Damage to Aquatimer GST 3536 - 2 questions

Dear Forum
Last July 4th I spent a wonderful day spear fishing in the Gulf of Mexico with 2 of my sons. Great fishing at a moderate 50 - 60 ft depth so we had plenty bottom time. In one of the dives the crown of the watch became undone and had water damage. Question 1 - have you ever experienced this and would you have an opinion what caused it? I suspect fussing with the elastics of the speargun.
I sent to IWC immediately for repair and I am bracing myself for the outcome...I think my Tritium dial and hands will be gone. Also add a full overhaul of the mechanism. Question 2: do you think any other parts will be replaced? The original "fish crown"?
Last, not really an open question, but will I ever dive with this watch again? For sure. It is the best diving watch I have ever had and I expect IWC will repair to base diving conditions. Thank you for any advise, info or commiseration.
Joaquin

Joaquin,
sorry to hear from the damage. But this should be no issue that can not be fixed properly.
Basically a crown does not come loose just by itself. It is very likely that it might not have been wound in firmly enough or that the thread of crown tube suffered from a little debris, a grain of sand, etc. This, in combination with movement against a neoprene suit (or whatever you wear under water), could displace the crown enough to let water enter the case.
Your 3536 still has Tritium hands and a fish crown - has that watch ever had a full service? If not, well, chances are good that this is overdue anyway now. :-)
You can tell IWC to reuse the fish crown if is mechanically still ok. If it is defective, replacing it with a probus crown seems to be the only cure.
As for the hands, I do not know if they can be saved after a contact with water or if water will do some harm to them. It all might be a question of time: how long will those parts be exposed to the humidity. Let´s hope they will open the watch and dry everything right after receiving it.

Very appreciated Jochen.
After looking at possible failure modes, I suspect the thread of the crown was already too worn or damaged, therefore will look to replace with a new one.
I had the watch serviced at a nearby reputable shop in Dayton in the past, being this watch a modified ETA and I wanted to keep the Tritium dial/hands as long as possible. I took it to this shop immediately for drying only, then shipPed to IWC already - I hope - dry enough.
Appreciate your insights, thank you.
Joaquin

Update on water damage to ref 3536
I finally got word from IWC on the extent of the repairs needed. They unfortunately - but logically - are large and expensive. To the point I will not repair this watch. On a positive note, I did love and enjoy diving with it for the years I had it.
As I only used with a NATO strap and endlinks, I do have a fairly new Titanium bracelet (all links) and a OEM rubber strap also seldom used (and the Titanium OEM endlinks). If you are interested please email j_pasquel@yahoo.com as I will no longer use.
If this is message is innappropriate please kindly delete with my apologies.
Joaquin

That's very unfortunate. The 3536 is a legend of a dive watch, too bad it will be chopped for parts. Is it possible to share the info how much you were quoted for repair?

To completely restore the watch, IWC would have estimated for a complete new movement, crown, dial & hands with a maintenance service charge for the work involved. Refinishing the case would be included in this price. Afterwards the watch would be as water-resistant and accurate as the day it was purchased.
Probus crowns were never made for this model so a new fish crown would be fitted.

You are exactly correct. The estimate was for the list you mention. Because these parts are no longer manufactured, some of them would have to be made specifically. The estimated repair is about $3,500 USD.
The dilemma I went through is whether to repair for what I consider to be full replacement cost, or have the opportunity to replace for a different diving watch altogether (and find good use for the parts for someone else).
Thank you all along for the advise.

The last time I had a 3536 serviced by IWC the crown was changed for a probus scafusia one because IWC do (did) not have service replacements with the fish symbol. The old crown with the fish symbol can be refitted, but water resistance cannot be guaranteed.

Hi Joaquin,

I'm sorry to hear about the loss of your 3536. I was wondering if any of the parts you mentioned are still for sale.

Best,
Aseem