Two questions:
I know that it is legal to move the boom blocks, and I have heard that some people move them. Has anyone found a location that is better? What are the benefits of this move?
What type of blocks should i use in replacement?
Fortunately you have much latitude while still conforming to the rules for Class event participation.I may try to find a different strap to attach them though. My current strap is a very shallow U which causes the block to chafe and damage the boom. Newer booms have straps with a much deeper U, which solves this problem. The trick will be finding straps with holes that are the same distance apart as what I currently have.
Also it is recommended to through bolt these instead of riveting. I may consider doing that.
I don't like the idea of through bolts, although it seems popular. They add weight and worse, a snag point on top of the boom..
. . . how much do you think additional holes weaken the boom?
Another idea that has just crossed my mind is using several very tight wraps of spectra as an attachment point. This would have the advantage of being easily moved to experiment with block location.
Rick, this idea makes so much sense. All round a good idea.
Is it legal? You can use any kind of strap so i assume that it is.
All this discussion has caught me in the middle of checking out my boat for the NA's. Good review for me of the what's, why's and how's of my boat's setup.
I had previously bolted the boom bails (only thru the bottom side of the tube, not the top). After thinking about it a little more, I decided to reverse the situation. I use padeyes on top of the boom and suspend the boom blocks from there. .
a. The padeyes are small, lightweight, low profile (doesn't interfere with the sail), take very little stress, and install with aluminum rivets and 5200.
b. I use an upper spar in place of the lower, so there are NO holes in bottom of my boom (where the greatest tension stress is located). I certaily don't worry about padeyes pulling out. The stress is taken up by the entire boom section. I'm good as long as I inspect and replace the lines when needed. Three years now, lots of use and no line wear.
c. The boom blocks do not apply torsion stress the to tube at all, such as when reaching or downwind.
As to location: Yes, the aft block location DOES make a difference. The effect is similar to a Jens rig, only for the lower aft portion of the sail vice the upper half. I tried the aft boom block much farther forward - about a whole "segment" - forward of the next sail tie. This was about 117".
a. The lower aft portion of the sail "breathed" a little better in blow. The boom (from the boom bail to the aft tip) flexes a little more to leeward in the puffs. Goodness knows, the lower leach of the sail hooks around to weather badly enough.
b. The main flattens out just a little more effectively when the mainsheet is cranked in.
I found this to be a little TOO effective, so I moved the location back some. At 200#, I need all the power I can get. The bail is located in the middle, between sail tie locations with the outhaul at it's fully eased setting. This is about 123".
a. It allows the lower part of the sail the breath a little better than the stock location.
b. It never snags a sail tie with the outhaul in any postion.
c. Not as effective as the 117" position, but a fair compromise.
d. Requires a few less feet of mainsheet length (unimportant).
The forward boom block is too far aft on the stock boat. I sail most frequently with the gooseneck at 14 to 16". The fwd boom block location comes into play when you need to really crank the main in tight - almost touching the boom block to the ratchet block. This is where you don't want to see a strange or radical angle between the blocks. Usually this occurs under heavier wind conditions. My boom block is set at about 62", directly over the ratchet block with the gooseneck set at about 18" (see photo). I rarely set the gooseneck at 20" or more. Under these conditions, I don't find my self cranking in the main so much.
When you link fwd boom block location with gooseneck setting, then everyone's optimum location might be different. I watched Nancy Heffernan (about 110#) at the International Masters get away with a main fully cranked in under winds of about 8 to 10 mph. No way I can do that.
Bottom line: my blocks are located and attached to minimize axial and rotational forces on the boom at the gooseneck. Keep it simple and minimize chances for failure or undesired consequenced.
WD, thanks for the info, this old body needs help ducking, LOL. BTW, when you say 16" on the gooseneck, are you talking from the tip, or just the aluminum section of the spar. Sorry to ask so bacis a question but I need to know. Thanks, Win ever.