I'm tying down a load (let's say a motorcycle) in the back of my pickup. I have metal ring tydowns on both the truck and the bike. I'm fairly sure I want to use two hitches for this. I'd like one of the hitches to be "tightenable" (maybe a driver's hitch?). The other one doesn't need this property.
Conceivably your initial anchoring knot could be a loopknot; were you to make it
with a large/long eye, up about 2/3 of the span to the motorcycle, then the other
side's structure could be a few half-hitch/turns, the last/uppermost of which would feed
the line across to grab the first side just below the knot, between the eye legs
(so to prevent this connection from slipping up higher). This connection would act
as a sort of "frapping turn", to pinch the anchoring legs into greater tension.
I'd like them both to be as strong as possible.
Not really: you shouldn't be close to finding out any difference between various ways of
tying the rope--that would show poor cordage selection (or some extraordinary
circumstance!). Given the suggested use & cordage, you've got nothing to worry about
for strength.
Second to that, it'd be nice if they were both reasonably easy to untie (although I'd cut the knots off the ends of the rope without too much remorse - is this sacriligeous?) I'll be using bullrope (http://www.knotandrope.com/bullrope.htm), mostly because it seems to be the stronger/est of the ropes I've looked at.
Yes, there'd be an audible gasp of horror (& also "Horreurs!" (?)) were this forum's members
to learn that you'd chopped that rope for this task. (then a lunge for the fiddly bits)
A point to much knotting is being able to untie it (though there is also a fair amount that
doesn't get untied), esp. in pricey bullrope.
Whatever are you REALLY tying down? --say an elephant? Those bull ropes are
way strong for any usual tie-down application. (I think that if you check with certain
webbing products suggested for a motorcycle, e.g., you'll find strengths around 3-6,000#?!
Common chain that might do such a job will be maybe 2-3,000#?
In getting such great strength, you're getting thickness & stiffness that might
frustrate tightening. (And what dia. are those rings you're tying to--likely about
1cm & maybe thinner--which isn't good for the thick rope.)
p.s. I'm hoping that there's at least some consensus on the two best knots for the job...
That's the wrong hope, really. There are many solutions to this problem; some might
turn on the question of how much rope you have--e.g., were you employing a long
bull rope normally used for lowering logs, and didn't care to cut it shorter, or if you are
buying the rope new per foot expressly for some job.
Indeed, I'd imagine that various folks here might each have different solutions
depending on their mood or maybe just what they'd NOT used the previous time!
But your sense of the solution is on target: one side more staticly anchored,
then the other used to adjust tension and finish. It COULD be the case that one
would want adjustability on both sides (for centering an object).
And some variation of the Trucker's Hitch could serve on each side, or just the one;
the other could have an Anchor/Fisherman's Bend (hitch), or a round turn (well,
given that thick rope, perhaps NOT!) & 2 Half-Hitches; or perhaps you'd not need
the MechAdvan. of the Trucker's H. and could tension manually well enough and tie
off with a turn/Half-hitch and backed up with a Rolling Hitch, putting an Overhand
stopper (or Slip-Knot) in the tail for security.
So far, all this discussion's been focused on the tie-down's legs; but what of the
exact nature of the thing tied down--tying to a bike's handlebars, or ... ?
That's another issue to address.
--dl*
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