Update : Does the exhaust manifold need to come off before changing spark plugs or is there a trick or special tool to use? Not enough room for regular socket and ratchet.

If the declaration of independence says "all men are created equal", then why the hell did slavery exist?

slavery means not all men are made equal but that some are superior to others by use of force or mental slavery(willie lynch letter). Also when I think of it...

Depends on what you are doing with the boat, of course.
- Short positioning trip - 2 people (skipper + crew)
- Large party for A-listers - 60 (caterers, wait staff, bar staff, entertainers, bouncers, band, safety crew).

The force of buoyancy is due to the fact that when you submerge a volume of mass into a fluid, you displace the fluid. Forcing it to ascend from where it was prior to the immersion.

And what goes up … wants to come down again.

There are two easy ways of lifting up two gallons of water:-

1/ Fill a bucket with water and lift it up.

2/ Push an object the size of a bucket of water into a swimming pool.

Both will take an equal amount of force. In (1) the force is upward (eg, supplied from your arm muscles in an upward direction) and in (2) the force is downward.

If in (2) the "object the size of a bucket of water" is full of water, (eg, a bucket of water!) then the downward force is supplied from the weight of water in the object, which will, in turn lift up an exactly equal volume of swimming pool water as you immerse it in the swimming pool.

If in (2) the "object the size of a bucket of water" is empty (eg, a vacuum, or air or other very light density material etc.,) an 'empty' bucket in other words … then the downward force is again from your arm muscles but in a downward direction. BUT you will still lift up an exactly equal volume of swimming pool water as you immerse it in the swimming pool. (Forcibly push it down into the pool).

So, if you like, there is a buoyant force because of the hydraulic effect that immersing something into a fluid (eg: water) has on the fluid: It lifts it up.

… And if you lift something up, it wants to come down again.

To focus on water - it is very heavy. A volume of water about equal to the size of your desk weighs one tonne. So if you want to make something the size of your desk sink beneath it, then you have got to supply a downward force of one tonne in order to move the one tonne of water there out of the way, in order to make way for your desk-sized object.

The force encountered in moving it out of the way is the upward force of buoyancy.

It is the equivalent weight (per-volume) of the volume of the desk-sized object - in fluid.
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Try it!

Try pushing an empty bucket into a pool. You'll find it takes as much force as lifting a full one. It's just that you will be pushing down as opposed to lifting up. But in BOTH cases you will be lifting up two gallons of water. One simply by lifting up; and the other by pushing down.

Against the force of buoyancy.