Catamaran Evolution

J, with the weight and fast hulls I think your boat will want to slide down a big wave and dig deep at the bottom. I think anything that will help to slow it down and keep the boat level would be good....in huge waves. I guess its only the huge waves that'll fill your transom. Huge ships are often designed to dig their stern into a following sea.....stops them from broaching.
My boat is light so that's an advantage but I expect I'll be using 'human' ballast instead.

 

Hello Richard,

Nothing is going to blow a hole out of anything. Lightning rod at the masthead connected to a 4 gage cable running down its length through the bottom of the mast with enough cable to deploy a couple of feet into the water directly below will be the most direct and least resisted path to ground.

Static charge is caused from an imbalance in positive and negative atoms and will discharge when grounded while it seeks equilibrium or neutral. Electricity is a funny thing and it appears that it may cheat, but, the law of physics, as the law of least resistance, must be obeyed because it is the law.

Everything grounded properly with back-up protection will in all eventuality save a life and route a strike to ground without any significant danger. Blowouts occur when a strike reaches a dead end and there is water in some form which would superheat, expand 1600 times and something has to give.

J

 

Hello...

I refuse to let the Green Lantern do that.

I will deploy a drougue, I will drag sheets, I will reduce canvas, I will quarter waves, I will deploy a chute and turn bows to sea, I will go to motors and head her up, I will heave to or go to bare poles and run...but I will not let her do that. In those conditions, all plans become secondary and only the safety of crew and vessel is important.

The Green Lantern will not be allowed to do anything that I don't decide should be done, when and how I decide it is to be done. A machine is only as good as her operator even if her design is such that she can inherently take care of herself.

Mother nature, Father time and the Green lantern better get used to the fact that I am in charge and doing with me as they please is a possibility but, they will be hard pressed because it will not be as easy as they anticipate if there is anything I can do to spoil their futile but well laid plans.

J

 

Well said

 

Hawdy all...

Okay. I have scaled the model to 1:12 and will begin construction on her soon. I will place the specifics in here next time. Stand by as I begin to learn the digital camera thingie so the project can be followed along. I'm still trying to work out some export/import issues with CAD, so those lines will have to wait.

The construction manual will be authored as the scaled project progresses.

Thanks
J

 

I will find it very entertaining, J. I am very much looking forward to seeing this.

- Richard

 

Hawdy all...

Okay. I had the stations and profile printed up today. I will now begin to get the materials for the model mold. I am attaching the scaled model specifics.
It looks like the hull all up will weigh in at 49.28 pounds and total sail area is almost 4sq'.

I have the digital camera thingie down, so pictures will be forthcoming.

Thanks
J

 

Just to prove some of us are awake!

At 12:1 scale it will sink.

Rick W.

 

Hello Rick,

I guess that's the wrench? Care to share your reasoning?

Now you have me thinking and worried. Maybe something didn't scale correctly? Maybe I calculated incorrectly? I'll look it over again. I guess this will be my first deployment of the drougue for braking effect.

J

 

My 24 ft boat weighs less than 49lb. My target is to get my HPBs under 40lb including the drive system. So I have no doubt your are out by a big factor like a decimal point in the wrong place.

Rick W.

 

Hello Rick,

You are definitely awake. Catastrophe avoided. Thanks.

I went back and checked everything. The areas scaled correctly as did the draft. However, the thickness and weights did not scale in the layers so I used the wrong figure for the calculation. I stand corrected.

The displacement scaled to .002 tons at the designed scaled draft, but I thought there may be some rounding off there so I calculated by hand. Here it is.

3.201tons x 2240 = 7170.24# = Non scaled displacement for draft.
7170.24# / 12^3 = 4.149# = Scaled displacement for draft.
It now appears that the all up scaled weight will be 4.15#. Huge difference.

Lessons learned.
1. Common sense is our friend and should be practiced.
2. Listen to Rick whether he speaks in his sleep or awake.

To put things in perspective and as a measure of my...ahem, well, my error, 49.28# x 12^3 = 85,155.84#, sooooo, yes, she would have sank at 12:1.

J

 

I never said anything inappropriate

 

Richard,

I have edited because it may be viewed as inappropriate to those younger than I and, don't want the wife breaking down my door.

J

 

I have edited mine too.... to destroy any evidence that this conversation ever took place.

 

catamaran?

hai all,.....

I want to ask something about catamaran?

I have plan to builld catamaran with spec:

LOA : 10m
LBP : 9m
B : 5m
H : 1m
Drft : 0,5m
material : Fiberglass

unfortunetlly, I confusing about the constuction of the ship....

can u help me to give information how to build this ship....
thanks