On Sat, Aug 28, 2010 at 04:22:21PM -0400, Ed Kelly wrote:
> Thanks for the gift of your thoughts and experiences Ben.
> I respect them.
Thank you, Ed; it's always a pleasure to see the things that you have to
say as well, especially when couched in such pleasant terms. I suspect
you're very popular with cats. :)
> The unit I got does not have any "TUBES".
> Mine has heavy SQUARE STAINLESS STOCK for Arms with an
> outside dimension of an inch or inch and an eighth.
Pardon my mischaracterization, then. The choice is bit surprising, since
a square cross-section is much more vulnerable to torsion than a round
one.
Even with the above correction, though, a 1"-or-so square rod still fits
into my definition of "inadequate" when it comes to supporting a dinghy
in heavy weather - at least in the configuration in which the DT uses
it. It's certainly possible to design a bullet-proof system based around
that structural shape, but that's not what the DT is, or does.
> These arms
> only about 42 inches long and anchor to the stern, by stainless,
> & are used at an angle when hauling the dinghy.
As I recall, the site has a good demo of how the system works - and
demonstrates that process quite well.
> YMMV but I would prefer the DT over the Davits as a boarding
> wave can wash off out of a dinghy on the dinghy tow. Similar
> to the connections on some swim platforms of power boats
> where he dinghy is carried on its side.
I always find it amusing to see dinghies in davits being held upright
rather than angled or, as I'd prefer to have it, griped in against the
stern: that tells me that the person isn't thinking about what can
happen at sea. Years ago, I met a cruiser in Bermuda who had quite a
respectable set of davits on his 50-footer, and he told me about a
passage in which his dinghy got swamped - a choice bit of weather,
considering that his dinghy was at least 7' off the water when lifted.
The davits held all through the rest of the storm, but the next time he
went off-shore, he stuffed the dinghy with fenders and lashed them in
place (seems he had enough of them to essentially fill it.) After a
couple of years of that, he changed tactics and rigged it to be stowed
upside down, and was very satisfied with that (not my personal
preference, but it would work.)
Perhaps those traditional methods hung around for hundreds of years for
a reason? :)
> I have talked to Davit Manufacturers at boat shows
> they have told me their share of horrors on boats that
> had dinghies flooded on in the Davits. No davit
> is made to hold a boarding wave and if one hits a boat
> in a dinghy in Davits, the force of the heavy weight and
> angle can break stuff too.
You might recall that I mentioned "disposable davits"; that's how I
refer to the typical "yachty" bolt-on system that's available at boat
shows. I would never claim that those are better designed than the
Dinghy-Tow... but I do admit that I mentally consign them both to the
same bin.
It's the classic problem: the market for top-grade sea-going boats and
boat fittings is very, very small. Since the manufacturers are in the
business of making money, they're trying to hit as much of the market as
possible. This means cutting down on reliability and functionality -
because those are invisible to non-professionals unless they're
*grossly* and conspicuously absent - so the price can be lowered to the
point where the average boat-owner is happy to spend the money.
I can't build a DT to my own specs. I *can* do so with a pair of davits,
relatively easily and at a cost that's much, much lower than either a
commercial set of disposables or a DT. In other words, unless the DT
people change their minds, there's never going to be one that's suitable
for my needs - but for davits, the correct design and materials are
already available, pretty much everywhere. In those terms, a DT can
never be suitable for my use - but for about $200 and 2-3 days of
fabrication and welding, I can have davits strong enough that my 13-ton
big boat can be picked up and suspended by them. That's no exaggeration,
just a simple fact.
> Thanks again for your thoughts.
And thank you very much for yours! Perhaps someone searching the
archives will find something of use in this discussion; you've certainly
given some good info on the DT that doesn't seem to be available
elsewhere.
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