Gulfhunter,
I'm an avid water hunter, and in fact, it accounts for about 95% of all my detecting time. About 3 years ago, I purchased the Goldquest SS from Eric Foster and I modified it to be completely submersible. The Aquasearch performance is very similar to the Goldquest (depth/sensitivity). This detector was my only one for these years and I loved it (and still do). Recently, I purchased the Excalibur and I am very happy with this machine, especially with it's iron discrimination. What surprised me was this....in clean, whitish beach sand, the Excalibur was equal to the PI in depth when sniffing out coins and gold rings.....I did extensive/fair tests and just couldn't separate the depth performance between them in the beach conditions described above. I assumed that the Goldquest would leave the Excal behind, especially on gold targets (and probably coins). Now, I also did the same tests on a different beach that has some moderate black sand and here, the Goldquest had maybe a 2" advantage over the Excal. The Goldquest threshold was rock solid, whilst the Excal chatted quite a bit until the sensitivity was reduced to about the 2 o'clock position and thus reducing the depth ability.
As for the recognising iron objects.....the audio never has that pleasing tone....it can sound harsh, irregular and just "too big" relative to the objects true size (especially bottlecaps). The sound of iron is just something that given time, you will come to recognise.
Bottom line for me is this: The Excalibur is equal to my PI in non or low mineralised sand for the detection of non ferrous targets AND the PI will pull ahead when mineralised sands increase and is my detector of choice when I encounter these conditions (always take both with me).
I've never been able to replicate the depths (PI or VLF) that others attest to, such as 20" on a coin or ring. I understand the concept of "halos", etc and acknowledge that my tests are done on freshly buried targets....but then again, in summer, most goodies are freshly dropped, some are picked up quickly, some may sink beyond reach until sands start shifting....but very few have started to really develop much iron leaching. Sorry, digressed a bit.....hope some of this info helps.
One last thing......digging up a coin or ring that is buried past 10" into the sea-bed is very difficult (even in waist deep water)....my test for this was to tie a length of fishing line to a metal washer and mark off the inches with a paint pen....when the 10" "mark" is flush with the top of the seabed, walk away, come back and try to dig the target up......surprisingly difficult and time consuming !!
