that it has to just repeat the last day's work.
Every day that you have delayed, every day that you have concealed the position, whether that was right or wrong doesn't matter. What matters is that the search area keeps expanding geometrically, and that the more you conceal, the more you delay, the exponentially harder any attempt at locating the boat will be.
Perhaps my logic is wrong on that, but as I said, all the professional SAR people say the same thing. Time is of the essence, and you've already burned ten days of that. As your boat gets closer to other islands (optimistic) it also has a higher chance of either wrecking on one, getting run down at night by
shipping (truth be told, the big ships sometimes just don't look out), or being found by a salvor in any case.
Sorry if that's not what you want to hear, but I can't see any way that your approach has been one that is likely to recover your boat. It just increases the odds that someone else will get it, afloat or otherwise.
As to that other question of how a boat loses a rudder...a rudder is "moving
parts below the waterline" and surprisingly fragile. Most still are made with
stainless steel rudder posts and iron armatures, both unsuitable for exposure to
salt water. Protected by a
fiberglass shell, sure, but all it takes is one bump (hobbyhorsing in a storm while on a
mooring or anchored) or one docking/anchoring where the tide unexpectedly ran out, or one bump while being hauled, and the rudder sat on the bottom, and even the best of frp can develop a hairline crack that admits
water. Ten years later, the weakened metal or frp takes a side load from a wave and it is gone.
Other forum members have had the same rude surprise.