I think I'd prefer having IDA create closer tolerances in the trunk-to-board fitment using the board material itself, mainly for durability and improving the board's ability to accept stresses, and transer them to the hull. A good analogy is in tuning the rig tighter to avoid the shock loading that BWY has experienced. The board cannot avoid, but can minimize those shocks if clearances are closer.
Of course "sizing the trunk" is a big issue. You HOPE that the trunk sides are "almost" parallel, and the fore and aft verticals are too. Finally, it seems to me that the worst form of shock-loading is fore and aft. That's why I liked the board design that's pictured on page one of this thread - it has rollers to serve this function.
You might ask IDA if he can design some Ball-casters into the leading & trailing edges of the upper board. After all, they're designed so support our weight at the bottom of chair legs ....
Keel 180 Lbs
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delevi
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Joel & I did discussed giving the board additional volume to take up some of the slop in that trunk. As it is now, the widest point of the trunk is 1 1/4 " wider than the widest point of the board. Way too much play.I think I'd prefer having IDA create closer tolerances in the trunk-to-board fitment using the board material itself, mainly for durability and improving the board's ability to accept stresses, and transer them to the hull
I like the idea of ball casters. Not sure how difficult this would be to implement and how much more the cost will increase, but it's worth exploring. I am also exploring having a 2:1 or possibly a 4:1 block built into the top portion of the board itself.
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delevi
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Just talked to Joel about the casters; not happening quite complex with the foil shape, and may not fit the trunk right and would be quite costly. Plan B is to put a coating of PVHMC (I think that's what it is) around the top 13" of the board to protect it in the trunk. This layer will be flush with the gelcoat finish of the rest of the board. The board will also have a larger cord length and width to take up more of the trunk. We'll leave about 1/4" of play. Hope we're not cutting it too close. 
The integrated purchase system would be quite complex and costly, so that's out too. I was thinking now to mount the clutch on the port side instead of starboard by adding a second cheek block directly to port of the existing one. I would think that would give me a 2:1 purchase. Joel said that it wouldn't, since there are no moving blocks. Now I'm confused. If you can wrap the outhaul line of the mainsail around the cleat and pull the other way to get a 2:1, why not the same by reversing direction of the load you're pulling on deck, which is what would happen by adding the 2nd block. Anyone?
2-3 weeks until I receive it, then the test flight and hopefully a good report to post here to my Mac friends.
The integrated purchase system would be quite complex and costly, so that's out too. I was thinking now to mount the clutch on the port side instead of starboard by adding a second cheek block directly to port of the existing one. I would think that would give me a 2:1 purchase. Joel said that it wouldn't, since there are no moving blocks. Now I'm confused. If you can wrap the outhaul line of the mainsail around the cleat and pull the other way to get a 2:1, why not the same by reversing direction of the load you're pulling on deck, which is what would happen by adding the 2nd block. Anyone?
2-3 weeks until I receive it, then the test flight and hopefully a good report to post here to my Mac friends.
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Frank C
Leon,
There is a notable benefit to leading the board uphaul along port side, since you must provide a clockwise feed to the winch.
At least feeding to the port winch places your Spinlock clutch perfectly parallel to, and immediately adjacent to the port hatch rail. You've moved the winch-assisted daggerboard line from the mid-starboard deck to the inside edge of the port deck.
I first led my main halyard aft to the cockpit along the port rail for exactly this reason.
I later moved it back to starboard because I found that I rarely winched the halyard.
There is a notable benefit to leading the board uphaul along port side, since you must provide a clockwise feed to the winch.
At least feeding to the port winch places your Spinlock clutch perfectly parallel to, and immediately adjacent to the port hatch rail. You've moved the winch-assisted daggerboard line from the mid-starboard deck to the inside edge of the port deck.
I first led my main halyard aft to the cockpit along the port rail for exactly this reason.
I later moved it back to starboard because I found that I rarely winched the halyard.
With the clew outhaul, the grommet acts as the moving block. For every foot of line you pull forward from the cleat, the line from the eyestrap to the grommet, and the line from the grommet to the cleat, each get shorter by 1/2 foot, so the load (the sail clew) is moving 1/2 of how much you pull the line, with twice the force you're applying to it.
The line you're hauling in is the 1 after the : and, for x:1, you have x lines, each getting shorter by 1/x times the distance you pull the :1 line.
If you want 2:1, you'll need to rig something up that requires hauling in 10 feet of line to lift the board 5 feet.
The line you're hauling in is the 1 after the : and, for x:1, you have x lines, each getting shorter by 1/x times the distance you pull the :1 line.
If you want 2:1, you'll need to rig something up that requires hauling in 10 feet of line to lift the board 5 feet.
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Frank C
Leon,Moe wrote: ... If you want 2:1, you'll need to rig something up that requires hauling in 10 feet of line to lift the board 5 feet.
Amplifying Moe's comment a little more specifically, there is a quick and easy way to create a 2:1 lift for your new daggerboard. (Caveat - I've never looked at a 26M deck or board slot, so all of these dimensions are SWAGs, just for example.) Mapping out your basic 1-to-1 lifting line, from the cockpit forward:
- For basic 1-to-1 Purchase
* you have a ~3-foot tail on your line, lets say aft of the port winch;
* next, the line extends ~5' forward of your Spinlock clutch;
* then it turns 90-right on a deck block, ~2 feet to the reach the board slot;
* finally, 5 feet of line drape over your deck block to fully extend the board;
* so the basic 1:1 line is ~15 feet to fully extend the board with a 5-foot drop.
For 2-to-1 Purchase
* Now, for the extra purchase, instead of attaching the line to the board:
* attach a single block to the board;
* extend the lifting line straight thru this block (this is the "moving block");
* and across the board slot to terminate at a deck padeye just an inch past the slot ...
* since the line must now reach down & back up to the deck, double this segment to 10 feet;
* making the total length of the lifting line now 20 feet;
* so instead of pulling 5 feet of line for a 5-foot lift, you'll pull 10' thru your clutch..
But if you have an inch of space at top of the board, it seems a pretty simple matter for you to just attach a block to the board and gain a 2:1 - even without IDA's help.
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delevi
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Thanks Moe & Frank.
Frank, excellent idea about the block on the board. I think this will be the best solution. The only issue is that the plate and roller which sits on top of the DB slot has just one roller. I would need to get a different piece of hardware made with double rollers to accommodate two lifting lines. There is a hole for the stop line, which I may duplicate i.e. drill a second hole in the plate to attach the top of the lift line which will run through the block. I'll have to go back to the boat and take more measurements.
I was at Arena Yachts yesterday to get some steering problems fixed & adjusted. I had a chat with Jeff about the board and we also did some tests. We put a block of wood on top of a recessed stock db, and I would stand on it, having Jeff winch the line, lifting the board with me on top. I weight 200 lbs. No problems. Then he had me lift him. Although he's only 150 lbs, It didn't take much effort to winch him up. The hardware took it without a problem too.
Jeff was quite animate, however about not changing the dimension of the stock board. I was really hoping to take up some of the slop in the trunk, but he told me that previous DB Macs had less space in the db trunk, but Roger increased it because people would get weeds or twigs stuck in the trunk and the board would jam up. With the extra weight, I would need to get the snorkel gear on to unjam any such problem; not good. I also overestimated the amount of slop by measuring the top of the trunk opening. Jeff pointed out the trunk actually tapers down, so the top of the opening is larger. Keeping the board the same dimensions would also eliminate the possibility of the new one not fitting in the trunk properly, but would not decrease the banging around, due to the large trunk area, except for the fact that the added weight by itself should decrease this. Also the board will be much stronger, with added protection at the top, so hopefully it won't get chewed up like my previous two boards. This is a lot of money for an experiment, but I think playing it safe and listening to someone like Jeff will be the most prudent decision. I'll post my progress when I receive the board and do a test sail. In the meantime, all suggestions are much appreciated.
Frank, excellent idea about the block on the board. I think this will be the best solution. The only issue is that the plate and roller which sits on top of the DB slot has just one roller. I would need to get a different piece of hardware made with double rollers to accommodate two lifting lines. There is a hole for the stop line, which I may duplicate i.e. drill a second hole in the plate to attach the top of the lift line which will run through the block. I'll have to go back to the boat and take more measurements.
I was at Arena Yachts yesterday to get some steering problems fixed & adjusted. I had a chat with Jeff about the board and we also did some tests. We put a block of wood on top of a recessed stock db, and I would stand on it, having Jeff winch the line, lifting the board with me on top. I weight 200 lbs. No problems. Then he had me lift him. Although he's only 150 lbs, It didn't take much effort to winch him up. The hardware took it without a problem too.
Jeff was quite animate, however about not changing the dimension of the stock board. I was really hoping to take up some of the slop in the trunk, but he told me that previous DB Macs had less space in the db trunk, but Roger increased it because people would get weeds or twigs stuck in the trunk and the board would jam up. With the extra weight, I would need to get the snorkel gear on to unjam any such problem; not good. I also overestimated the amount of slop by measuring the top of the trunk opening. Jeff pointed out the trunk actually tapers down, so the top of the opening is larger. Keeping the board the same dimensions would also eliminate the possibility of the new one not fitting in the trunk properly, but would not decrease the banging around, due to the large trunk area, except for the fact that the added weight by itself should decrease this. Also the board will be much stronger, with added protection at the top, so hopefully it won't get chewed up like my previous two boards. This is a lot of money for an experiment, but I think playing it safe and listening to someone like Jeff will be the most prudent decision. I'll post my progress when I receive the board and do a test sail. In the meantime, all suggestions are much appreciated.
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baldbaby2000
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Leon,I have now busted two stock boards. One completely broke and my existing one is quite chewed up.
Do you have photos of the inside of the broken board. I'm preceeding with a "cheap" mod where I'm adding lead shot (probably 75 lbs or so) to the daggerboard. I'm not sure if I'll melt it and pour it in or mix it with epoxy (as suggested by Richard O'brien) and pour that in. In either case I plan on running a stainless steel pipe (maybe 1" od) inside the board (for the whole length) for added strength. There seems to be a support structure inside the board and I'm wondering if that's hollow and if the pipe could go through the center of that. Otherwise I'll put it either fore or aft of the internal support. Thanks.
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Frank C
Leon,delevi wrote: .... excellent idea about the block on the board. I think this will be the best solution. The only issue is that the plate and roller which sits on top of the DB slot has just one roller. I would need to get a different piece of hardware made with double rollers to accommodate two lifting lines.
I just noticed your comment, and the issue is much easier than you described. You will NOT need two pulleys on the existing cover plate, only the existing one. The lifting line can simply dead-end on your cover plate just like the safety line. From its dead-ended point it goes down & thru the board block, then back up and over the plate block, before leading portside and on toward a rope clutch. With ten feet of slack at the board slot, this gives you a 2:1 purchase.
I'm looking forward to reading about your new board & its results.
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delevi
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BB,
Unfortunately, I didnt take any photos of the broken board. I gave it to the dealer to take to the Mac factory to see if they would replace it. They didnt, saying it was my fault. I never saw the broken board again. From what I recall, there is a thick cross section of fiberglass running through the center of the board, sort of like a T. This leaves four cylindrical chambers which are hollow. That should accommodated the pipe idea you are planning on. I would be careful with mods to the existing board, however. I remember the exterior glass being quite thin. It appears that it wouldnt be very strong to hold up the added weight. Also, everyone I talked with, including two boat shops and my dealer cautioned that adding lead to this hollow, thin board would likely result in the board breaking under load. This is why I decided to have a custom one made. If you do proceed with your mod, you will likely find the empty portions in about 1 or more from the corners of the board. Just avoid the center bulk section which is where the solid glass T section is.
Frank,
The M hardware for the DB consists of a steel plate on hinges, flopping over and resting on the deck right over the DB trunk opening. This plate has a built-in roller, going one way to starboard which runs the uphaul line from the Db to the cheek block at starboard and aft. The hole is for the stop line. I went ahead and installed a rope clutch on the starboard side, just forward of the winch. Running it to port didnt seem practical. I did some tests with the dealer, running it to port and the additional block just added more friction and the reverse of the lines rubbed against each other as well. Since there are only 3 in the trunk (73 trunk and 70 board, there wouldnt be much room for a block. Also, there would need to be an additional attachment point, probably a second hole in the plate, which I am reluctant to do, since it may weaken it somewhat. With the tests I did with the dealer, winching 200 lbs was not a problem for me at all. This was done with me standing on a wooden block, placed on top of a stock DB and Jeff winching the board up with me on top, lifting me up. I then lifted him up without any problem, though he only weights 150 lbs, but it was a piece of cake. I think I can keep thing simple and forego the 2:1 block, and just use the winch. I went ahead and bought a spare winch handle, just in case I loose one in the water. Would be quite a predicament not being able to winch the board up.
DLT,
The hardware issue was the biggest area of concern that my dealer brought up. Having stood on the steel plate with my 200 lbs and bouncing up and down on it with my full weight, I didnt seem to budge it. Also, with the test mentioned above, the hardware and cheek block showed no sign of trouble. I will start testing it in light winds, hopefully and watch the hardware carefully. If it shows that it may be starting to fail, I will beef up the plate & roller and the cheek block. For now, Ill keep my fingers crossed.
I talked with Joel on Friday, and he said the board is still 2 weeks from shipping. Kind of a bummer, since he also has my stock board and the weather is finally getting nice here. Sucks to be grounded. Im anxiously waiting to get the new board and go sailing. Ill be sure to take photos and post my results.
PS. Does anyone understand Roger's math regarding the draft of the
? Either his math is off or I'm not seeing something here. The DB trunk is 73". The board is 70". You are supposed to lower the board exactly 57" below the level of the deck. That means that you have lowered it 3" just to be flush with the trunk opening at the bottom of the hull. That leaves 54" in the water. The draft of the boat, board up is 12". Based on the numbers above, the drat should be 5'6" The Mac web site has the draft at 12" board up and 5'9" board down. Anyone with an explanation 
Cheers.
Unfortunately, I didnt take any photos of the broken board. I gave it to the dealer to take to the Mac factory to see if they would replace it. They didnt, saying it was my fault. I never saw the broken board again. From what I recall, there is a thick cross section of fiberglass running through the center of the board, sort of like a T. This leaves four cylindrical chambers which are hollow. That should accommodated the pipe idea you are planning on. I would be careful with mods to the existing board, however. I remember the exterior glass being quite thin. It appears that it wouldnt be very strong to hold up the added weight. Also, everyone I talked with, including two boat shops and my dealer cautioned that adding lead to this hollow, thin board would likely result in the board breaking under load. This is why I decided to have a custom one made. If you do proceed with your mod, you will likely find the empty portions in about 1 or more from the corners of the board. Just avoid the center bulk section which is where the solid glass T section is.
Frank,
The M hardware for the DB consists of a steel plate on hinges, flopping over and resting on the deck right over the DB trunk opening. This plate has a built-in roller, going one way to starboard which runs the uphaul line from the Db to the cheek block at starboard and aft. The hole is for the stop line. I went ahead and installed a rope clutch on the starboard side, just forward of the winch. Running it to port didnt seem practical. I did some tests with the dealer, running it to port and the additional block just added more friction and the reverse of the lines rubbed against each other as well. Since there are only 3 in the trunk (73 trunk and 70 board, there wouldnt be much room for a block. Also, there would need to be an additional attachment point, probably a second hole in the plate, which I am reluctant to do, since it may weaken it somewhat. With the tests I did with the dealer, winching 200 lbs was not a problem for me at all. This was done with me standing on a wooden block, placed on top of a stock DB and Jeff winching the board up with me on top, lifting me up. I then lifted him up without any problem, though he only weights 150 lbs, but it was a piece of cake. I think I can keep thing simple and forego the 2:1 block, and just use the winch. I went ahead and bought a spare winch handle, just in case I loose one in the water. Would be quite a predicament not being able to winch the board up.
DLT,
The hardware issue was the biggest area of concern that my dealer brought up. Having stood on the steel plate with my 200 lbs and bouncing up and down on it with my full weight, I didnt seem to budge it. Also, with the test mentioned above, the hardware and cheek block showed no sign of trouble. I will start testing it in light winds, hopefully and watch the hardware carefully. If it shows that it may be starting to fail, I will beef up the plate & roller and the cheek block. For now, Ill keep my fingers crossed.
I talked with Joel on Friday, and he said the board is still 2 weeks from shipping. Kind of a bummer, since he also has my stock board and the weather is finally getting nice here. Sucks to be grounded. Im anxiously waiting to get the new board and go sailing. Ill be sure to take photos and post my results.
PS. Does anyone understand Roger's math regarding the draft of the
? Either his math is off or I'm not seeing something here. The DB trunk is 73". The board is 70". You are supposed to lower the board exactly 57" below the level of the deck. That means that you have lowered it 3" just to be flush with the trunk opening at the bottom of the hull. That leaves 54" in the water. The draft of the boat, board up is 12". Based on the numbers above, the drat should be 5'6" The Mac web site has the draft at 12" board up and 5'9" board down. Anyone with an explanation Cheers.
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baldbaby2000
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