"Bruce in Bangkok" wrote in message
...
On Sat, 29 Mar 2008 01:12:17 GMT, Jere Lull wrote:

On 2008-03-27 22:48:27 -0400, cavelamb himself
said:

Jere Lull wrote:


What you need is a casement for a tidal driven dry-dock. Float in, let
the tide go out and close the doors.

Something like that?


Why make it so complicated and expensive?

Just hoist the darned thing, fix the problem, then splash.

Sheesh! Sounds like a bunch of Mensans around here!



This IS a form of hauling - but could be a whole bunch cheaper and less
prone to hull damage.

Float in, settle into the slings as the water goes out. Then close the
doors for a dry place to work - until you are done.

Come to think of it, wasn't this technique used in the South Pacific
during WW-II?

We're talking CRUISING boats, in the current world, without the benefit
of a military budget. Large tidal differences exist, but are not the
norm in the real world of cruising.

Haul, fix, splash is the current state of the art for most cruising
boats. Technology has marched on in the past 50-60 years. Travel lifts
are now the norm.

(and we have a marine railway and other last-generation technologies
within our normal weekend range. We choose current technology.)


Over in the Philippines I saw a floating dry dock made of plywood. It
was essentially a barge with a cradle on it. They sank it in shallow
water, loaded the boat and blew the water out of the pontoons with a
compressor to refloat the thing. Home made rig, but worked.

The tide and sling rig isn't logical and I can't believe ever existed.
If you are working on the boat at low tide just prop it up on the
beach. Heck, they been painting lobster boats that way for a couple of
hundred years, or more. Probably been cleaning those oyster tongers
down your way using the same scheme.


Bruce-in-Bangkok
(correct email address for reply)

They are very popular here in Florida... trademark is Hydrohoist... they are
used to keep boats out of the sal****er. They are ugly but can be moved
and resold easier than a permanent lift.