Since the dinks been chewed up by the propshaft you might want to just leave it behind.... with your friend in it for engaging the props with you behind the keel.
Doing heavy lifts (not my line of expertise) the really hard part is at the surface. My old neighbour made the frame to lift King Henry VIII HMS Mary Rose from the 16th Centrary sitting in the sand off Southampton Uk. This guy spent hours and hours underwater studying how the ship had sat for hundreds of years. He made the frame and we all sat round the TV to watch the great lift. All was well until the main weight reached the surface, and CRACK, the frame broke. Saved but one or two squeaky moments on the leather sofa. When heavy lifts reach the top, a good lift platform is needed to control the change from water pressure to surface pressure. Fish
It depends on the bottom makeup. In clay/mud, the bottom suctions can be very strong, typical sand will have no "holding power".
MECHANISM OF BREAKOUT If an object is resting on the ocean floor without embedment and no adhesion develops between the object and the ocean sediment, then the force required to lift the object will be equal to its submerged weight. The value of the breakout force in this case, according to our definition, is zero. If the object is embedded and an attempt is made to lift it, skin friction or adhesion which develops around the sides of the object and adhesion along the base will resist the effort to lift it. The difference between the force now required to raise the object and the submerged weight is the breakout force. The contribution from skin friction and adhesion in many cases is only a small fraction of the total breakout force. Thus the mechanism for resisting breakout cannot, in most cases, be assumed to be due to skin friction and adhesion, and other mechanisms must be sought.
Anyone bored yet? This thread was set-up as a fun banter stream to give an outlet from all the BS of "The Other Thread". Have fun, we're all not perfect.
Boats suck! No, really. When a hull sits in an aluvial medium the surface tention adheres to the surface of the other property. Don't ask me the Laws, that was 25 or more years ago
Lifting of the wreck from its location at 50 feet below sea level began at 0700 local time and within two hours the first jagged edges of timber had broken the surface. Yet just before midday one of the pins holding the lifting frame sheared, a steel line snapped and part of the 80 tonne frame smashed down on the hull. Here is the article that bit came from. http://news.bbc.co.uk/onthisday/hi/dates/stories/october/11/newsid_2531000/2531561.stm
Thanks, but I was wondering how much time his neighbor spent on the project. It looks like he has a pretty good cradle built for the lift