We don't need a maritime / amphibious Brigade. It's questionable if we even need 2 RAR as it is, but who am I to question removing a unit....
The vast majority of landings conducted, ever, have been done with regular Army units. Read Kainmbla's war diary from 1944/45; the majority of units she takes are Army units - some of who Kanimbla is the first time they have seen a boat, landing craft or ship. They do rehearsals along the way. Aphibious is just another dlievery method.
Also, people really need to understand Beersheba / Keogh. They are raise-train-sustain organisations, not warfighting organisations. The Brigade we need will be assembled from 1 / 3 / 6 / 7 / 16 / 17 and others with the C2 element drawn from 1 / 3 / 7. This means that any of our units needs to be able to conduct amphibious operations (emphasised by our region). So a marine Bde would actually undermine our overall flexibility and capability (especially as, generally speaking, marine units are not as capable as land focused units).
Strike one against an amphibious AFV.
With this in mind, it flows that the forces do not need to be amphibious - rather the "bits" that move forces from the ships to the land need to be capable. They need to be able to carry lots and quickly. But they are fundamentally simple, and hence cheap to upgrade as technology increases. It is easier to upgrade a ship-to-shore connector (despite the ADFs best attempts to do otherwise) than an entire AFV or land mobility capability. Fundamentally, a ship-to-shore connector is more flexible than an amphibious vehicle, as it can move more "stuff" in a given period of time. The amphib can swim ashore (yay!), the landing craft can move a better vehicle, then do all it's stores and support in wave 2, 3 and 4.
Strike two against an amphibious AFV.
Now, tactically we need to move from the ship to the land as fast as possible. It either gets more stuff ashore, or allows us to strike from over the horizon and hence keep the ships safer. Amphib vehicles will never move fast. K-21 speed = 3.8 kt; LCM-8 = 9 kts. More than twice as fast. And LCM-8's are slow. LCM-1E go 50% faster again. And if we want to go crazy, a LCAC is 40+ kt. They are all exemplars - but anything that is a displacement hull (which an AFV is the best example of) is slower than other options like planning or hovercraft.
Strike three against an amphibious AFV.
"But Boxer is too big" I hear the cry. "It can't deploy as well". Noting that protection drives size, pending a change in armour technology or better integration of unmanned elements, all AFVs are going to be about the same size for a given protection level. But an amphib needs even more space for flotation. So pick one, an amphib has to be less protected (despite facing the same threats) or bigger (with consequences for tactical movement and deployment in confined areas like a LHD or C-17).
Strike four against an amphibious AFV.
Finally, the cost. We plan on running five 'armoured' fleets: Hawkei, Bushmaster, Boxer, IFV and M-1. They are in addition to three B-vehicle fleets. These things are expensive, and we want to add a sixth? "But it'll be smaller and cost less" I hear. You need a minimum fleet size, look at M-1. So your 40 may not be enough. So your sustainment costs will either be higher, or you cut the other fleets.
Strike five against an amphibious AFV.
tldr: Purchasing an amphib AFV goes against historical knowledge, reduces tactical, operational and strategic flexibility, undermines the basis of the Australian Army's structure, is too big, costs too much and will struggle on the battlefield, taking more losses.
Overall, it's a great example of kit fetish over needs analysis.
Point 1 regarding a dedicated marine BDE - I agree, we simply don't have the manpower.
Point 2, I also agree. However a SSC can not move vehicles through all littoral environments (i.e. Reef, submerged sand bank). Additionally the vehicles you mentioned are all wheeled, with the exception of the IFV which will be large and weigh a considerable amount - too much to be an effective ATV. That is why I used the Goanna as an example - a lighter tracked vehicle able to penetrate poor littoral environments and capable of navigating narrow jungle tracks better than a CRV or IFV.
Point 3 I agree with, the Goanna (and other amphib vehicles) are slow. However it can also be deployed at more tide levels and into "brown water" environments. I agree it is an issue, but not enough to dismiss it. That being I also did not recommend the vehicle in a non-permissive environment, directing it more towards "volatile" contingencies in the South Pacific or Timor-Leste. An ARE can be deployed with an engineer support force with protection provided by Goanna and the PLF security PL - not requiring a dedicated combatant element from the ARE. This is an example.
Point 4 on protection. The BvS10 and Bronco have been used on deployments in Afghanistan and Somaliland, both hostile areas of operations. Whilst not ideal their protection levels can be improved with addon armour, counter-IED technology and RWS. IEDs can be used in any threat environment sure, but there are ways to counter this. As evidenced by the several nations who use it (including the British in Afghanistan), it is not a deal breaker. Whilst not the Goanna, I'd take a look at the Bronco 3 and it's respective upgrades to enhance protection.
Point 5 is maintenance and sustainment. I honestly don't know how defence plans to maintain all these major land fleets over the coming decades, particularly with a developing local supply chain. However defence seems quite alright with at least considering the prospects with such a vehicle, indicating they are at least open to the procurement of these systems and their continued maintenance.
It is worth noting that defence only considered this as a sort of optional extra as part of the RFT for Land 400 Phase 3. I agree it is a nicety, but I also agree it has flaws.
As noted in the pdf provided by t68, there is at least some greater level of mobility with regards to the Goanna as well as merit to the future replacement of the LARC-V (an unprotected, amphibious logistic vehicle).
https://www.baesystems.com/en/download-en/20151109141738/1434554723012.pdf
I never advocated for giving up the use of CRV or IFV. Like I said I see it only in a low-intensity environment where guerrilla, insurgent, criminal or militia groups can operate - their potential in Timor-Leste, PNG, Bougainville, the Solomon Islands or Vanuatu something worth considering in addition to the terrain and littorals.
And when I say I how I "feel" regarding the choice, I did lay out why - even if basic. I did not advocate for giving up IFV or CRV and I agree maintenance costs could be an issue, but not a deciding factor - as with protection.
It isn't perfect, but I see it's uses in a low-end assymetrical environment. My main point was that the Goanna has key merits and value that can make it an asset, not that it is an ideal platform for the ADF. I can see how it may have been seen that way.
To summarise I disagree with the suggestion amphibious vehicles are of little to no use. Yes IFV and CRV are better in nearly everyway, but they are heavy vehicles designed for a high threat environment - their threat environment drives their protection level. This is the same with the PMV and PMV-L, again a low to mid-end environment with limited protection.
I see the Goanna as a niche, low-end role. Regardless I stand by my point.
