A couple of very interesting videos of clever ideas that work together and might have Coast Guard applications.
First there is this little tracked amphibious truck, which can be launched from and climb back onto the catamaran work boat in the second video. Looks like these might have application in maintaining aids to navigation in rivers, deltas, shallow water, marshes, and possibly over snow and ice.
They might also come in handy during floods and for occasional atypical SAR cases.
Thanks to Lee for bringing these to my attention; I’m pretty sure he saw them at http://www.thinkdefence.co.uk/
Chuck Hill's CG Blog 
Hi Chuck, didn’t realise you had your own blog, will do a link to article if thats OK?
Anyway, the piece in question was here
http://www.thinkdefence.co.uk/2012/08/innovation-in-the-littoral/
Not so fast.
Its a chinese 8-wheeled (or 6-wheeled) ATV and the UK just cut the bottom out of a small boat and dropped it over the ATV.
http://markc.en.china.cn/selling-leads/img_1001667270_1.html
Heres another: http://www.alibaba.com/product-gs/234449369/Amphibious_jet_boat.html
Not so fast.
The cut the bottom out of a boat and dropped it on an ATV.
Its Chinese.
both 8 and 6 wheeled:
http://www.alibaba.com/product-gs/234449369/Amphibious_jet_boat.html
Whole page of them here: http://www.alibaba.com/showroom/8-wheel-amphibious-atv.html
There are a number of 6×6 and 8×8 ATV’s on the market so who knows what the donor vehicle was
Have a look here
http://www.argocat.com/argohistory.html
Yes I sent Chuck the link from TD. Really like that website!
From a cutter viewpoint, the use of tracks + wheels allows the craft to board the mothership quickly and without a built in stern ramp. I wonder if those ramps could be fitted to other cutters?
From an operational viewpoint, like Chuck says in in shallow water or wet land area, it could have distinct advantages.
I see these as primarily useful on our river tenders and inland waterways.
The Coast Guard in cooperation with the Corp of Engineers is supposed to be developing a new class of inland tenders. Maybe they could use a boat like this.
Apparently the CG is looking at and amphib for the Arctic:
http://www.alaskadispatch.com/article/coast-guard-eyes-all-terrain-vehicles-take-arctic-ocean