Lost power in heavy seas - which hull shape?

[kach22i]

My experience in the open sea is ZERO, so I've learned a lot in this thread.

Days of my youth spent on the Rouge River and Detroit River, plus a little Great Lakes action and inland lake experience fishing has been enough to get me to thinking that there is much to learn, and much to respect when around water.

As some of you may know my thing is "hovercraft". Few watercraft are as flat bottomed as hovercraft, so you might see where I'm viewing this topic from. A hovercraft with retractable daggers and retractable keel, one day I'd like to build one.

As an FYI below are two hovercraft at sea stories. What you walk away with is that "off-power" and in rough seas, a hovercraft would not be the first choice in "hull shapes".

Story-1
The World's first rescue by Lifeboat of a hovercraft
http://www.rhyl.lifeboat.btinternet....hovercraft.htm
(click link above for story and pictures)
...........................................................................

Story-2
Loss of 5 lives by rescue attempt
http://homepage.ntlworld.com/graham.alland/mypage2.htm

On the 4th March 1972 Hovertravels SR-N6 012 overturned off Southsea with a loss of 5 lives. The craft that runs between Southsea and the Isle of Wight was hit by a very large freak wave that turned it completely over about a mile offshore I was once again on "blood"...................

The Hovercraft in happier times

[TeddyDiver]

Originally Posted by kach22i

My experience in the open sea is ZERO, so I've learned a lot in this thread

You ask about hull shapes and we talk about buckets

[charmc]

Originally Posted by kach22i

What you walk away with is that "off-power" and in rough seas, a hovercraft would not be the first choice in "hull shapes".

"Finding that there was nothing on the hovercraft to which he could make a line fast ..."

More than just hull shape, there seems to have been some basic marine issues neglected in early hovercraft designs. Designers thinking "aircraft" and neglecting "boat" aspects.

[kach22i]

Originally Posted by charmc

"Finding that there was nothing on the hovercraft to which he could make a line fast ..."

More than just hull shape, there seems to have been some basic marine issues neglected in early hovercraft designs. Designers thinking "aircraft" and neglecting "boat" aspects.

I have tow connections on my small hovercraft (1989) and have used them three times on water (towed twice, once towed someone else) and they quite handy on land to grab on to.

[charmc]

Yup, you get it, George! Gotta have that boat stuff in the design if you're going to travel on water!

[kach22i]

UPDATE: 02/28/2008

Daggers and Keels.....retractable.....I had a vision of what that might look like, thinking of setting them at 45 degrees and doing both tasks at the same time.

Did I say that before?

Then I found this post by forum user Docker:
Mini Tug

Image alone:
http://boatdesign.net/forums/attachm...3&d=1172929062

Related images and text here:
http://www.rugludallur.com/index.php?id=28


Good article and pictures:
http://www.aeroyacht.com/NEWS/Articles/daggerboards.htm


Around The World Of Sailing
http://www.torresen.com/sailing/cont...es/2004_11.php

Canting keels which swing to windward to provide righting moment are superior to water ballast due to weight. When a boat ballasts itself with water it gains weight, getting more stable yet heavier.

I'm not really sure what this is:
http://www.projectsomewhere.com/2007...-a-bendy-keel/


Lifting Keel thread:
http://www.heymanyachtdesign.com/in3a.html

Article posted by Yipster:
ajustable lift keel