What made Pilot Cutter so fast? Just rumors?

[Bowdrie]

Originally Posted by MicHughV

Before the arrival of the WEST system epoxy or other epoxies, this was also a material that tended to be oversized.

Ok, my memory might be out on a limb with this as far as some details, but I do remember seeing ads for "Epoxy Resin" in the early '60s from some company that I've long since forgotten about, (and it was a room temp cure).
It was produced by Shell Oil Co. and was called "Epon", (whatever that meant).
This was a couple of decades before "WEST" was on the scene.
My understanding was that the Gougeon brothers got started, (apart from personally using epoxy to build iceboats,) was that they "read-the-tea-leaves", and saw a business opportunity, and they started buying the Shell product and packaging/marketing it in smaller quantities that the average person could/would buy.
In the '70s, I remember seeing ads in the boating magazines for boats made by Tillitson-Pearson, that offered as an option, a hull laid-up with epoxy resin, (at, in those dollars what was a premium price).

[TrentePieds]

Since you are in the PNW, you may recall a product called "Cold-Cure". It was put out in the early '70s by Jim Peters in Coquitlam (Vancouver, B.C.). The stuff would cure under water - yes, really!

Jim started a firm called "industrial Formulators", and he was the "go-to" man for all sorts of epoxy formulations back then. He was not a sailor, but he was enormously helpful to me when I replaced the foredeck on a Flying Dutchman dinghy and put a "cuddy" on a Soling to make 'er a "Cruising Soling". Beat the bejapers out of the Cal20s that abounded in English Bay then :-)!

Haven't seen Jim for years and he may be no longer with us, but Industrial Formulators has gone from strength to strength. 'Sfar as I know Jim was not a university-trained chemist but did what he did on the strength of a mere BSc in Chemistry.

TP

[MicHughV]

I was watching the replay of the 1983 America's Cup....when the "winged keel" first arrived on the scene.
Fast forward to today. Today's AC boats are massive foiling boats capable of stupendous speed.

Let's turn to the sails. AC boat have square topped adjustable double skin mainsails that replicate a true airfoil as near as damnit.

Crew talk to each other via helmeted microphones...

In yonder years, sails were cotton. Today sails are formed from exotic materials formed on moulding beds to control the exact shape desired once hauled up.

Modern electronics can dictate every move you or your competitor are likely to take.

And the list goes on.....one can but only ponder the future

[Lee Jerry]

Originally Posted by NewAlexandria

I'm leaving for 5 days into mountains to climb and ski. You guys have tons of time to recalculate this and prove me wrong. I'll be back.

Two weeks later...


Maybe our intrepid troll has finally figured it out.

[NewAlexandria]

Below are 3 images. Figure 4 shows what happens to 3 imaginary cubes in water. First cube is built out of aluminum, second cube is built out of water, third cube is built out of wood. You can see their apparent weights and water lines. The volume for each of those is 1 cubic foot.

Fig 4:



Figure 2 and Figure 3 show the correct apparent weights for my aluminum 3 by 4 by 3 boat and the aluminum cube if I melted my boat into a cube. Both starting weights on land are the same.

Fig 2. This is my boat melted into aluminum.


Fig 3. This is my boat from aluminum.



This is pure Archimedes Principle. If you don't understand something just ask. This will be important to understand before I move into stability.

[Lee Jerry]

Originally Posted by NewAlexandria

Below are 3 images. Figure 4 shows what happens to 3 imaginary cubes in water. First cube is built out of aluminum, second cube is built out of water, third cube is built out of wood. You can see their apparent weights and water lines. The volume for each of those is 1 cubic foot.

Fig 4:



Figure 2 and Figure 3 show the correct apparent weights for my aluminum 3 by 4 by 3 boat and the aluminum cube if I melted my boat into a cube. Both starting weights on land are the same.

Fig 2. This is my boat melted into aluminum.


Fig 3. This is my boat from aluminum.



This is pure Archimedes Principle. If you don't understand something just ask. This will be important to understand before I move into stability.

Wow! Still at it. And once again, so so much wrong. A few of the highlights...

In Fig 4, at the bottom right, you say of the wood that the "WL = 72%." 72% of what? That's a meaningless statement. (And the wrong number.)

How does the weight change from over land to the water? Weight equals the mass of the object times the acceleration due to gravity, or W = mg. Is it the mass or gravity that changes when you go from land to water?

The related question is: how does the center of gravity change?

Do you understand the concept of 'equilibrium?' Do you understand the concept of 'balance of forces?'




And a couple from before:

Originally Posted by NewAlexandria

If I'm wrong how come the boat that weights 464 on land all the sudden has a weight of 2,248 on the bottom of the ocean?

*obviously she would have to be sealed and weight added in somehow magically.

To answer your question, more information is needed. To use your word, the 'boat' doesn't magically appear at the bottom of the ocean, so how/why is it there? And is she in equilibrium?

Four possible options are:
1. Weight was added (in sufficient quantity) to exceed the maximum buoyancy available *, and she sank.
2. A hole (or holes) was put in the 'boat' so that water enters the hull, buoyancy is lost, and she sank.
3. An external force is acting of the 'boat' that exceeds the maximum buoyancy available, similar to #1.
4. A temporary external force or other factor is/was acting on the 'boat' (such as the hand of G-d pushing down, or maybe it was dropped from a height and momentum took her to the bottom) and when it is removed, the 'boat' will rapidly rise to the surface.


* The density of ocean water is generally considered to be 64 lb/cu ft, and therefore the buoyancy at the bottom of the ocean (if intact) would be 2304 lb.

Originally Posted by NewAlexandria

You all view things as if they were on land all the time, because on land apparent weight is equal to it's true weight. There is only gravity acting on all objects. No other force.

Originally Posted by NewAlexandria

My weight on land happens to be as my mass due to gravity only. No other force.

No, when you are standing on land the weight force is pulling you down and there is a normal force of equal value (provided by the ground) pushing you up. That's why your feet start to hurt after a while. You can measure these forces quite easily by standing on a bathroom scale.

Originally Posted by NewAlexandria

Once in water, [snip] my force is different and my mass is the same.

When moving from land to water, the normal force provided by the land is replaced by the buoyancy force provided by the water (of whatever value is appropriate). This is easy to measure with a load cell from above while lowering the object into the water - the force starts out equal to the weight and decreases as the buoyancy force increases as the submergence increases (until the buoyancy equals the weight, the object starts floating and load cell force goes to zero).

Originally Posted by NewAlexandria

Go read college simple publications and they will explain you when boats sink:
Here is one: https://scienceclass.dreamhosters.co...20Buoyancy.pdf

Did you read it? It supports everything I've been saying, and nothing you've said.

Originally Posted by NewAlexandria

Boats float because their apparent weight forces are negative. BUOYANT force is more than WEIGHT force. So therefore boat can't be 464 lbs in water. According to you BUOYANT force is equal boat's weight. Meaning, no BUOYANCY.

To me (and I would posit most everyone else) "buoyant force" and "buoyancy" mean the same thing. They are synonyms. Therefore, if there is a buoyant force, then there is buoyancy. If you think they are something different, you will need to explain.

Originally Posted by NewAlexandria

Fb = w - the w in here does not stand for weight of the boat. It stands for the weight of the water it displaces. My 7.44 cubic feet displace 464 lbs of water. If I push her down using 1782 more pounds she will displace exactly 2246 lbs. Her full weight force.

The 'w' does indeed stand for the weight of the boat.
The 'Fb' stands for the weight of water it displaces. This is indicated by the 'F' which is for force and the 'b' which is for buoyancy. Combined you get the 'force of buoyancy' or the 'buoyant force' or more simply just 'buoyancy.'
The '=' means that they have the same value (when floating statically).

[Bowdrie]

Originally Posted by Lee Jerry

When moving from land to water, the normal force provided by the land is replaced by the buoyancy force provided by the water (of whatever value is appropriate). This is easy to measure with a load cell from above while lowering the object into the water - the force starts out equal to the weight and decreases as the buoyancy force increases as the submergence increases (until the buoyancy equals the weight, the object starts floating and load cell force goes to zero).

A very good explanation that even a high school student should understand.
There is no hope of meaningful conversation with someone until they grasp that "truth".

[Bowdrie]

Alex, take a boat, and we'll presume it has the capability to float.
You could lower that boat into a pool of gasoline or a pool of mercury, and while the position of the waterline would change the "truth" does not.
Whatever the density of the fluid, the WEIGHT of the volume of the fluid that the boat displaces will still be equal to the weight of the boat as if it were weighed on a scale on land.
Fourteen pages ago you asked what made a pilot cutter so fast, within a few pages you tell us that every naval architect since Noah was all wrong and that you could design the perfect boat.
You've been trying to climb up one line of an endless loop that's suspended from a pulley, it ain't working out so well.

[NewAlexandria]

Skiing almost over. Be back soon. One more trip to Snowmass for hiking and skiing.

[NewAlexandria]

...and we'll continue.

[Don C L]

...nah, let's all just go sailing...