[Rhodes22-list] The Cat

[David Bradley]

Robert, that was what I was thinking about the ferries in Puget Sound.
 I bought a radar reflector and plan to hang it from the spreader,
using a 1/4" line and two rail-mount blocks that will fit the
spreader.  I have been haven't put the pieces together yet, but I have
them in the trunk of my car, aging a bit.  Tell me if you come up with
a better solution.

Dave


On 9/18/07, Robert Skinner <robert at squirrelhaven.com> wrote:
> I'm thinking that a major radar reflector AND plotting
> radar ping detector might be a damn good idea.  We Maine
> cruisers now have to deal with a 55 MPH catamaran ferry:
>
> See http://www.catferry.com/the-ship/general-paticulars.php
>
> >From http://www.catferry.com/press-room/press_2006_05_01.php :
>
> "The CAT is a wave-piercing catamaran car and passenger ferry,
> manufactured by INCAT of Australia. The vessel is 320 feet
> long, and is powered by four 9,500 horsepower marine diesel
> engines that drive a water jet propulsion system that could
> fill an Olympic sized swimming pool in 33 seconds.  The CAT
> can travel at speeds up to 55 mph, while its trim tab and
> T-Foil ride control system ensures a comfortable ride for
> passengers. Constructed of enough high-strength aluminum to
> produce 32 million beverage cans, The CAT is a technological
> marvel."
>
> Or from a coastal cruiser's point of view, a HOLY TERROR!
>
> I am considering having a ping detector hooked up with an
> alarm to wake me if I'm snoozing.  At 55 mph, it is
> traveling just a bit less than a mile a minute, or 88.5
> KPH.  So what's the problem?
>
> The straight line of sight distance d in kilometers to the
> true horizon on earth is approximately
>
>         d = (13 x h) * 0.5
>
> where h is the height in meters of the observer.
>
> Given a radar unit on the Cat 20 meters above waterline, a
> reflector and/or detector on the top of my sailboat mast 6
> meters above waterline, and the curvature of the sea
> surface, I would be visible from a distance of about 25 Km.
> At 88 KPH, that would allow 17 minutes to see my tiny blip
> and avoid my being sliced in half then ground into lobster
> bait.
>
> I question the wisdom of expecting a coffee-swilling deck
> hand on night watch to spot my little blip, get permission
> to take evasive action, and do it in time to save my butt.
>
> So Edith P. better be able to detect the ping, sound an
> alarm, and plot a constant bearing closing.  Especially if
> I am (was) hove to for a nap.
>
> Puts me in mind of "Bert & I"'s Bangor Packet story.*
>
> /Robert "What Cat?" Skinner
>
> * http://www.bertandi.net/
>  http://www.bluewaterweb.com/BosunsLocker/Locker.asp?SKU=001015&TopicID=168
> __________________________________________________
> Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
>


-- 
David Bradley
+1.206.225.7793
dwbrad at gmail.com