If anybody ever does get water in a coil that isn't epoxy filled, chances are you can save it. Just let the thing dry out real well in the sun, and after that if you want to be double sure then stick it in a bag of rice to soak up any more microscopic moisture before sealing it again. I'd probably spray any electrical stuff inside the coil after it's dry with a electrical cleaner that has a anti-rust compond in it to prevent rust or oxide build up. Be careful the stuff doesn't take the varnish off your coil windings as if they aren't insulated with the varnish they'll short to each other. In fact, I'd probably use that EFI safe throttle body cleaner menat for cars that have a varnish coating on their inside that is meant to prevent carbon build up. I bet that stuff won't eat the varnish on the windings. But, after that, I'd still want to spray it with something like WD40 (or something better) that will protect the electronics from any future rusting. Otherwise the coil might die a slow death.
Important to do with a control box as well if it's ever dipped in water, especially salt water. If you don't dry it completely and then spray the board/switches, etc with some form of electrical cleaner that has anti-oxide compounds in it you are asking for a slow and painful death of the machine.
Many people think if electronics that are currently running get dunked in water they are done for. While that can happen, usually if you remove the battery right away and let it dry out well it'll work just fine again. Just have to make sure to spray the electronics with something that is non-conductive, yet will prevent any potential rust in the future.
Far as BBS coils, there are a few that are not epoxy filled and risk water damage. The 5" Excelerator obviously, the Coinsearch coils, the old Sun Ray solid S-12 I think, not sure about the S-5?, and now the new 13" Ultimate. Some are using the Ultimate in the water, but for sure I'd seal the coil nut underneath on it's threads and the hole below it with something like Shoe Goo. You want something thick that when dry won't be rigid and develop cracks with stress. Shoe Goo is perfect for this. I also gum up the coil cable right where the rubber sleeve slids down with the coil cable nut, so that that sleeve is sealed to the coil cable. I do this with all my coils, epoxy filled or not, as I fear water might wick down even an epoxy filled coin to the windings or pre-amp.
If a coil tries to float its a sure sign it isn't filled with epoxy. I've seen epoxy filled coils such as the BBS 8" coils with wide splits in the seams on the coil casing due to wear in the sand water hunting, and yet the coil still functions as the epoxy makes there no easy way for water to get to the windings or pre-amp. Still, no reason to chance it, so I covered that coil with generous heavy coats of spray on bed liner to both fill those cracks and protect it from future wear.
While some are using the new ultimate coil in the water I personaly wouldn't risk it myself.
Most spiderweb coils (and all of them for the BBS machines far as I know, except the Ultimate) are filled with epoxy. Many solid coils, in particular older ones, weren't filled with epoxy to save weight. Modern coils that seem lighter than usual, such as the Tornados or the S-12 MAYBE (?), are probably using micro balloon technology mixed with the epoxy to drop the weight of the epoxy. This stuff is mixed with the epoxy trapping air in it, so that you still get solid and rigid waterproof protection, but the weight is now a lot less. I'm just guessing that that's used in modern coils, because this stuff is using in RC plane construction these days when glassing wings and such to make them rigid yet not heavy.
By the way, I think Raulph from Sun Ray chimed in in the Sovereign forum's coil sticky and told us whether the S-5 is epoxy filled or not. Can't remember off hand. If anybody is considering the S-5 in the water be sure to skim over that sticky and see if he says anything about it. I'm pretty sure he said the old white solid S-12 coils were not epoxy filled, but of course we know the modern spiderweb frame S-12 is rated waterproof as it's very popular among water hunters for both coverage and low drag being a round sleek coil. The SEF coils are also waterproof and I know they are epoxy filled, but never the less the BBS versions of those coils are pretty darn light. Lighter than the 10" Tornado in fact if you ditch the coil cover and use spray on bed liner on the bottom to prevent wear.
One more thing, although the old 8 and 11" coinsearch coils by Minelab were not rated waterproof, I have read of people using them in the water.
Oh, and in relation to the stuff about epoxy filled coils seeming to be lighter these days, all you have to do is compare the weight of the old 8 and 10" BBS coils to the modern Tornados of the same size. MUCH ligther, yet epoxy filled just like the old BBS versions, which were boat anchors!
