I need to replace the nuts & washers on the keelbolts of my '74 C27. The bolts themselves (mild steel) look fine, just the nuts & washers need replacing. (I lie in fresh water 90% of the time.) "Conventional wisdom", from multiple sources, (as you know, most times, as in this instance, incorrect) said they were 1/2" diameter bolts, 13 threads per inch. But in trying to put a die on the bolts, that size was a little too small, but that's the largest we have in the die kit. Maybe 9/16? 5/8? Hard to tell because of the gunk coating that was put on them. But what TPI? Before I go out and buy another die kit ($$$), anybody have an idea of the size and TPI I should look for?