Mast Ladder - Concept of Design

Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
This looks like one of the more user friendly designs that currently exist.
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Sorry, I misread it. I was one line off. The 1/2 x 1 is $10. The 1.5 x 1.5 is $15, just like you saw.
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
Just so you know, I went ahead and ordered a Mast Mate. Not because I have no confidence in building one, but more so time constraints. I am still going ahead with the project to make my own. I have decided on 3/8" rope with 1-1/4" PVC rungs. The rope will pass through the rungs and rest on a figure-eight knot. Also, each rung will have an eye-bolt to attach a sail slug. This will allow the ladder to use the sail track for stability.

Of course, all this hinges on me fixing the outboard. LOL
 
Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
Plan on using Sch. 80 if I can get my hands on it. If not, Sch. 40 is rated at 800#+ for tensile strength. So it should be OK. Thanks for the heads up.
 
Feb 14, 2014
7,418
Hunter 430 Waveland, MS
ated at 800#+ for tensile strength
Unfortunately it is Compressive strength this is the key force. Your weight will bend the pipe in a "U" fashion.
But your rope will be the taking the weight and the pipe will tend to conform to the rope.
So...
No big deal. I would not worry either way about the pipe strength. Schedule 40 will conform easier [meaning the rope will bare weight for the full rung width] and Schedule 80 will probably not BEND at all and perhaps roll more.
Jim...
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Plan on using Sch. 80 if I can get my hands on it. If not, Sch. 40 is rated at 800#+ for tensile strength. So it should be OK. Thanks for the heads up.
Tensile & modulus are two very different things. Google "beam theory" or "beam loading" or "modulus of elasticity" or "beam deflection" for more details.
 
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Feb 17, 2006
5,274
Lancer 27PS MCB Camp Pendleton KF6BL
I did do some reading on the basic three parameters of PVC, tensile, burst, and collapse numbers. I also tested my 12 piece of PVC pipe to see how much it would bend under my full weight. It indeed did bend, but not a great deal. There was also no sign of stress that I could see. Not scientific, I know. I will read some more, but I really believe that 1-1/4" is strong enough.
 
Aug 22, 2017
1,609
Hunter 26.5 West Palm Beach
Engineering:
The fine art of obtaining knowledge by observing the unexpected, after engaging in lengthy & painstaking calculations to predict what was apparently correct, but was actually wrong.

In other words, actually seeing what happens when you try something means more than any predictive calculation ever could. Calculations just give you an idea of what you might want to try.
 
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Oct 19, 2017
7,744
O'Day 19 Littleton, NH
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." -Scott Adams

"Normal people... believe that if it ain't broke, don't fix it. Engineers believe that if it ain't broke, it doesn't have enough features yet." -Scott Adams

- Will (Dragonfly)
 
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Feb 14, 2014
7,418
Hunter 430 Waveland, MS
Engineering
"Nyuk Nyuk Nyuk" " I resemble that remark!" .... Curly Howard [Three Stooges]

Actually Engineers are the mysterious "THEY". Examples..
"THEY made a new bridge"
"THEY built a new car"
"THEY designed a new anchor"
_______
There are many ways to solve a problem, [noted in many discussions in SBO forums].

"The search for "practical" versus "optimum" is a noble quest!" .... JamesG161 SBO member.
Jim...
 
Mar 26, 2011
3,410
Corsair F-24 MK I Deale, MD
As an engineer, I can think of an awful lot of projects I had to get right the first time, using real calculations based, unsurprisingly, on theory. Good, established theory, combined with an engineering knowledge of materials and safety factors.
 
Oct 22, 2014
21,085
CAL 35 Cruiser #21 moored EVERETT WA
When I worked as an engineer, "They" were Sales. "They" designed (promised) what was impractical, if not impossible, and we had to make it happen.
When I worked... I was one of the "They" in sales with an Engineering education, before I declared Business Admin as my major and got a BS at graduation.

Sometimes it was to give the "We" guys a chance to stretch themselves... to achieve the impossible and make it practical.