It should not surprise any of you that have been around for a while that I
would have a rather "non-standard" opinion on the whole matter of boats
getting thrown up on the beach by a storm, and then being dragged back into
the water by tow boats. One of my objectives in my decision analysis when
I select what sort of boat to build is that it must be able to survive this
sort of treatment with no more than cosmetic damage. The bottom must be
able to take it, the boat's structure must be able to stand the tow line
loads, and the boat must have a substantial means of transmitting those
loads into the boat without tearing stuff up. As it turns out, this
catamaran design was not terribly difficult to adapt to meet these
objectives. (A monohull is not so easy to adapt to these objectives,
unless it is a steel or aluminum boat.) I will even be able to drag Doulos
up onto the beach using her own winches, and then drag her back out again.
The keels are very long, but very shallow and wide. That puts a lot of
surface area on the ground. Then the bottom surface of the keels will be
clad with an airboat polymer, the same stuff that enables airboats to do 40
mph or more down a paved road with no damage.
If I had a typical fiberglass recreational trawler, and if it had to be
returned to the water after a storm like this, then I would much prefer to
lift it with a mobile crane. None-the-less, it is very likely that I would
drag it anyway after I got the estimate on the crane. In many cases, it
would be cheaper to repair the abrasion damage to the hull than to pay for
the crane. A crane large enough to lift Doulos out of a spot like this
would cost at least 15K, and could easily be ten times that depending upon
the circumstances. Transportation to and from the site could exceed the
rental costs. Don't be too hard on the folks who made the decision to drag
the boats.
My bosses recently asked us to prepare to rent a crane to replace one of
ours that was going to be down for service. This was about the same size
of crane that you would want to lift a 49 Krogen out of a tight spot. I
could either rent a hydraulic crane, which is cheap to transport and set
up; or I could rent a conventional lattice boom friction crane that was
very expensive to transport and to set up. The daily rate for the
hydraulic crane is much higher than for the friction crane. The break even
point considering all costs was about three weeks of rental, so you would
clearly want to rent the hydraulic crane for this task. That worked out to
30,000 dollars per day. Needless to say, the bosses decided that they
would rather reschedule the work, so that they did not need a crane while
ours was down for repairs. If the boat gets to be just a little larger
than that, and if the crane cannot get right up next to it to perform the
lift, then the cost of the lift could approach a million dollars. Disney
paid a million dollars for a single lift a few years ago, to put that huge
concrete swan up on top of that hotel. It also weighed about the same as
some of your trawlers. The Space Shuttle only weighs slightly more than
that Krogen. They are essentially the same weight, if the payload and the
engines are removed. Crane rental to lift that thing will run many
millions of dollars, due to the fact that the cranes simply cannot get
close to it. That means that you need much larger cranes to lift it. A
250-ton crane gets the light end, while a 900-ton crane gets the heavy end.
Both cranes are loaded to about 70 percent of capacity in this
configuration, due to the long reach. You could easily run into the same
problem when trying to reach and lift a storm-stranded trawler back into
the water.
The cleats pulling out concern me. Every boat needs to have some very
strong mooring attachment points, which should not pull out by dragging the
boat. I understand that many boats are not built that way, but they should
be.