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[Crossie]

 So from a slightly vague question about skinning, we've got to where there's someone who's going to try Ron's tights (for size or colour dearie?) and another experimenter who's plans to enjoy a perfectly good slab of beef and then challenge his digestive system by downing not just a glass or two, but six whole bottles of wine! Playing with model boats might be an outdoor hobby- - - -but this way out man

[Nemo]

I am  soooo disappointed Dave! I thought you lived on M'Duck L'orange! Arrrr. 
Bob.

[unbuiltnautilus]

An obscure subject heading, so this is where all the crazy members are hiding? Is that the current HMS Ocean? Would make an imposing subject at that scale, ugly though!

[Stu]

Yes it is the current ocean. I have only seen one and that was in 1:96 so thought it would be interesting.

[unbuiltnautilus]

Yes it is the current ocean. I have only seen one and that was in 1:96 so thought it would be interesting.

And heavy, so it would seem

[ballastanksian]

And heavy, so it would seem

But less than five tons or the displacement of Dave in his car with or without streak and wine (now fish and ale) 

[derekwarner]

Ahrrrrrrrr

The basic premise was correct...[I may invest in a book of trig tables...one on those new fangled slide rules thingies]

HMS Ocean  = 21,500 tonnes displacement
Model scale =  1:72
Model displacement = actual vessel displacement divided by the cube root of the scale
Cubed root of 72 (3√72) = 4.16016764610380729295
21,500 tonnes divided by 4.16 = heavy

However as I originally suggested the term displacement is the key......[I did not invent the use of such a word for ships....]
We also must remember that a ton was originally derived from the TUN which was originally a barrel of Spanish cooking sherry as imported in sailing ships......[eg., a cargo of 100 {TUN} barrels @ 952 litre each + the weight of the ship (2500kg)] =  13 tonne displacement vessel 

HMS Ocean is official listed as 21,500 tonnes displacement however if we were to measure all of the plates & machinery in the construction we may find this to be <8000 tonnes

Anyway...never let it be said that I would throw in a red herring to see if any of you guys were awake on a Sunday evening

Derek

[Crossie]

 Stu, now that we know how big, roughly how heavy, and the general shape of the hull and your construction method, my opinion for what it's worth is to use something like this  http://www.ecfibreglasssupplies.co.uk/p-2345-160g-twill-weave-glass-cloth-1-mtr-wide.aspx 160gsm twill cloth and epoxy, laminating two layers with opposing bias.( a bit like double diagonal planking ) You will then have a very stiff hull well able to deal with it's own mass and the loads generated in rough water/vigorous handling. Follow the instructions precisely for whichever brand of resin that you use and allow to cure well before any further work and the surface skin will be well bonded to the various that the hull is constructed from, will be hard and resist damage well.


      Trevor

[Crossie]

Ahrrrrrrrr

The basic premise was correct...[I may invest in a book of trig tables...one on those new fangled slide rules thingies]

HMS Ocean  = 21,500 tonnes displacement
Model scale =  1:72
Model displacement = actual vessel displacement divided by the cube root of the scale
Cubed root of 72 (3√72) = 4.16016764610380729295




  and if you did, Inertia would probably snap it up, take it home and eat it, so perhaps you ought to throw in one of those barrels of Sherry too! Aharr
22,500 tonnes divided by 4.16 = heavy

However as I originally suggested the term displacement is the key......[I did not invent the use of such a word for ships....]
We also must remember that a ton was originally derived from the TUN which was originally a barrel of Spanish cooking sherry as imported in sailing ships......and little if anything to do with the physical unit of weight/mass

HMS Ocean is official listed as 21,5000 tonnes displacement however if we were to measure all of the plates & machinery in the construction we may find this to be <8000 tonnes

Anyway...never let it be said that I would throw in a red herring to see if any of you guys were awake on a Sunday evening

Derek

 and if you did do that, Inertia would probably snap it up quick, take in home and eat it, so why not chuck in one of those barrels of Sherry for him to wash it down for his experiment, aharr!


 

[BrianB6]

Just out of interest this is what one of our members uses for his 1:100 scale 3 metre long U.S.S. Missouri.

[John W E]

Hi Dave was it a Monkfish? with its heed left on?

serious note, Stu, you are building your hull with a lot of plywood - I am unsure of your experience with resins, polyester and stuff like that - but a lot of people think that by watering down polyester resin with Methylated Spirit is a good thing and allowing the resin to penetrate deeper into timbers and strictly speaking that is not true.  Especially when you are resining over the top of plywood - the resin will only penetrate the first layer of wood - this is because you will have the glue bond which prevents any moisture or resin penetrating deeper into the plywood.  So, in theory, you are only sealing the very first layer of plywood.    What I would suggest you do, on the surface of the plywood - abrade it with coarse sandpaper - something to think about.   Also, although a lot of people can get away with woven roven/cloth it can be a bit of a piglet to work with sometimes and if you are going to use it, I would suggest experimenting first.   But, having said that you may be an A1 class laminator - for all I know - with a Lloyds Certificate.

John

[Stu]

Thanks john al, the info very helpful.
I have given all the ply a good rub down before cutting it but will give it another good going over before resin is applied. Sadly the only A1 I'm good at is the one running from north to south.

[John W E]

Hi ya Stu

Any chance of some pics of your hull build?   Because you have picked a good hull to make - I have just been googling images of HMS Ocean and looking at Jacobin plans on the web and by it is going to be one canny hull to build that one is.   I hate to sort of put another thought in your mind, but, did you ever watch the TV programme 'Supermodels' where they built HMS Invincible and how they made a blue foam core mould?  this might have been an easier answer for you.
Try HMS Fearless (L10) you dipstick john 

https://www.youtube.com/watch?v=hzHB9lWd_Z0

John

[Stu]

I shall try and put some pics up for you in the next few days.
I missed that one on the invincible.

[Crossie]

 Stu , lest you feel daunted by perhaps never having used woven glass cloth before, and some of the heavyweight plain weave fabrics can be very difficult, I really must assure you that medium weight twill weave cloth will go absolutely where you want it to, though the very light 25gsm can be awkward once it has wetted out. Accordingly I have attached a picture of one of my recent and still in progress  projects with a 6" rule for scale, and as you can see it is not very big at all and is most definitely not a simple smooth shape!  This was laid up in two opposing laminations of just two pieces of 90gsm fabric which slightly overlap in the middle. It is very light and strong and was not difficult in any way.
   One tip though, do not brush the resin onto twill cloth, you will tend to drag the weave all over the place, it is much better to stipple the resin into the cloth. It will also be much easier for the inexperienced to drape the cloth over the dry hull, smooth it out until you're happy then apply resin from the centre working equally around outwards.

[John W E]

I am very sorry Crossie but from an A1 class Lloyds Registered person in laminating - who used to laminate RNL lifeboats, your statement is quite wrong about woven roven - we were always taught, and this was by the guys who actually developed resins and the West Systems - cut to shape your matting or woven roven, cutting slots for overlaps and then apply resin mix over the area first, lay the matting over the top of the wet resin and stapple the resin through the matting, ensuring there are no air bubbles and work from the centre out over.  Try and use a ring roller or a corregated steel roller - these are far better for removing air from the laminates.
 
For those who are interested we had to go through strict examinations and test pieces to ensure we could ensure we could maintain the grade.  We had to laminate within, what they call 1;1 or even down further - in other words for every 1 1b of resin used, was 1 lb of matting - that's for woven roven and its 1 1/2 lb of resin to 1 lb matting - you would have to laminate several samples and these would be examined for air bubbles and resin to matt ratios.    You weren't allowed any air bubbles in the main body of your sample.

As a good friend of mine says, suit ones self

[Ron Rees]

Thanks Ballastanksian,
To keep it simple, where weight and ballast is concerned, I always try to build as light as possible, you can always add weight but its very hard to get rid of it if your model weighs the aforesaid 2 Tons...(Nearly as much as my Campervan!!!)


I do actually use some GRP/Cloth/Resin etc and I have also been known to build in wood, but the nylon tights and resin or floor acrylic varnish is so simple, doesn't stink like the inside of a 'Japanese wrestlers jock-strap (That is an old one!)and, once again, if you are worried the hull is not strong enough, and you have some weight allowance to play with, you can still skin the inside/ outside or both with GRP etc.


I think we over-engineer our models, they really don't need to be that strong unless you plan a demolition Derby, marine version. I usually think of the fact that a ship like the Great Eastern had steel plates 1 inch or 25mm thick, on its hull, divide that measurement by the scale of the model, something like 1:100 (for a two ton version) and the scale hull covering thickness should be.........?


Just have fun and build it as nice as you can.


Ron Rees.

[Crossie]

 Bluebird, I will certainly accept your professional Lloyds accreditation and the approved method that you laid out and should I ever build a boat I  would of course, as a former professional engineer, follow whatever method was required to pass professional inspection and approval, especially as it would  most likely be that one would be laminating onto an uncured gelcoat within a female mold with heavy cloth and air entrapment would be a bad thing . My suggestion though was intended to provide for someone who had no experience of using the materials,  a simpler way of  laminating ( which in this case is not the main structural member) over the external hull.  When the surface is wet with resin it might well be very difficult for an inexperienced hand to manipulate lightweight very flexible bias cloth which doesn't slide around very easily without the weave becoming distorted and open, thus loosing strength.
       For what it is worth given that this is a boat forum, working the way that I laid out was certainly an acceptable and approved method when repairing aircraft grp components though of course air entrapment was still not acceptable within the repair area.
Once again, thank you for your correction and guidance, we are never too old to learn.


 Trevor

[John W E]

  put like that come to think of it - it was the most trying, smelly job I have ever done  and in my mind it ranks between a sewer cleaner for the smell    and when I arrived home from work I often felt like I had been down the sewers 

On a more serious note, is, I hate seeing anyone end up with a mess, which I have seen a few times.   A few people have attempted this thinking its fairly straight forward and it hasn't dried, been left with air bubbles, in fact just left with a sticky mess - and to avoid this its good to try and guide folk through the process - in the simplest way possible - and as fool proof as possible - cos working with glass reinforced plastics can be so heart breaking at times.

Good to have a step by step plan in place and a bit of knowledge what can go wrong and what to look for.

Good luck Stu.   Don't forget to throw all the questions you can at this thread.

John

[Stu]

Thanks john, I will have to invest in a ring roller