what does a Lloyds classification mean anyway?.

ok fair enough about all the fiberglass but what about steel--this is my realm of knowedge...does Lloyss or abs approve a sheet of steel|? im hoping im making my point about how difficult this is to figure out?...im guessing steel must have certain scantlings? for a certain type of craft...i.e frame spacing stiffeners etc..steel thickness...

but do they have the same for frp? steel must be classified?

 

Materials, be they wood, steel, aluminum or fiberglass, must be type approved and will exhibit a Lloyd's stamp and certificate. All major equipment, engine , generator, pumps, anchors, windlass, hatches, doors, ports, light fixtures, shaft, rudder, steering gear, etc, must be certified. The manufacturing (build) process must be approved, as must the shop facility, and workers (boat builders) must be certified. The design (structural drawings) must be submitted for approval and will exhibit a Lloyd's stamp. The boat must be built "under survey" by a Lloyd's approved surveyor.

 

yikes!!! (oh and once again Tad- owe you for the info!)- that was very well explained..but holio crap..what a nightmare-no wonder boats in yards sell for so much!..

 

Bored not! More Input. Ya got anything on the use of uni in the layups?

 

very good question! do you overlap at 45 deg angles?

 

about the only thing they wont touch is ferro cement i think !!!

 

if you do overlap at 45/45 you are simply making double bias !!
Its best to draw out what each of the fabrics actually is to get a better understand of the true meaning of glass oriantaion and the way the strands are lay !!. They not just pretty pictures ,follow the dirction of the strands from end to end and get the feel of whats really going on !!

Basics !! All the fabric you see listed for sale are made from uni just stitched together .
As for giving a lay up for uni is never easy because you have to have the drawings and know what you are making and where everything goes and the sizes etc etc .
Uni alone is is giveing you directional strength and and good way to distribute load over a wide area , knowing what the intended use is for what you making has to be well thought out and understood . Most of the fabrics that are out there on the supplyers shelves will cover a very high percentage of uses but befofe you go racing off and cutting glass sit and ponder what you really trying to do !!.
Uni glass is absolutly amazing stuff !! its not completely indestructable but used in differant things it sure can take a lot of punishment and never even show any signs of coming apart , Have seen other glasses that have come off the uni and been riped apart but the uni was still 100% intact and waiting for the next round of beatings .
Used in conjunction with Vinylester resin its mind blowing what achieveable !! ,
Epoxy would be even better !! I have never found any places to want to use epoxies any where . Polyester and vinylester resins have suited all and everything i ever wanted to make . Its much easyer to use and work with and the epoxy smell just about makes me sick thinking about it !!. Its ticky and transfers onto everything , Yuk !!

 

Designers of yachts use uni's to ditrubute loads better throughout a hull !,chain plates to keel and bow to stern under and over the cores and used in conjunction with other Fabrics as well . Keel grids use double bias as the internal tie layer outside then lots layers of uni running every which way inside the moulding then finished off with a double bias again to hold all the bundles of unies in one place . ,
The tops of foam and glass stringers uni gets used a lot , on big jobs 18 layers could get used but thats reall meaty stuff. Making internal Glass frames for boats combinations of double bias or triaxle could be used with unidirectionall glass used inside around the edges of the frames .
In car fenders used Uni glass to make up a edge all round the edge of the fenders so they wouldnt crack and tear .
In the cross beam bases of sailing Catamaran decks uni gets used to carry the twisting racking loads out and along over a wider area so they dont break under exstreme loads .
If you have any woven roving pull out a couple of rows of fibre bundles and wet it with some catalysed resin twist it a little so can hang it and let it go completely hard and cure for 24 hours . Then see how flexable it is !! can tie it in knots !! what you made is whats used on the ends of carbon fishing rods to stop them from breaking off the top 300 mm .
put one end in a vice and pull and see how much pull it takes . Just 2 bundles of stands with resin could support the weight of 3 or even 4 people !! and thats just 2 bundles of strands wet out with polyester resin!! use epoxy resin and its even better !!. The only weakness is bending it over a sharp edge and bending it hard the resin is the weakness not the glass the resin is trying to hold the glass so its shatters !!

 

Thank you Tunnels. Just what I needed Was thinking about using uni's for maybe highjacker pads and gunnel. Have used uni for spar caps on beams with good results.

 

Just be careful laying multi layers of unidirectional glass's one on top of the other ! usually lay a double bias first then 5 layers of uni and another double bias then 5 layers of uni and so on .
Just as a further precaution i always lay a few degrees off straight one way then same the otherway .
Across the uni it possible to split the strands apart !!!
100% of its strength is length ways , so hence the double bias and lay the uni's on top etc etc . even stronger still is to change just a couple of degrees one way and then the other ,plus the double bias every 5th layer ! Always looking for that little bit extra from the glass i use . During all my time glassing i have never had anything break or come apart . Boats i am involved with are just that little bit stronger or a little bit more ridged but never exactly the same as what other people build ,Glassing has never been just a jobs to me !!

 

Tunnels--you need to write a "how to" book on frp/grp layups--there really is a big demand for all that knowledge you have...and i can tell you are passionate about it...!
you have helped many on this thread..thanks!
Doug

 

Each company i worked i have written screeds of information for them .
Now i have quite a bit and when any one asks i have each subject pre-written and been adding photos .
I have a big collection of pictures and photos i have collected over a long period of time as i find the many and varied problems . its absolutly amazing when problems happen theres no one that actually knows what the probable causes are and how to repair them ,more than 90% of gel coat problems are directly related to operator lack of knowledge and understanding also bad habits and work practices .
This problem happens because this is what you did !! ,the operator will look at you blankly !! one of the really biggest problems is workers in general are not interested in there jobs there is no care and attention to detail , All this is very closely followed by the complete lack of understanding of the equipment they are using . They dont know how it works !!
Take a simple spray gun ,you could not believe how many spray painters dont understand how the guns they use every day actually works , i stand and watch and shake my head in total disbelief the things they do to try and get a good even consistant spray pattern .
There is one thing i have learned about spraying that when the needle pulls back and is never in the centre of the hole where the product comes out of the nozzle . even a brand new gun taken out of the box the needle never pulls back exactly in the centre .
I makes the paint come out uneven and off to the side .
one company had a full time gelcaoter and i saw this guy throw his gun against a concrete wall in frustration !! . i walked up to him and told him to walk away and dont look back because he was fired!!,this was the companies seasoned gel coater been doing the job for a few years . So was time to train a new operator right from the very begining , only took less than a week and the young guy completely understood how the gun worked how to dismantal and reassemble the gun blindfolded .what all the setting and knobs were there for and how to get a nice consistant even thickness spray pattern . when equipment works properly and the operator knows what hes doing problems never happen ever!!
later i found a wooden box filled with guns and bits and complete guns used and never cleaned . I ressarected 5 complete binks spray guns for the box all worked 100% so were oiled and wrapped in plastic bags !
The chinese company im at now i made a complete 10 litre pressure pot system using all parts from the junk box of bits . The gun found has a broken hook on the top so they wouldnt use it , itworks perfect and better than the new gun thats always used .
so yes i have a lot already pre written and as new things happen i keep adding to each subject .

 

great! i hope you share it with everyone...

 

Most is written for the guys i work with , This lots was translated into chinese and for the difficult stuf there was even Videos made for the likes of servicing parts of Chopper guns and the operation of !! My translater lady and i spent hours when i first arrived and had to totally strip every nut and washer off every bolt and soak and wire brush clean the 4 guns . plust swap parts off 2 other older guns . because of the exstremes in temparture here inline heaters have to be used during the winter months and even they had to be dismantled and have gelled resin and gel coats dug and soaked out of the channels and flow passages . all this was recorded and written about . . Then came the testing and teaching how to use etc etc