Small Combatants - Fast Attack Craft and PT Boats

[ptdockyard]

My line of 1/600 boats has some "What ifs" in kit form:

Italian Hydrofoil MAS


US Higgins 100' PT Destroyer

German VS-10 Hydrofoil S-boot



Dave G
The PT Dockyard
http://www.ptdockyard.com

[icchan]

Related to the idea of tank turrets on ships, I was kicking around a alternate Flower-class ca the 1970s.  Flatten the rear deck and switch out the boats with some RIBs, torpedoes on the sides, and in this particular ship a Centurion Mk. 6 turret forward.  (ZSU-23 to the rear,just because it strikes me as a nasty close-range AA/AS gun).  I'm guesstimating the weight of a Centurion turret at around 13 tons, the question is whether or not the ship can be reinforced to take that kind of recoil energy (105mm L7 cannon) and turret weight.

Dave, that hydrofoil makes me all gooey inside...is that bad?

[Joe C-P]

Related to the idea of tank turrets on ships, I was kicking around a alternate Flower-class ca the 1970s.  Flatten the rear deck and switch out the boats with some RIBs, torpedoes on the sides, and in this particular ship a Centurion Mk. 6 turret forward.  (ZSU-23 to the rear,just because it strikes me as a nasty close-range AA/AS gun).  I'm guesstimating the weight of a Centurion turret at around 13 tons, the question is whether or not the ship can be reinforced to take that kind of recoil energy (105mm L7 cannon) and turret weight.

Dave, that hydrofoil makes me all gooey inside...is that bad?

What's the role of the alternate Flower class? It looks a nice gunboat, what in current parlance is a "littoral warfare" ship.
To lighten the turret one could leave off some of the armour, which would also reduce the effect of recoil as less mass would move when the big gun is fired.
For a US Army ship I built, I chose the "turret" from a SPG rather than a tank, as a 155mm howitzer might work better aboard ship, with the ability to fire at higher angles. For a smaller vessel perhaps a 90 or maybe 105.

[icchan]

Yeah, heavy coastal patrol gunboat.  The idea is a general-purpose "carry a couple torpedoes in case of submarines, have a decent gun onboard, and have some anti-air capability, plus a couple boarding teams" tub...and put it to work doing everything from sea rescue to interdiction to (in packs) littoral combat.

Whiftorically to this ship, originally the forward gun was supposed to be a 3" single forward mount, something like an old QF 12 pdr 12 cwt.  The idea is that it was removed in the 1960s, with an attempt to get a TOW/SAM launcher mounted on it to "modernize" into the missile era, but that never worked out and was removed - and a little creative work by the crew led to the Centurion's turret.  I figure I was going to remove some of the excess bits, cover the coax mount, but I think I can work some on that.  I can definitely see taking off some of the armor, perhaps even getting an earlier model just to match weights, but I wanted the 105mm...

...imagine intercepting pirate sloops with four-inch canister shot...

[Old Wombat]

The original weapons on the Flower class were typically 4" (102mm) naval guns & naval guns tend to be high velocity, high recoil weapons, with limited recoil reduction (that was achieved by ship-roll); so the Flower gun mounts were already pretty beefy. The recoil systems on your average tank would ease that recoil considerably; so you could, conceivably, mount up to about a 120mm/125mm-gunned tank turret on a Flower.

Your other problem with the Flower's is that, unless you swapped out the engines for something more compact & powerful, they could only make steam for about 16 knots - your average Somali pirate could outrun them easily. To fix that, slot in a gas turbine or 2.

Still, it's WhIf-World! Where everything is possible (if not probable)!

[Weaver]

Almost not a whiff: Vickers really were marketing something in the 1960s called the Autonomous Patrol Gun, which was essentially the guts of a Centurion turret (complete with two crew) in a thin naval turret. It was tested by the RN and found to be a very good anti-surface weapon, the intended targets being MTBs/FACs.

[icchan]

Well, the rear deck is getting laid down flat, instead of staying with that arcing design.  Since the originals were running honest to god steam plants; the idea of swapping in some diesels when the stern was rebuilt into a boat deck would do nicely.  And shouldn't be too difficult a swap overall...single shaft, so go simple and make it a single midsize diesel plant.  Or even stick with turbines like a Sleipner...which also does a good job matching her armament.

Any thoughts/critiques on placement of systems, things I should move/delete/add, and such?  I've got a 1/72 Flower on the way, along with a Centurion for the gun turret.  I want to build her up; I just would like it to be as believable a design as possible.

Anyone know if there's good 1/72 naval personnel kits around?  Just for random gomers hanging out, on watch, etc.

[Thiel]

Judging by the following drawings you could probably fit two, or if you want to be fancy, four long stroke diesels in place of the boilers. You'd probably have to rearrange the tanks, but you should have plenty volume available once you remove the steam engines. That'll give you a fair amount of power and the ability to cruise efficiently at no less than four speeds. The main limitation is going to be the gearbox. It should be possible to construct sufficiently powerful gearbox by 1950 or so, so long as all the diesels have the same output at the same rpms.



You've got two ways to arrange them.

The one on the left is somewhat more damage resistant since it has two gearboxes, but in return it'll take up more space and have one more component that can break down.

[icchan]

I'm liking the second. Sans boilers and steam system, it should be light enough to swap in a four diesel array and run a steel slab of two inch plate outside of the gearbox as a bit of a splinter shield.  Doesn't need to be big, just covering where the diesels aren't, and may not even be necessary.

I love the diagram; that's a huge amount of hull space for that boiler.  That's more than enough for a four part Cummins harmony and fuel bunkerage.  I have some work to do to determine how I'll redo the rudder and such to modernize that stern...that seems like a lot of work.  For a country roughly the size and population of France, with a decent chunk of coastline and a major oldschool naval tradition is it too much to do, versus designing and acquiring newer ships?  Or can I get away with declaring budgetary concerns and such required the modifications over time, instead of full upgrades?

[Thiel]

I'm liking the second. Sans boilers and steam system, it should be light enough to swap in a four diesel array and run a steel slab of two inch plate outside of the gearbox as a bit of a splinter shield.  Doesn't need to be big, just covering where the diesels aren't, and may not even be necessary.

I love the diagram; that's a huge amount of hull space for that boiler.  That's more than enough for a four part Cummins harmony and fuel bunkerage.  I have some work to do to determine how I'll redo the rudder and such to modernize that stern...that seems like a lot of work.  For a country roughly the size and population of France, with a decent chunk of coastline and a major oldschool naval tradition is it too much to do, versus designing and acquiring newer ships?  Or can I get away with declaring budgetary concerns and such required the modifications over time, instead of full upgrades?

Ah yes, the venerable Cummins clunkers. (Seriously, I have never run into a four-stroke that noisy before)

[icchan]

Hm.  With three pipes in the funnel, how weird, unworkable, or just plain wrong would a three-diesel arrangement be?  Not like I can't redraw it with four...

[Thiel]

I can think of two options, though I don't think you'll have space for the second one.

Connecting engines via gears is fairly simple as long as they have the same power and run at the same speed.

[Old Wombat]

I'm still thinking gas turbines (as per Oliver Hazard Perry class FFG) would give a better power-to-weight ratio (but I've been known to be wrong in the past).

[Thiel]

I'm still thinking gas turbines (as per Oliver Hazard Perry class FFG) would give a better power-to-weight ratio (but I've been known to be wrong in the past).

They would, but for this refit to make sense it has to happen in the early to mid fifties, meaning first generation gas turbines and an atrocious fuel efficiency.
Diesels give you fuel economy and reliability and when all is said and done, it's still a flower so hull form alone will guarantee that you won't be winning any races.

[icchan]

I admit it's reshaped a little; the drawings at least gave her a new bow with a bit more angle to it.  Whether that's going to last in kit-form, I dunno...but I'm certainly keeping the modded rear end, just because I like the flat deck.