HMS Argonaut (F56) by crabbersnipe - 1/96th - Leander-class frigate

[crabbersnipe]

I thought I'd try my hand at my own full framed and planked model for a change, rather than procure a GRP hull off the shelf. 

Have full a full frames and sheer line drawings for a Leander class GP frigate, and am considering one of the first batch of narrow-beam and gun Leanders, probably in their mid 70's guise.

Am still considering the name of the exact vessel, as I am hesitating between a Variable Depth Sonar ship or not - no two Leanders were alike. I have decided that my model will have a rounded stem, as again, some of the later variants had a straight stem - I would be indebted to anyone who could provide me with a list of ships that fall in either category, as this is only partially documented.

As I have a good set of photographs of HMS Argonaut, I will temporarily dub this build as this vessel, but I may still change the name as I go along.

 

The photographs show the first set of frames, as well as a copy of the ship's plan. I am working off the Jecobin drawings, which are really good.

The frames are cut from 2 mm plywood, but it is clear that the main frames will need to be thicker and am doubling them up so as to get to 3 and 4 mm thickness. I am using the thinner ones a in-between supports along the hull. 

As this model may become R/C, I have also been cutting out the insides of the frames to allow for motors and batteries.

 

This is a bit of a quantum leap in terms of my skills, never having tried a fully planked hull, and especially not one with as may convex and concave lines as a Leander but hey ho, can only fail once :-). Once planked I intend to cover everything with GRP, which will be another first.

 

The goal is to have the hull finished towards the end of winter.

 

Will keep you posted, and will no doubt be asking you forum members for tonnes of advice between now and then !

 

Eric

 

 

 

[TBlack]

Eric,

Whatever your misgivings about tackling this project, it all looks crisp and well done so far. I'm doing a model in 1:96 as well, so I'm interested in your ability to deal with small dimensions. I'll check in from time to time. BTW, forgive my ignorance, but what is GRP?

Tom

[captainbob]

Looks like a good project. 

 

Bob

[crabbersnipe]

Thanks guys, will be good to compare notes.

Tom, I am not too sure but believe GRP stands for Glass Reinforced Plastic, basically fibrecloth drenched in resin and applied as a cloth. Need to do some further research regarding the application, yet another bridge to cross at some point.

 

E

[Omega1234]

Hi Eric

 

These types of modern's warships are always interesting.  I'm definitely following along.

 

All the best.

 

Patrick

[WackoWolf]

I have my chair ready, just waiting on you.

[crabbersnipe]

Did some more work last night and a couple of snapshots to show how I went about the concave frames making up the bow section.

Given the likely problem planking this area, I will be adding extra supports between the three foremost frames, using balsa blocks which I intend to sand to shape before the planking comes on top.

Am using a fairly standard sanding mill together with my Dremel to get the frames in the right shape - quite handy and speedy process really.

 

The bow section is probably the most difficult part of the hull but absolutely critical to get right, as this epitomises the 'elegance' of the Leander class.

 

I am not sure if there are any experts on this platform but have also stumbled into an area that I need to research further; the ship's drawings show two small sonar domes jutting out of the keel, but the commercially available GRP hulls only display one ? Does anyone know what the real ships had, just one or two domes and does anyone have photographs of same ?

 

Thanks a lot

 

E

[captainbob]

I see you have a couple of old "ducks", Were you a ship designer?

 

Bob

[crabbersnipe]

Caught out Bob, funny you should mention it - my dad was a shipbuilder, hence the provenance - you also taught me something, didn't know they were called 'ducks' - very useful piece of kit I find....

[crabbersnipe]

Did a dry-assembly of the various frames on the keel and did some more work on the bows - filling the gaps between the first 3 frames, ready for sanding.

 

On second thoughts, I am now considering building her upside down, as this will make the planking process a lot easier I think. Need to have a ponder on how best to fix the frames so as to ensure a perfect fit with the keelson.

 

E

 

[WackoWolf]

See is going to be big.

[Beef Wellington]

Ooh, very interested to follow along on this one...love the Argonaut, spent a little time in her in the 90's.  Looks like you've got off to a great start with those frames.

Edited October 19, 2016 by Beef Wellington

[crabbersnipe]

Hi Jason,

 

Now there is a coincidence, if ever I need some info on some tiny bit of undocumented kit I will call on you :-) Were you with her in San Carlos

 

Been doing some sanding on the bow section, a lot of dremel and manual work, with a dust cloud to match ! Still not quite there but started to get cramp in my arm....

[crabbersnipe]

Have decided to build the model upside down as this will make planking an easier process. Have therefore inverted all of the frames and installed them upside down on a pedestal, which will vary in length according to the height of the hull for every frame along the length of the waterline. As there is a fractional difference between the depth of the keel viz the waterline I am making allowance for that as well, but especially for the noticeable raised forecastle so typical of the Leanders.

There are really 4 different parts to the hull, two of which fall between the flush deck making up the larger part of the hull starting from the stern on the one hand, and the raised forecastle on the other : one is a very gentle upward slope along the front end of the superstructure and under the gun, the other the 'step' containing the rear set of breakwaters and leading up to the forecastle itself.

 

A lot of calculations and careful fixing followed ! Each of the frames has been attached to a vertical piece of wood, which will then in turn be fixed at a square angle to a bar which will be screwed into the base board at the exact framing spot. The keel and stringers can then be attached thereto once all the frames are in place.

 

I have used nuts and bolts so as to facilitate the removal of the support struts once the hull is fully planked and turned back to normal, before starting on the decks.

 

After that I will be able to start planking the hull, hopefully next weekend if I manage to get a few evenings work in this week !

 

Some photographs to show progress....slow but getting there.

 

E

 

 

[crabbersnipe]

Gave the portside of the bow a final sanding and starting mounting the various frames - quite pleased with the result.

The shape of the bow section is interesting, took me a lot of sanding and checking but  this is the quintessential feature of the Leanders so had to get this right.

 

Started adding the deckstringers and will be completing the remainder tomorrow.

 

Next step will be planking, but will first need to sand the frames to allow for the curvature of the planks and hull - one or two are considerably under size, but this can be remedied and will be adding filling pieces where needed.

 

As will be seen, I have filled up the space between frames 8 and 9 with some pieces of balsa - reason for doing so is that this is the half-way point and since my wood strips are not long enough to cover the entire length of the hull, this part will avoid me having to stop all the planking at the very same point.

 

E

 

 

[crabbersnipe]

Fitted my first plank today, but not before a lot of bevelling on some of the frames, Am generally quite pleased with how most have turned out, but there were still a number which were slightly oversized and causing gaps behind the plank on some of the other frame stations.

 

Tried a number of ways to bevel things quickly and efficiently, and have now come to the conclusion that:

 

- manual sanding is way too slow

- the dremel is quick enough but risks 'skidding' and thus distorting the original frame outline

- started using a chisel in a scraping motion

- finally ended up the paint scraper in the last photograph as probably the best method: sufficient control yet swift enough progress

 

The first plan was laid along the rear section of the hull (the length of the strips I am using not being enough to run the entire length of the hull), using a 4mm wide obechi strip. Will only need to insert a thin piece of wood as additional support on one undersized frame, but that is easy enough.

 

Letting things rest for 24 hrs now to see how smooth the curvature is, where to insert thin wood strips, etc...and then complete the front section.

Have picked the waterline as my first plank datum line, as probably the line with the least distortion or twisting.

 

E

[crabbersnipe]

Gradually continuing the planking. Am thinking of how best to proceed with the fibre glassing once the hull is completed and started doing my internet research.

Bought a fine mesh fibre mat at my local modelbuilder's to give it a try and thought the funnel would be a good start - have started work on this and the idea is to coat this balsa/ plywood structure to see how well this goes, before doing the same on the hull.

 

Must confess this is a bit of a daunting prospect, and notwithstanding a lot of research done so far, still something totally new to me.

 

Am finding rubber bands quite handy to hold the planks together, in combination with the coloured pins which are pushed trough the obechi planks. Progress is steady and have struck up a good rhythm, but am expecting to lose more time as I get nearer the keel. Second photograph (a little blurry) shows where I have added filler pieces, to be sanded to the correct thickness prior to the plank being fixed in place.

 

E

[Jim Lad]

You've made an excellent start Eric.  She's going to look great.

 

John

[crabbersnipe]

Thanks John, so far so good - things will get a little trickier from here on, where I hit all the various curves, twists and bends.

 

E

[crabbersnipe]

A few more planks added and also tried my hand a fibreglassing the funnel - resin took a long time to cure but fully dried out after hrs, will be sanding tomorrow

[Omega1234]

Hi E

 

Nice job. The last photo clearly shows the sleek lines of the hull.

 

Keep up the great work.

 

Cheers

 

Patrick

[crabbersnipe]

Bit of an update, showing progress to date. Partially sanded some bow sections and will clearly need some filler and putty between some of the planks.

Distortion of the planks is still manageable, despite getting nearer to the keel - am considering working 'downwards' from here, using stealers for the remaining gaps. Need to do some more thinking.

E

[crabbersnipe]

Hi forum

 

I will shortly be finishing the planking of my hull and need to start thinking of how best to proceed in term of coating everything with glassfibre cloth.

 

Can I call on some of your experiences on how best to proceed from here ? Some of the questions I have are as follows:

 

- will be sanding and filling the planks

- will I need a primer coat first, before putting on the glassfibre ?

- and if so, should that be 'any' primer or are there specific advantages to using 'car body primers' ?

 

- in terms of glass fibre cloth, I suppose I had best go for the finest woven cloth presumably ?

 

- regarding epoxy resins, does anyone have any experience with the West System product range ?

 

- what would be the recommended 'curing' time for a model of this size, bearing in mind that 

 

* I have never attempted this before and therefore will need sufficient time

* will be doing this in one continuous process, i.e. the entire hull with one piece of cloth

 

Thanks a million for any help you can provide, will be most obliged

 

E

[SailorGreg]

Firstly you have done a great job on the hull.  That flared bow was never going to be easy.

 

Regarding the glass sheathing, I have used products from Easy Composites 

Their 100 gram cloth seems fine for this purpose and their resin comes with slow or fast hardener - I'd go for the slow for what you are doing, it gives you lots of time to play around and avoids that panic as the resin starts to cure before you have quite got everything in place!  Final curing takes 24 hours but are you in a big rush?  Thought not.   (I have used West epoxy as well, which works fine but is a little thicker than the EC resin.  You can thin it a little of course, but I find the EC stuff just right as it comes.)

I would not use a primer.  I think getting the resin and cloth into contact with the wood gives a better bond, but that is just my view. I know others advocate priming (or applying a coat of resin) before glassing.  Each to his own.

I would spend some time smoothing the dry cloth over the hull to get as many creases out as possible,  The weave can distort to accommodate the curves, and some "pre-forming" of the cloth does seem to help avoid the worst of the crinkles and folds.  I use a small foam roller to spread the resin over and into the cloth which doesn't pull the cloth as a brush (or the oft-recommended plastic card) can do.  Here's a hull of mine with a fresh application of the Easy Composites cloth and resin (no connection with the company, just been happy with product and service) -

 

 

It will need another coat or two of resin to fill the weave and to give a reasonable thickness for wet sanding to give a good flat surface, but I hope you can see that even at this stage you get a pretty fair finish.  Good luck and have fun.

 

Greg

[crabbersnipe]

Thanks a lot Greg,

 

Just the sort of advise I needed, there seems to be as many ways of doing this as there are modellers, but there is definitely no substitute for hard-won experience !

It certainly is a slightly daunting prospect but once mastered I think I can imagine myself doing all my hulls myself from here on - it certainly was fun getting this far.

Will have a look at the EC stuff and will keep you posted on my experiences in a few weeks time.

Lovely model by the way, what is it - quite big as well it seem ?

 

Cheers

E

[SailorGreg]

It's a Dumas kit of a Chris Craft runabout. Not really correct to have a picture of a kit on this particular forum, but I haven't quite got to full scratch building yet! It's about 3 feet long.

[Roger Pellett]

Over the past 25 years I have used several gallons of West System epoxy repairing boats for our community sailing association, restoring wood canvas canoes, and building a glued lap strake canoe. I have found the product to be easy to work with and 100% reliable.

 

For glassing your hull you will probably want the longer pot life that you get from the slow cure version, but the resins are interchangeable so if you later have an application for a faster cure all that you have to do is buy the fast cure hardener.

 

Be sure to buy a pair of the correct West System mini pumps. These allow you to dispense resin and hardener in the correct ratio. Mixing resin and catalyst in the correct ratio ensures success.Despite commonly held belief, more hardener is not better! It just means that you will end up with a gooey mess.

 

One criticism of West System is the amine blush that forms on the surface of their cured resin. This can interfere with curing of subsequent coatings. For a small application like yours this will not present a problem as a light sanding will remove it. Something that you will probably want to do anyhow.

 

Roger

[crabbersnipe]

A few more shots - almost there, started planking from the keel down now - also needed to start using nails to keep things in place, the clamps do not have enough grip any more.

 

E

[crabbersnipe]

Thanks for your advice Roger, very useful intel, especially your comment about the pumps and different types of hardeners.

I reckon I will be trying my hand in a week or two. 

Funny you should mention canoe building, was having a browse the other day about doing this plank-on-frame + fibreglassing exercise on a bigger scale and build myself a Canadian canoe !

 

Thanks again,

E

[Roger Pellett]

I have rebuilt four wood canvas canoes. Two Old Towns, a Shell Lake, made in She'll Lake, WI, and one made buy Native Americans near Quebec. All involved replacing broken ribs, planking, and re-covering. I used canvas not fiberglass for this. The worst part of the job is stripping off the old finish and sanding and re-varnishing the inside. The best in show model for NRG's recent contest was one of a wood canvas canoe. See the cover of last spring's journal

 

Roger