HMS Havock 1893 - A class Torpedo Boat Destroyer

[Steve D]

6 hours ago, robgizlu said:

everytime I wonder why I even bother with my plastic asemblies

Your plastic assemblies as you call them are miniature works of art Rob. I’ll never be able to paint the way you do. I just saw, file and sand stuff in the hope it works out

 

Cheers

 

Steve

[Courageous]

The usual high class work. Have a good holiday.

 

Stuart

[robgizlu]

17 hours ago, Steve D said:

Your plastic assemblies as you call them are miniature works of art Rob. I’ll never be able to paint the way you do. I just saw, file and sand stuff in the hope it works out

 

Cheers

 

Steve

That is very gracious Steve - but I know where the true artistry lies 

Rob

[Faraway]

19 hours ago, Steve D said:

I just saw, file and sand stuff in the hope it works out

Well in that case, all I can say, is may the gods help us if you ever REALLY try.
Jon

[Steve D]

Back to work.

 

Update on the planking tomorrow, meanwhile, I wanted to get to grips with the shell expansion drawing.  For those unaware, the shell expansion is the plating of a hull laid out flat, so sort of each plate true shape which then bent (normally only one axis) forms the ever changing curve of the hull.  As I plate my hulls in Aluminium, this drawing is key to getting this aspect correct on the model

 

Problem is, they are not common and never shown on model plans.  Havock does not have a shell expansion saved in the IWM archive so it needs to be worked out from rules and logic.

 

So, here I go attempting to explain the rules as I understand them.  

 

In the days of rivetted hulls, hulls were made up from alternating IN and OUT strakes of plating which overlapped horizontally forming stripes on the hull.  There are a few ways plated are jointed to each other

1. Overlapped, used for horizontal joints
2. Butted, used for vertical joints with a backing plate
3. Joggled, can be used for both if that is the pattern adopted.  Grey Fox had horizontal and vertical joggled joints, its quicker to build as the outer strakes don't need packing pieces... getting off the subject

One point often missed out, even on commercial hulls that show rivets, is that all plates are riveted to the frames as well as each other.  There are a lot of rivets on a hull.  Also, butt strapped vertical joints are mostly double rivet lines (each side of the joint), some places they can have as many as 4 rivet lines each side.  In joggled construction, single rivet lines can get used depending on load.

 

So, overall, showing rivet detail on a hull is a nightmare without the shell expansion drawing.  This will show all the rivets and include head sizes.

 

Luckily in this case Havock was flush riveted.  Before turbines, small fast vessels (as this was) were flush riveted to reduce parasite drag.  Once turbines were installed, the power was so much, this no longer mattered and so they left the rivet heads proud to save money.  So, WW1 destroyers all have exposed rivets, as do Flower class corvettes in WW2 as speed was not the main concern, cheapness and speed of construction mattered more.

 

So, we don't care about rivet patterns , but will return to the subject on the deck.  

 

However, we care very much about the shape of the plates.  Luckily, Lyon's book has a tiny shell expansion drawing for a slightly later vessel.  Different size, no bow tube, different stern, but enough to identify the shipyard practice being used for these TBD's

 

Scanning and scaling got me nominal plate sizes ~ 30 inches wide by 140 inches long.  The keel plate looks to be 24 inches wide and the sheer strake is mostly parallel (it not tapering).  7 strakes were used, 4 outer and 3 inner.  Keel and sheer strake are always outer strakes so its always an odd number (tip)  Using the cad programme to measure the curve length on the lines, the maximum half perimeter is just over 200 inches, so that aligns well with 6 x 30 plus 12 when you allow for a 2.5 inch overlap joint between strakes

 

The shape of the hull laid out was drawn by plotting the perimeter distance at each build frame (15 points), at rightangles to the keel line and joining that with a Bezier curve.  Setting a curve 30 inches lower (the stern takes some adjustment and setting a keel plate up 12 inches got me the inner shape to plot (I don't know if this is making sense, but I'll soldier on...).  The keel plate is 24 inches wide so only 12 on each side, it is bent up to shape not joined

 

I then split the remaining distance at each frame in to 5 and joined these points, giving me the nominal strake lines and tapers.  But then the 2.5 overlap has to be incorporated, inner plate go under outer ones of course, so copying up or down does this.

 

Now, the scuttles need to be added as they can't sit on a joint.  They are 9.5 inch down from the sheer line, 6 inch dia.

 

Ok, not the fun starts, working out where the vertical joints go.  There are important rules for this

 

1.  On each side of the hull, there should not be two joints between the same two frames as this creates a weakness, a potential failure line.  If you think about it, 7 strakes, 20 inch frame centres and 140 inch long plates makes this feasible
2. Joints can't be where the condensing water inlet and outflow holes are, nor can they cross the elongated opening for the prop shafts or clash with the scuttles.
3. Joints on adjacent outer and inner strakes should be as far apart as possible, so with a 7 frame pattern, at least 3 frames between adjacent outer strakes (for instance)

So, the problem is an interesting one.  In this case, a few rules needed banding as the scuttles don't comply with the 7 frame spacing, due to internal constraints.   Never model riveted joints in a simple brick pattern .... Welded hulls are different as the weld should be stronger than the plate so these considerations don't matter.

 

After much juggling, I'm OK with this result which complies in general and has the least number of broken rules.  See if you can spot the rule breaks....

 

 

The pale green lines are the actual hull frame centres, 20 inch all the way along

 

Note the very large elliptical opening for the condensing water intake, which I bat on about being missing from almost every model.  The sections on the as-build plan show the pipework so I could work out exactly where this is.  The round hole higher up and rearwards is the outlet.  You can't run a steam plant at sea without a lot of condensing water cos you can't boil seawater and expect to go far....

 

In this case, both sides are identical (apart from the crew heads outlet, starboard side only).  This is not always the case, plating often varies side to side (also scuttle positions) but the example in Lyon's book is identical which is great.  Also, this canoe hull has strakes running the full length, in model larger vessels this is not the case, additional strakes are inserted to create the bilge with a triangular plate joint detail

 

I've now probably lost the room, so I'll stop here.  Please hand in your papers when finished 

 

Planking update tomorrow with not more naval architecture lectures.  

 

Cheers

 

Steve

 

[foeth]

Ah yes, that nigh imperceptible difference between “that looks about right” and “it must make sense”! Keep piling on the lessons…

[Iceman 29]

 

[Dmitriy1967]

It seems now I know how to build riveted ship hulls. It seems. Maybe... Most likely... But I'm not sure... 

In short, it was written damn clearly!

But I understand the theory better when I do it with my own hands. 🙂

 

I just now thought that the riveted hulls of the ships had to flow through numerous joints and rivet holes. During the installation of the plates, were the joints smeared with some kind of sealing compound?

[Steve D]

3 hours ago, Dmitriy1967 said:

During the installation of the plates, were the joints smeared with some kind of sealing compound

Rather than write another essay, below is an extract from Practical Ship Construction by Carmichael 1919.  This  explains how joints and rivets were "calked" to prevent leakage

 

 

Interestingly, my copy of this book is marked as once belonging to the library aboard USS Boise (CL-47), a light cruise of the Booklyn class launched in 1936

 

 

Just sharing

 

Cheers

 

Steve

[robgizlu]

( I laughed at losing the room)

Rob

[foeth]

12 hours ago, Steve D said:

 

 

Interestingly, my copy of this book is marked as once belonging to the library aboard USS Boise (CL-47), a light cruise of the Booklyn class launched in 1936

That would explain why the plates were not caulked? 🤔

[Steve D]

9 hours ago, foeth said:

That would explain why the plates were not caulked? 🤔

[Steve D]

Not really much to say about planking once you start, you keep going until there are no gaps left, tapering the planks as necessary, all a bit boring really..

 

 

Approaching the bilge, I inserted a 4mm wide plank across the main point of curvature

 

 

 

This curve was too tight for the 6mm planks I'm using and placing it there gave me two easier segments to complete, worked OK in the end

 

Done, with the second of three rounds of wood filler to ease the hollows and smooth the plank edge alignment (1mm really is too thin for this job...)

 

 

 

There is quite a pronounced belly in the centre, still really its a canoe

 

The stern needed my usual jelutong blocks added, seen here roughly shaped.  Note the tube for the rudder lower hinge.  The rudder lifts up into this tube and then is anchored and hung from the top hinge, more on that later

 

 

Some time later

 

 

The exact shape of that lower inner edge is unclear, I've left is crisp at this stage and will sort it out once I try to make the plating work.  Note, I added some 2 part wood filler to ensure a blemish-free join

 

So, the hull is made and ready to plate, with a light coat of matt acrylic varnish applied to seal the surface to help adhesion of the plating glue

 

 

I was really lucky with the wood order this time, the lime is very fine and nice, it's not always the case.   

 

On to metal now 

 

Cheers

 

Steve

[Dmitriy1967]

This ship has a very elegant hull.

Your work, as always admires!

[Thom216]

Lovely, classical lines!

[Old Man]

A privilege to watch this brought into being, Sir.

[Steve D]

On 20/09/2023 at 21:36, Dmitriy1967 said:

Your work, as always admires

Thanks Dmitiry, I'm doing my best to do it justice.  The hull is paper thin after sanding, the metal plating is needed to firm things up.  Should have used 1.5 mm, lesson learnt

 

11 hours ago, Old Man said:

A privilege to watch this brought into being

The privilege of sharing my few successes and many failures is all mine. 

By showing these techniques, I hope others can be inspired to return to more traditional model ship materials

 

Cheers

 

Steve

[theskits62]

Beautiful work, very much looking forward to seeing the process for metal plating.

[Iceman 29]

Beautiful hull and workmanship, Steve! 

 

The weather is bad, that's good for us! 🤪

Can't wait to see what happens next, like the others...  

[Steve D]

Short update on the plating.  Really not much to say, it is a steady job as the saying goes, each plate is cut to size, most are trapezoidal, 4 sides not equal or even necessarily parallel (think that's a trapezoid )

 

Anyway, the process starts with marking out the lines of the edges of the inner plating strakes.  I used stretch flexible line marking tape sold for cars, and kept adjusting it until it seemed about right.  This took quite a while

 

That thing behind the ship is an attempt at the buck for the armoured deck house that the bow gun sits on.  It's slightly wrong, I will make a better one

 

 

They don't look even because I worked from both the keel and the sheer line and so the side that is the edge of the inner plating changed.  Don't worry, that's probably really confusing statement

 

Anyway, I then used a Sharpie to mark the plating edges.  The problem with using pencil is it tends to get wiped on with handling, the Sharpie doesn't.  It looks a little crude here, but it will do

 

Here is the beginning of the uppermost inner plating line

 

 

Both these edges get covered by the outer plating runs so its not too critical.  For this job I'm using Aluminium sheet, 0.1 mm for the inner rows and 0.2 mm thick for the outer rows. This cuts easily with a sharp knife, but the 0.1 mm thick sheet is really easily damaged when handling so be careful.   You can buy this from 4D model shop among other places.  The plates are stuck to the wooden hull using Gorilla Superglue, the brush applicator version which makes it easy to exactly paint the areas of the plate.  Mostly there is either no curvature or single curvature only.  The rear of the bilge keel inner row has some slight double curves, but tape holds is down enough to settle into the right shape while the glue hardens.

 

More or less all the plates are either 6 or 7 frames long, so 120 or 140 inches, there are a few exceptions but all plates are a whole number of rows long.  The only challenge is not getting confused regarding where you are, I do that often these days.  Once stuck the surface is cleaned using a scotch pad.  This takes the shine away and removes any glue that seeped out.  It also leaves the surface perfect for priming.

 

Starting the sheer line outer, all the same width until very near the stern.  This has been cut around the bow tube

 

 

It always amazes me that more or less flat trapezoid plates form such subtle curves.  Above you can see that the inner lines are wider than the outer.  Obviously the outer lap over the inner and as I only marked the inner, this is the effect you get.  In fact, the inners are slightly narrower mostly, though not in the round of the bilge which is an inner line

 

Second line complete, I will do the stern once both sides are complete

 

 

Last detail is the condenser water intake which is a 9 inch pipe at ~ 20 degrees, so a long ellipse.  I cut a short brass tube to the angle, epoxied it in place and then plated over it and opened it up.  This hole will be covered by an etched brass grating later.

 

 

So, not much more to say, this job will take me a few days to complete, but its all the same repetition so I'll post some more pictures once this stage is complete.  The butt joints will almost completely disappear as this is flush riveted.  However, the key word there is "also", when you look closely, you will be able to see them and that is the whole point of all this effort.  Plus having the plates the right shape, means the process will work because it did on the real ship.  The other point about using metal is it inevitably takes a little slight damage no matter how careful I am.  Rather than worry about this, I like the realism this slightly knocked appearance provides.

 

Cheers

 

Steve

[theskits62]

32 minutes ago, Steve D said:

Both these edges get covered by the outer plating runs so its not too critical.  For this job I'm using Aluminium sheet, 0.1 mm for the inner rows and 0.2 mm thick for the outer rows.

Hi Steve, slightly confused, if you're using thicker metal for the outer strakes why do you have an overlap with the inners ? I could understand using the same thickness of metal for all the plates and using spacers to push out the outer strakes so you can have an overlap or using different thicknesses for outer and  inner as you are doing and then simply butting adjacent plates against each other. Thanks

[Steve D]

20 minutes ago, theskits62 said:

slightly confused,

Such a good question.  It stopped me and made me think.

 

Here are 5 reasons for doing it this way

1. The plates overlap at full scale, so my inclination is to do the same
2. The outer plate @ .2mm is 1/2 inch at full scale, seems about right and even if not, it looks right
3. By overlapping the plates, I can be less precise than I would need to be if I butted them together. Remember, the plates have mostly straight edges but the butt ends are not at right angles to both sides of the join.  If I had to butt the plates longitudinally, I would need to cut these slight altered angles into the long edge, and I'm not good enough to do that right.  Slight gaps in the join will show up very much and really can't be filled. 
4. By overlapping the plates, I don't have the gap problem and it holds the edges of the thinner plates down which have a habit of catching and lifting.  The thicker plates don't do this as they are stronger
5. The overlap lifts the outer plate a tiny amount and this evens the finish of the hull making slight blemishes in the wood invisible

So, at 1:48th I know this works.  If I were working at 1:96th, I'd ignore the inner plating altogether and just apply the outer strakes

 

Hope that helps explain things

 

Cheers

 

Steve

[Andreas.R]

Hallo Steve,

 

here maybe a link with interesting historical background: https://steelnavy.net/CombrigHavock700.html

 

cheers 

Andreas

[Steve D]

22 hours ago, Andreas.R said:

here maybe a link with interesting historical background:

Thanks Andreas, I had found that link.  Here is my cleaned up copy of that picture, probably the best close-up I have

 

[Steve D]

Plating is boring so here is a little woodwork (actually the last woodwork on this ship), the buck for the armoured bridge, heads and focsle gun mount.  This is actually quite a complex shape as it merges the turtleback with the deck wings.

 

Lots of fun drawing it out and then cutting (I'm getting so lazy wiht this xtool) main frame in 2 mm ply

 

 

Frame assembled

 

 

 

Both pictures of version 1, wasn't quite right, version 3 finally came up to scratch.  For such a small object there are a lot of things to consider

 

The heads are either side of the roundhouse, sticking out with rounded corners

 

 

Then the turtleback faired in using 3 mm x  1 mm lime

 

 

 

This is removable still to help me work the copper that will form the surface and the curving wings down to the side gun enclosures, see picture on previous post.

 

Lastly the top is turned from 2 mm ply in a dome shape, that will also be covered in copper.  The 12 pdr gun mount site on the top of this dome, hence the flat area

 

 

Seems OK, back to plating....

 

Cheers

 

Steve