[PUP] PPM, Round Tails, Big Rudders

[Patrick Gerety]

----- Original Message ----
From: Kevin Kearney
To: Passagemaking Under Power
List <passagemaking-under-power at lists.samurai.com>
Sent: Saturday, November
15, 2008 7:11:42 AM
Subject: [PUP] PPM, Round Tails, Big Rudders

>The design
question is--- is how well the boat surfs with a round tail, narrow tail or
squared tail?

I have a round stern trawler.  I have never been in perfect
storm conditions so I cannot comment about those conditions.  I have been in
conditions with seas approaching 20 feet.  I find in those conditions, I can
leave the boat on autopilot and experience yaw of about 3 degrees as the wave
train passes from astern.  The boat will surf to some extent but with no loss
of control or any tendency to bury the bow.  I have no idea how my boat would
behave in more severe conditions.

I do carry a large drogue off the stern for
lying ahull.  I would much rather expose my rounded stern to following seas
than my bow.  BUT, I have never had to do this, so I cannot comment
specifically how well this works.

>The relative merits of swim platforms in
following seas, the aft underwater profiles that make a boat semi-displacement
vs >displacement and the size of rudders.

I do not have a swim platform.  I
have not missed one.  I have boarding gates port and starboard for easy
boarding from either a dinghy or a dock.

My rudder is about 36" tall and 24"
wide.  It works fine.

>Methinks that flattened aft hull help put a boat up on
plane, that wide flat transomes help interior space but can lead to broaching,
and >that small rudders offer less control at slow speeds than larger rudders.
You are correct.  A round stern can lead to pinched interior spaces toward the
stern.

Patrick
Willard 40PH
ALOHA
La Paz, MX