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Meet the Sloop

March 3, 2010

HDMS Esbern Snare (L17), an Absalon-class command and support ship. Photo by AlexDavClark

New Ships for New Roles

The recent pirate take-down by the Danish naval vessel Absalon, dubbed a Command and Support Ship, gives impetuous to this post concerning warship terminology. New Wars has been trying to get a handle on the ongoing revolution in ship designs, noting the disappearance of traditional types as they take on new roles and new missions in a new era.

For instance, we have detailed the disappearance of the traditional cruiser from the world wars (here, here, and here), with its sole remaining legacy being in numerous small V/STOL carriers in foreign service. Though the term “missile cruiser” still exists in the US Navy, it is really a legacy of the destroyer leaders (also called frigates) from the 1950s, as placing the new surface to air missiles on the large cruiser hull was considered too expensive, especially with stretched naval budgets going mostly for large new supercarriers and expensive and capable nuclear submarines.

So with the destroyer no longer a low cost, easy to construct jack of all trades, but a large carrier escort, the mantle of ASW and general purpose warship fell on the frigate. For the USA, this was a direct descendant of the destroyer/escort from the WW 2, which were built in many hundreds, utilized in all theaters of war with great distinction. In foreign navies, with their declining colonial assets meaning they had less of a need for large fleets, they could spend more time and funds on creating the perfect frigate.

So we see the traditional frigate today has morphed into another exquisite guided missile escort, examples being the Spanish F-100, the British Duke, and especially the older Type 22 Frigates, plus the German Sachsen class. Simultaneously there has also been a trend toward lower cost, but equally large frigates which can perform multi-functions, a “swiss army knife” of warships. This latter seems to be the final evolution of the frigate. Meet the Sloop.

The best definition I can give of the sloop is look at Absalon. According to the Danish Navy, here are the numerous functions in this large but still low cost package:

Main Tasks: Command platform land, air and Naval Forces, transport of personnel and material, military hospital ship or minelayer.

A tall order for any ship, but the Absalon and its often over-looked sister Esbern Snare pulls this off, and at a bargain price of $269 million US, on a 6300 ton hull (full load)! What makes these ship different from say, the average frigate like the American Perry FFG-7, is the large ramp doors to load cargo like an attack transport, or as an APD. In this role we see the sloop’s place in future warfare operating in the Green Water and supporting expeditionary littoral operations “from the sea”.


A Cavalcade of Sloops

While probably the best example, the Danish ship is not the only sloop out there. Ones which come to mind are the C-2 design of the British Future Surface Combatant, the Dutch Holland class, the BMT Venator, and the Austal Multi-Role Vessel. The LCS almost makes this list, except for its high speed and subsequent small fuel capacity. Low endurance is fine for a patrol boat, a fast attack craft, even a corvette, but for the sloop a primary requirement is presence, range, and persistence. The LCS is uncertain whether it is a Streetfighter or frigate, a sloop or a speed boat.

The sloop could easily be a command ship for an Influence Squadron. With corvettes, she could operate like the old destroyers leaders of the World Wars. An ideal function would be leading a force of PCs or assault boats into shallow waters on a anti-pirate or anti smuggling raid. She could be a mothership for coastal submarines. If necessary, she might carry extra fuel to “top off” smaller craft. The sloop would be a far better choice for cooperating with the Coast Guard than Aegis ships or high end frigates!

The following specs are not set in stone (and your criticism and advice is much appreciated), but here are the basics I’d like to see in the Future Sloop:

  • Displacement-3000-6000 tons (less for a catamaran)
  • Length-100-130 meters
  • Draft-3-6 meters
  • Speed- 25 to 30 knots
  • Guns-Lots, mainly small caliber
  • Missiles-point defense and cruise missiles
  • Helicopters-Yes please!
  • Other-Landing craft, RHIB, UAVs, UUVs, USVs, mine sweeping equipment


20 Comments leave one →
  1. JustAnotherDreamer permalink
    May 23, 2011 9:51 pm

    I vote for APD, the Destroyer Escorts modified as fast transports for underwater demolition teams and other small unit deployments during WWII:

    I wonder if the Danes were designing the Absalon class today, would they would use the 155mm AGS, as the reason they selected the 5″ was the promise of ERGM that was recently cancelled? Instead of a maximum of 8 x 4 Harpoon launchers with the Block II/SLAM-ER land attack capable version, I wonder if they’ve considered 4 x 4 Harpoon and 2 x 2 ATACM, the ATACM from a similar-to-the-Harpoon fixed 45 degree launch system that’s been proposed in lieu of the difficulties with NATACM, the naval version of the theater ballistic missile:

  2. CBD permalink
    March 4, 2010 4:01 pm

    The Absalon design doesn’t include much space for serious air defenses. They can hold 5 StanFlex containers in their main flex space.

    The 5 StanFlex spots would be normally filled with 2 AShM modules and possibly 3 ESSM modules. The AShM modules each hold 8 Harpoons. The ESSM modules have the Mk-48DP Mod 3 (according to the manufacturer’s materials and the StanFlex wiki page), which swap 12 ESSM launchers into the place of 6 Sea Sparrow canisters.

    That adds up to 16 Harpoons and 36 ESSM. I think that would qualify it for the ‘G’, with or without the SM-2. If the US were to take it (unlikely), they would probably fill the flex space with Mk 41s. They seem shallow from photos, but since the weapons control systems are stored under the mounts (allowing an extra 2.5m), self defense length Mk 41 modules would readily fit (allowing the SM-2).

    The Huitfeldt Frigates are supposed to bear 32 cells (4, 8 cell modules) of the Mk41 specifically for the SM-2 Block IIIa. What length of the Mk 41 is not usually noted, but many sources seem to indicate that Tomahawks would be possible.* This is in addition to 6 StanFlex spots (I believe 4 of these are amidships). It’s hard to see where, exactly, the Mk 41s fit on most of the available images, but they have been delivered.

    *- This may just be a matter of ignorance. Size matters a lot in what you can carry in the Mk 41 and what you can carry it in:
    Strike-length Launcher : 7.6m/22feet (missiles up to 18.5’) long
    Self Defense Launcher: 5.2m/17feet long

    [Canister: Minimum Mk41 Length (missile)
    Mk 14 Canister: Strike Length (Tomahawk)
    Mk 21 Canister: Strike Length (SM2IV, SM3)
    Mk 15 Canister: Self Defense Length (VLASROC)
    Mk 22 Canister: Self Defense Length (SeaSparrow)
    Mk 25 Quad Pack Canister: Self Defense Length (4, ESSM)
    Mk 13 Canister: Self Defense Length (SM-2II, III)
    Mk 13 (size): Self Defense Length (ATACMs/POLAR concepts)

    This page shows installation, seems to be the Strike Length from the looks of it…

  3. Mike Burleson permalink*
    March 3, 2010 9:52 pm

    Chuck said ““peace cruisers.”

    I can think of no better description of the sloop! We need more peace cruisers in this new era, fewer battleships.

  4. leesea permalink
    March 3, 2010 7:12 pm

    sorry hit the send button too quick. I think what is needed is a warship which is more than a cutter/sloop maybe even more than a PC replacement. Something which will be an alternative to the LCS. Why because I think the LCS will be truncated when the Navy figures out what it can’t do so well and what they really need. USN might end up with two medium sized classes of the corvette/frigate type? who knows? MRV might transcend those two types?

  5. leesea permalink
    March 3, 2010 7:08 pm

    I still think expeditionary frigate is more indicative of the missions intended for a modern ship as described by Mike

  6. Chuck Hill permalink
    March 3, 2010 4:27 pm

    Sloop is both a rig and a warship type.

    Both CSS Alabama and USS Kearsarge were rated “Sloop of War”

    In more modern usage the British used it to denote a ship of frigate or small destroyer size with slower speed but longer endurance and enhanced AAW armament. The Black Swan and modified Black Swan Class Sloops were the most successful class of ASW ship of WWII, 37 ships participating in the sinking of 29 U-boats. The most famous sloop commander was Captain Frederic John Walker. His sloop Starling became one of the most successful submarine hunters, taking part in the sinking of eleven U-boats.

    Ten USCG Cutters given under Lend Lease to the Brits were also rated as sloops.

    The term was also used for what were essentially large gunboats or “peace cruisers.”

  7. elgatoso permalink
    March 3, 2010 4:01 pm

    wiki definition:
    A sloop (from Dutch sloep) is a sail boat with a fore-and-aft rig and a single mast farther forward than the mast of a cutter. A sloop’s fore-triangle is smaller than a cutter’s, and unlike a cutter, a sloop usually bends only one headsail, though this distinction is not definitive; some sloops such as the Friendship Sloop have more than one. Ultimately the position of the mast is the most important factor in determining whether a ship is classified as a sloop

    On a gaff rigged, single masted boat, the clearest distinction between a sloop and a cutter is the run of the forestay. On the sloop, it runs to the outboard end of the bowsprit, which means that the bowsprit must always stay in position and cannot be retracted. On a cutter, the forestay runs to the stem head of the hull. This allows the bowsprit to be run back inboard and stowed. This can be helpful in crowded harbours or when stowing the jib in strong wind conditions

  8. leesea permalink
    March 3, 2010 1:38 pm

    Sloop defnes a sailing rig, not a ship type. IMHO old sailign terms are no longer applicable.

    I like the term expeditionary frigate. That to me means a medium sized warship which is meant to perform different roles from traditional frigates. So like the Absalon class, the Austal MRV and Kiwi Portectors, an expeditionary frigate is NOT meant to be a primary ASW platform (secondary via its helos) nor an strike platform (secondary via its lesser SUW weapons suite, boat and helos). Missiles for self-defense and minor attack sure but that don’t get it a G suffix.

    The big difference to me is that an expeditionay frigate is primarily for EXW missions and large enough to be flexible for those & others. So it would perform missions such as MSO, MIO, naval raids, amphib ops support, HA/DR and other soft power missions.

    The key to me is flexibility and not primarily for Sea Control (caps) or Strike. The “G” should not be in the designation. Maybe call it an FX? OPV might work but that is closer to a USCG cutter? Mmmm what about littoral warfare frigate ? gee that is so close to our least favorite three letters? LOL

  9. Chuck Hill permalink
    March 3, 2010 1:23 pm

    I still like the term frigate for a ship smaller than a destroyer that does classic cruiser functions like sea control. It makes sence because historically the frigate was the original cruiser.

    That does not stop us from being more specific, how about:

    FP, frigate, patrol
    FT, frigate, tender
    FG, frigate, guided missile

    While in the WWII British navy, the sloops like the Black Swan Class were their most successful ASW ships, the designation also reflects a colonial past that has a bad connotation for many people similar to “gun boat.”

  10. B.Smitty permalink
    March 3, 2010 1:14 pm


    Does it get the “G” if it can’t use the Navy’s primary AAW weapon – SM-2?

  11. CBD permalink
    March 3, 2010 1:03 pm

    According to US ship terminology, wouldn’t the Absalon be a Frigate, Transport/Guided Missile (FPG)?

  12. Heretic permalink
    March 3, 2010 12:23 pm

    And I won’t call a 3000+ ton ship an OPV!

    Then what will we call LCS…? ;_;

  13. Jed permalink
    March 3, 2010 10:15 am

    Blimey – as if we don’t have enough problems agreeing on definitions, why dredge up a term from the 17oo’s which was originally used to describe a particular type of fore-and-aft sail rig !

    Admittedly the RN used the term to mean ships smaller than frigates built specifically to patrol for privateers (because “ships of the line” were too big) – so I can see some kind of historical to current context there.

    But Absalon as a Sloop – no, not really, lets stick with modern language like the Danes use to describe it “Multi-role Command and Support Ship” – does’nt trip of the tongue I admit, but if you really, really hate acronyms, call her a “Cruiser” because she has more in common with the days of sail definition of that term :-)

  14. Mike Burleson permalink*
    March 3, 2010 8:48 am

    “Absalon and the MRV would more fit the Joint Support Ship function”

    Wasn’t the JSS concept for the Canadian and Dutch navies for huge ships, like 20,000 tons+? Those might be considered full fledged motherships but it is obvious these are birthing out of the requirement for some type of lower cost frigate, or as Distiller points out “OPV”. But don’t you hate acronyms? And I won’t call a 3000+ ton ship an OPV!

  15. Distiller permalink
    March 3, 2010 6:41 am

    … plus the German Saschen class.
    It’s “Sachsen” class. Means Saxony.

    Naaah. Sloop is just another name for OPV.
    Your 3.000 to 6.000ts sloop is just a frigate.
    Whereby I’d say it’s more 4.000ts and upwards.

  16. March 3, 2010 6:17 am

    I’m not quite understanding your definition here. It would seem that the Absalon and the MRV would more fit the Joint Support Ship function. Even better the Australians properly named Multi Role Vessel would seem the perfect name for this new class.

    Sloop seems iffy. But I like where you’re going. We need a new book of definitions.


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