Conference unifix::sailing

    RICK,
    My impression is that the ends and the 12"interval holes will have
    the track thru-bolted from the track, through the teak and the deck.
    Your diagram shows these as only through the teak and deck. Is the
    diagram wrong?
    
    My understanding is that the close thru-bolting is to eliminate or
    reduce changes in the track's shape. If you completely thru-bolt the
    track to the deck as you plan I would think your plan would be
    adequate. If the diagram is correct then I think you're putting
    all the strain on the teak which I don't think is a good idea.
    Remember, this is a Geography/Urban Studies major talking, not a
    mechanical engineer.
    
    The ideal solution would be to thru-bolt at all of the new locations.
    What are your reservations about doing that?
    
    Ed

    Rick,
    
    I would recommend you thrubolt at each 4" harken hole and plug the
    misaligned 3" holes.  
    
    Incidentally, the traveller track on my boat is bolted only with
    the outermost 3 holes (with steel backing plates) the rest of the
    traveller (about 2" or so in the center) is unsupported.  I have
    a 300 sq.ft. main and have never noticed any binding, or flexing
    of the track in the unsupported area, so maybe it isnt necessary
    to secure the track if its rigid enough.  Its also a Harken traveller,
    the crosssection looks something like this.
    
              __        __
              \ -------- /
               \  ____  /
               / /    \ \
              / /      \ \
             / /________\ \
             |____________|

    Good luck,
    Walt

    Re:.2
         I wrote 2" as the unsupported area,  I meant 2' (feet).
    Walt

    I own a wavelength 24, that I replaced the traveler system on two
    years ago. The old system would bind up. I replaced the old system
    with a Harken Blue car on the "high" profile track(recommended for
    tracks that traverse open cockpits). I also installed bullet blocks
    on each side of the car and also on the deck of the boat, also on
    the deck I put an eyestrap. sounds a little complicated but in the
    end I have a 2-1 system, which my wife can handle. Incidently, i
    wrote harken and explained to them what i wanted to do, they inturn
    recommended which model number blocks to use for my boat. Is harken
    the right one to use?-harken is the "only" one to use!
    Don
    

  Re .1:  The diagram shows *only* the places where I cannot
          thru-bolt.  I intend to thrubolt whereever a hole lines
  	  up.  Remembering my 3rd grade math and least common
  	  crud, this seems to be 12 for 3 and 4" holes.
  	  The idea is that 5 bolts would go from track all the
  	  thru the teak and deck and be secured to a baseplate
	  below.  The holes which did not line up (4 "" from  track)
  	  would  be brough down into the teak only (not further) by
  	  countersinking the teak to accomodate a large washer and
  	  bolt head while still keeping the teak block flush.  
  	  The 3" holes from the deck going up (left over from the
	  old system) would be used to secure the teak block in
  	  the same manner.   The teak holds the track at 4" intervals
  	  and the deck holds the teak at 3" intervals.   And *only*
  	  for those locations that don't line up.
  
  re Walt: I wouldn't mind redrilling new holes, but I hate to
  	   make that section weaker by doing so.  I'd also like
      	   to put the old traveller back when I sell the boat.
  	   I'd have to drill out the plugs I put in later and plug
  	   the 4" holes I just made.
  
  Right now it seems as if redrilling the holes is the easiest
  alternative.  Does it affect the strength of the glass
  significantly?  I'd think not, with a good backplate being used.
  
  Rick                              
  
  * Whose Computer Science/Corporate Finance major didn't prepare
    me for this either.
  

    Rick, Is the mounting surface on the boat reinforced, like with
    plywood or balsa coring ?
    
    These cores will do a nice job of spreading the backing plate loads
    from the thru-bolt-every-12" bolts to a large area of deck.  If
    you have solid GRP here the load will be spread over the backing
    plate area and thats about it.     In the first case, using only
    the 12" spaced holes for bolting, with backing plates, should give
    you the strength you need (assuming you can get 4-5 bolts in and
    the track is a high profile type which can span 12" without support).
    Then you could just bed the teak and have it seal the unused holes
    in the deck.    If you have solid GRP though I recommend you thru
    bolt as often as possible to spread the load as much as possible
    (unless this area was specially reinforced with extra layers of
    glass).
    
    I tried to imagine how one would go about assembling the system
    you described in .0 and cannot see how you can get to both ends
    of each bolt with a wrench (except the ones every 12" that thrubolt).
    How do you plan to keep the bolts who's heads are buried between
    the traveller and teak from turning while they are tightened ?
    
    Walt
    

As a physicist by training (though no longer by profession), I would 
like to offer a contrary view to the last reply. 

If you have a balsa cored deck, you will crush the balsa when you
tighten the mounting bolts for a fitting that is through-bolted. Also,
heavily loading a through-bolted fitting will tend to crush the balsa.
Rather soon the mounting bolts will be loose. Every book and article I
have seen recommends cutting out the balsa and filling the hole with
either solid glass and resin (preferably) or with plywood (which is much 
more crush resistant than balsa). In either case you need a backing plate 
to spread the bolt loads over as large an area as possible. 

I would recommend through bolting the traveler every 4" just as Harken 
intends. They put the hole centers on 4" centers because they don't want 
a failure. Neither do you. Mainsail sheet loads can be quite high. 
Imagine the traveler car sitting over a mounting bolt. Neglecting the 
strength of the track, that bolt is carrying the entire mainsheet load. 
I don't know how big the mounting bolts are, but (give or take a bit) 
the mainsheet load can exceed the safe working strength of a 1/4" bolt 
(800 pounds is my estimate). By the way, you don't have to break 
anything to have a failure. Your current traveler car binding is a 
failure (it has deformed enough not to move). Cyclical heavy loads will 
cause stress fatigue and eventual failure. They will also tend to break 
the joint between the bolt and the bedding compound.

I would through bolt the traveler and sell it with the boat. The effort 
of removing an N year old fitting to save a few dollars wouldn't be 
worth it to me. 
    
As an aside, the articles I have read lately (the one in TIME being the 
most recent) about lawsuits for negligence have concerned us enough to 
seriously consider no longer chartering our boat. There are simply too 
many ways to hurt yourself on a boat, and it is hard to imagine that a 
victim couldn't find a way to blame the negligent owner.

Alan

    Looks like the recommendation that is the first one out of each
    reply is thru bolt it every 4" with a backing plate.  You cannot
    go wrong.
    
    I think many of the other solutions can also work in some cases,
    depending upon deck construction, traveller track design and the
    piece of teak in between, but each is less trustworthy than the
    consensus.    Alan is right about removing it when you sell -
    you shouldnt pick your next boat according to whether this track
    will fit or not, and odds are you either wont need a new one or this
    one wont fit anyway.
    
    
    An aside on Alans response to the balsa core thing.  He is correct
    in that a balsa core can be crushed by the compression of thru-bolting
    a fixture that carries heavy loads like a winch or traveller. In
    this case the best solution would be to remove a balsa donut around
    the hole and fill it with GRP.  This takes the compression from
    the bolt off the balsa.  A backing plate larger than the donut will
    then help distribute the sheet loads into the GRP/balsa sandwich
    deck and here the balsa will help spread the load out over a larger
    area than would be the case with solid GRP decking (again assuming
    the deck was not specifically reinforced in this area with additional
    roving or mat).
    
    Walt

    re. GRP donuts 
    
    (Walt, by any chance, would you be of English extraction?) 
    
    Would it be simpler to reinforce the deck (underside) by glassing in 2
    or 3 layers of tape or mat (which would be better?) that exceeded the
    teak block dimensions by 2-3"? The backing plates would sit on this
    deck reinforcement.
    
    Ed 

    ED, I think that added mat/tape/roving reinforcement would be a
    good idea under any conditions - except I hate trying to get the
    stuff to defy gravity untill it sets up.   The reinforcment donut
    doesnt exactly go on by itself but being limited in size (as well
    as easy to thicken with microballons) its a bit simpler to manage.
    Besides, there is still the problem of thru bolt compressing the
    balsa.
    
    I watched a fellow install a Pedistal/Wheel steerer last spring
    on a solid GRP cockpit sole.   He first installed the unit and
    the pedistal guard thru the sole to backing plates the size of the
    pedistal and guard.  We tugged at the top of the guard and watched
    the deck flex immediately adjacent to the pedistal.  He wasnt happy
    with this and glassed in a 1" piece of plywood under about half the
    cockpit sole.  I stayed away during this time (working on my boats
    bottom) but recall a lot of explitives while he was trying to get
    the saturated roving to stay up untill it cured. He even had to
    cut himself loose from the boat one day after some of his hair dried
    in a glop of resin on the hull, while he was pushing parts of the
    cloth back up.    Anyway, the result was impressive. The added GRP
    and plywood virtually eliminated any movement of the pedistal, and
    when pressed to move, the deck flexed over a wide area (the load
    was spread).
    
    (Do I write with an English accent ?  Actually I have Scottish
    ancestry)
    
    Walt  

Fiberglass (more correctly, GRP) is not all that stiff in panels. Three 
layers of 1.5 oz matt alternated with four layers of 7.5 oz cloth is only 
about 0.125 inch thick and is quite flexible. One way to make a donut 
compression pad is to drill a one inch diameter hole with a hole saw 
through the underside of the deck and the balsa (the top layer of 
fiberglass is usually a good bit thicker than the bottom layer). Slap a 
strip of duct tape over the hole (from below) and then fill the cavity 
from above (through the 1/4 inch pilot hole for the hole saw) with 
epoxy, thickened with microspheres or some such is you'd like. Presto, 
a glued in place donut.

Alan

    re. .10
    I've only seen "GRP" used by British writers so I was wondering
    if you were English. Actually, from my perspective, you speak with
    a distinct VT200 accent.
    
    I'll make sure I wear a hat when working the sticky stuff!!
    
    re .11
    I didn't realize the tape and mat would be that thin AND I was assuming
    they'd add considerable stiffness. Hopefully, my store of ignorance
    on working with GRP will be reduced by the end of May. My only
    experience is taping in some plywood shelves in the cavern 'neath
    the cockpit on the ol' Pearson 26. Pretty tame stuff  
    
    Gotta run...
    
    Ed

    Ed - instead of using tape (too thin and flexible) use roving (looks
    like
    straw matting, much thicker than tape). Also, thr trick in glassing
    overhead is too use as little resin as possible, which in turn means
    you need the proper rollers to saturate the mat-roving-mat-roving-mat
    layers. I have the rollers if you want to borrow them, I may have
    some roving kicking around...
    
    Henk (who build his own GRP 30 footer from scratch - never
    again...unless it's a 45 footer).
    

    Hmmm... the donut idea seems pretty smart.  Kind of like the old
    reinforcers on notebook paper.
    
    The consensus seems to be to thrubolt at 4" and worry
    about removal and replacement of the old system (if that happens)
    later.  Its probably easier in the long run.  I *might* be able
    to get by with every 12", but if drilling a few more holes will
    eliminate any risk Ill do it.  Ill bed the teak and plug the old
    holes.  
    
    Re .6:  I know what you mean.  It would probably have to be assembled
    such that the traveller goes to the teak, and then the combination
    to the deck.  Since I'm probably not going to do it, I won't spend
    to much time figuring that one out.  I hadn't given the process
    much thought.   
    
    Rick
    
    * Proof that any simple idea can be made complex if you try hard
      enough.
      

    I just read all the interesting info about 'glassing, and so. Very
    good info. After all is said and done, your Harken traveller system
    may still bind. Assure that when the boom is centered, the line
    drawn from the traveller car to the boom attachment angles at least
    slightly aft.
    
    The typical binding problem is when the sheet is tightened hard
    while upwind. When you go to spill some air by releasing the traveller
    a bit, you find you need to kick it, etc. The problem can be easily
    seen by drawing a crude "T" and follow a point in front of the
    traveller as is traverses, and then behind it. "Aha!" you say. "There
    is a cause of binding, but if the attachment is behind the traveller,
    it will bind bringing the traveller to weather from a reach (or
    a wind spill)!" Well...yes, but you usually don't have the main
    sheeted that hard on the reach, and so there is slack there, and
    on an ease, you don't adjust the sheet anyway.
    
    Now for all you who are about to yell and scream about how wonderful
    the Harken stuff is... you're right... I use it too, but just because
    gear is engineered to work well under severe stress is no reason
    to attempt to stress it any more than need be.

-------------------------------------
| boom                              | gooseneck
-------------------------------------
 block 1        block 2           block 3
   \ \           / /----------------|
    \ \         / /                 |
     \ \       / /                  |
      \ \     / /                   |
       traveller                    |
     fiddle block                   |
                                    | turning block
cockpit winch <----------------------

This mainsheet sheeting arrangement seems to avoid traveller binding
problems on all points of sail, at least on our 32' boat with a six year
old OEM_not_latest_and_greatest traveller. The sheet begins at the
becket on block 2, down to the upper sheave on the traveler fiddle
block, up to block 1, back to the lower sheaves on the fiddle block, up
to block 2, on to block 3 at the boom gooseneck, down to the deck
turning block, and back to the cockpit winch. As long as the blocks and
traveller bearings are kept nicely lubricated, the traveller car can be
moved fairly easily, even close hauled with the lee rail down. The boat 
arrived from the builder with this system, and since it works, we 
haven't changed it. Of course, going from a broad reach to close hauled, 
you get to marvel at the niceness of a self-tailing mainsheet winch for 
a long, long time as you crank and crank and crank. Since the boom 
blocks are actually at midboom, the 4:1 purchase is not too little close 
hauled in a breeze.

    A good boom vang installation will do a lot to unload the mainsheet
    upwind.  I found that the traveller only became difficult on our
    boat when I was trying to use the mainsheet to control sail shape
    instead of using it to set angle of attack to the wind and using
    the vang and backstay to set the shape.
    
    When we got our boat it had no vang and a 5:1 mainsheet 3:1 traveller.
    I was tempted to go to a 7:1 sheet because of the work I had to
    put in to the sheet to control the sail up wind in a breeze. Once
    shaped you could forget pulling the traveller to windward.  A friend
    who raced Tartan 10s suggested the vang instead of a new sheet system.
    He felt it would ease the strain when close hauled and certainly
    give me better control reaching and running. He was absolutely correct.
    Aside from the speed increases off the wind, my wife (half my size)
    can sheet the main single handed in the same conditions that I used
    to use both hands and a braced foot.
    
    Walt