Then you would lose your money. What on Earth would those puny little shells do to the armour on a destroyer not to mention their range was nowhere near the guns on a destroyer, and at distances over a few kms they would be relatively inoffensive. They were designed to take out wooden ships and even later when most fleets sported iron ships of some sort their power was not comparable at all to modern weaponry.
Puny little shells? The Royal Sovereign (the quintessential pre-dreadnought) fired 13.5 inch,
570 kg shells up to a range of 12000 yards. Would they hit anything at that range? Pre-dreadnoughts at Tsushima scored hits at 7000 yards (though admittedly the Japanese were probably the best at naval gunnery at the time, at least until Jackie Fisher had his way with the RN).
A WWII destroyer (Fletcher class - one of the largest, most advanced and most successful WWII destroyer classes) fired 5 inch
25kg shells that are physically incapable of penetrating pre-dreadnought armour even at its thinnest points at anything more than 4000 yards, and utterly incapable of penetrating its armour anywhere else even at point-blank range.
The Royal Sovereign had
18 inch belt armour, its thinnest being five inch at the upper belt, and 17 inch gun armour.
A WWII Fletcher class destroyer had an 0.75 inch plate hull, with
no armour. A 13.5 inch, 570kg shell is going to go right through that like a hot knife through butter, as are its 45 kg secondary shells. Hell, even its six-pounders might have a chance.
To respond to your edits:
For one thing the effective range of a destroyers guns was up to 15km, and even at 5km the pre-dreadnaught would be so far out of range as to be stupid.
See above, pre-dreadnoughts scored hits at 7000 yards, effective range could be up to 12000. A destroyer is not doing anything at all to it beyond 4000 yards.
A pre dreadnaught ship would be raped by a post dreadnaught ship in the early 20th century let alone an A type destroyer in WWII, with the advent of the dreadnaught class all pre dreadnaught ships were made obsolete overnight.
Yes but a destroyer is not a capital ship, nor intended to be able to fight a capital ship. It's a picket, sub and torpedo boat destroyer, with AA capacity.
A destroyer would typically be fitted with some sort of below the water attack method from about 1905 onwards. 1 hit from those would sink an Ironclad, being as they are lumbering whales for the most part in comparison to the destroyer I would expect the destroyer could sink them with torpedoes easily too.
And well before - the torpedo boat destroyer was designed in response to torpedo boats and were generally torpedo boats as well. Ship-launched torpedoes are not the most effective weapons simply because the necessary range is much greater, leaving buckley's chance of scoring a hit against anything unless you have a simultaneous wide spread from multiple DDs at once against a packed fleet with limited room to move. And you remove the element of surprise, giving anything plenty of chance to move out of its way, especially a pre-dreadnought steaming at 17 knots (they weren't so slow as people imagine - far faster than WWII freighters). And if you get closer, you get a 13.5 inch shell in your face, even if you get past the capital ship's pickets.
EDIT: I agree that the destroyer's only chance of sinking a pre-dreadnought is via torpedo, but that chance is extremely small in comparison with the destroyer's chance of being demolished by shelling.