can you decrease plate thickness or use FC for a tug?

great--finally!

 

O.k Richard- good luck to you...

 

soren--(Im holding back my laugh here)- the posts for frames and stations was years ago...also- the complexity of the plans would challenge anyone to understand the way to loft these plans unless they were very experienced builders or NA's. Ive looked at hundreds of plans over my life--and none as complex...so 'scuse me if i needed to verify how to get the frames from the stations --i knw the diff between stations and frames..just not how to loft them since i have never lofted anything like this..

 

I must say, this has been highly entertaining to read, but sadly a-typical of those that come armed with preconceived ideas and wont be change, no matter what.

So, you have restricted anyone’s answer to one that fits into what you want, ferro-cement. It is clear you won’t entertain any comments that do not align with this, from your statement above.

Nowt wrong with that, but in order to understand any material for any application, one must know all the good points and bad points before embarking on the design. So an advocate is hardly going to inform you of negatives, only positives, thus falling in your preconceived notations before you started the thread.

As has been pointed out by many on this thread, you do not want to hear detractors only positives. Well, that’s fine, but it will get you know where fast. One must always design for the worse case scenario, whatever that may be…yet you have elected to design or hear only about the easy scenarios that fit your ambitions. I can’t say budget because you maintain there is enough money….

To make matters worse, you’re trying to invent scenarios to support your ‘theories’

Is that so?

So, if I press with my finger, very hard, on a coin against steel, it will puncture easily will it?

The only person I can read here that is threatened is you. Your much cherish beliefs and love of all things FC are challenged, your design experience is being challenged, your knowledge on tugs and the environment that operate in, is being challenged and so on.

You have not supported any of your beliefs or ‘technical’ arguments with facts. So if you are unwilling to listen to others providing you with very sound valuable advice, why bother asking in the first place:?:

 

ok Ad hoc what positive advice do you have for me--?? believe me im secure in my knowedge--ive succeeded where people said id fail..many times...I have never been an NA so i cannot arugue on theside of convention--what i cna say is what i feel see touch and know to be strong. I dont care about textbook methods..what s worked for people much longer than textbooks and math is intuitive design. Those people already have said they are done--great! I think ive leaned enough at this point anyway ...what ive learned is--to believe in my self--not others opinions. unless it has practical use--
why do you sya I dont listen to them..so for you--i am supposed to just agree with everything anyone says--like religion?..what makes them any more qualified to berate my ideas? instead of people adding to solutions they choose to tell me to do it thier way or ill fail--but they cant know that...so for people who have nothing positive to offer, i ignore it...as would you...people on here make a a lot of hilarious and absurd assumptions about me...
you assume i dont knwo the bad points about fc ..or about steel??? ok let me inform you what i know is bad about it--
fc- prone to cracks, uh brittleness, heavy - strength to wieght ratio low. Its difficult for one person...theres many more but you et the idea...what else is there to know--im a grown up and i know the risks. right now i think im reayd to build..i suppsoe i dont need much else from this thread or forum...

btw--steel is easily holed--thats no theory..just ask great lakes tugboat skippers how easily they will tell you....ill repeat there is no perfect material...so why do people insist on saying one is better than another..and belittle my choices?

 

I am absolutely astounded by statements like this. It shows how much you value professional opinion and the whole profession of Naval Achitecture. Zip, Nodda, Zero! It must be that you don't have enough knowledge to even see what you are missing. The fact that you are guessing, relying on dubious formulas and false similitudes instead of using the design spiral is telling.

You are unlikely to get much of anything except negative indirect answers to your questions because of the way you are aking your questions. Your question format is very similar to asking an inocent man a question like " So, where did you go after you beat your wife?" I would not expect a direct answer or a positive response from the man to a question like this. When you take out the false assumptions from your questions you will get a much more positive result.

You seem very offended when others call out those false assumptions and try to get you to re-phrase your question in such a way that a direct answer can be given.

 

Well tugboat, this is the crux of your problem:

Your whole MO is based upon your belief, faith of what is palpable to you and you alone. This MO has nothing to do with facts, validation, verification, science and normal qualititative engineering. Without paying any due regard to such “basics”, your opinions are just that, opinions, which have no supporting independent factual evidence. As such, no matter what anyone says, if it does not align with your beliefs you will not listen or accept it. There is no learning process going on you’re just stating your opinions, that is all.

Hence, who is it your trying to convince with regards to your MO and knowledge/expertise, …us….., or yourself?

 

to adhoc and Pierre r,
1: I design boats that have worked before- using traditional methods used prior to autocad etc.
2. designs have become overly-complexified(my opinion take it or leave it!)
3. because of this- to gain an extra half knot of speed or to insure a small advantage in stability - the equations and formulae are so complex that no one other than an NA is considered "qualified"
does this mean the layman cant pick up a good book learn the "basics" and then design a functional design? and besides--my 45 ft design was done by an NA.
no one yet on here has produced a solid "fact based" opinion on why fer-a-lite wont work ? -BOTH OF YOU NEED TO REREAD MY THREAD if you dont get that...
as far as my MO being based on faith etc--so- the numbers game is the same faith different religion!...they are just thoeries as much as my methods are based on theories. if you dont agree go study some epistomology...

albeit those theoretical ways of doing the numbers game- are more widely accepted and tried out. but doing the math doesnt guarantee results any more than my way of making a half hull, looking at the lines -following some basic scantlings and rules and testing it in the tub....the only truth- is if the boats floating and behaving accordingly or not...and no i wont listen to others negative drivel trying to get convince me of certain failure or a certain definitive way...

after all people choose one material and usually stay with it for life cuz it becomes familiar to them...
and when they dont get me to bow down to thier authority on the matter -as noted in thier posts- they start to try to use other means of control i.e accusations, insults and character assasination in order to control the outcome to get me to believe they are all experts and only thier way will work-so please excuse me when i show that a lack of respect!... and then they storm off like little children because they couldnt get thier way this is funny to me! ive seen this many times on other threads too...and its always the same old people doing the same old ********..

if my responses bother anyone--guess who's issue it really is? im a fair person but i wont be the subject to negative redicule and will defend myself ,..

the responses from CERTAIN individuals, not all, were quite inappropriate.
and lets get something really clear here-
these certain ones- in my perception- are not calling me out trying to get me to rephrase my questions- if thats the case--they would have said to me: "please rephrase your question to this particular parameter" etc...but i dont see those words anywhere on this thread... and I actually do know the basics of design and a bit of naval arch myself--here what i do:

start out with a sketch- check the block co-efficents- modulus of elasticity to a known material if i can find the constant- i then check wetted surface area- use simpsons mulitpliers, then work out LCG COE COG RM set up a DWL and LWL CL etc etc--i would say those are pretty basic...just cuz i dont agree --dosnt mean I dont respect what they are saying..what i have an issue with is people telling me they seem to know my business and financial situation and make huge idiotic assumptions about me...you may not want to hear this -but theres a good chance everything will work out just fine with my methods ..and if this happens -then the question has to get asked by NA's " how is it he can succeed when i need to do massive calcs and use autocad-- or why did i go to school and spend all that money when he can do the same thing without that education?...this is why they need to accuse etc. if others succeed without the degree-then everything ive learned is unimportant and that means I am expendable and not needed and i may be out of a job --of course this is an unfounded fear -

my design will function reasonably as i mentioned in this thread--like it or not ..it will...i do need some help here and there. but I have factual evidence- my boats worked..what more do you need? what i need help with is specifics answers-such as can i decrease pate thickness or how thick can i get away with on my personal design--and to this I have recieved answers/statements such as --"ohh you will regret that' or Im making things up to fit the Parameters (and dont believe me if you like or go do some tests on what i say but dont accuse me without facts either!! hypocrites!)"

which are not facts either and therefore just as valid or invalid as my "methodology"

 

"So, if I press with my finger, very hard, on a coin against steel, it will puncture easily will it?"

answer: yes-if that finger has the force behind it of a 20 000 lb vessel in steel running at 8 knots and your finger doesnt break before its punctured...

 

And what is the thickness of said plate?

 

No, sorry I was completely wrong with my opinion about you!
You are just another idiot who likes to get his bias confirmed by professionals, nothing else.

 

Don't confuse TOUGHNESS with STRENGTH. You could build a very tough boat out of chicken mesh and Sikaflex, but it's strength would be abysmal.

 

Yes John there's a lot of completely meaningless numbers being produced as material properties But if you read the blurb they basically build a wire mould then laydown a layer of fibreglass then trowel on the goo then use car body filler to fair the goo and seal the mesh inside. There's no lab material testing no immersion properties data, no temperature data no panel properties, just we built some this way and the ones still around are mostly ok. The ones that aren't around we don't know about.

No real design guides. It's all a bit shy of factual data. Cost weight strength durability and construction time tradeoffs comparissons just can't be made.

 

Here is one copy of a lab test that was performed in 1973.

 

Interesting. The figure quoted is very similar to the one in this report 62MPa to 57MPa.

What is intesresting in this report is that FC would not pass an ISO "standard Fire Test".

Apart from the obvious that it is not steel, the rise in temp is a concern on the unexposed face and also the it would not prevent the passage of smoke, owing to the cracks.

So, you would have to insulate it, and have a smoke barrier too....one may wonder why then, that this is not the "ideal" material for boats!