A diary entry from Stoddard Lane, a World War I ambulance driver. His brother, Homer Lane, was the CO of SC 86. It’s the summer of 1918. Thanks to Jim Hamilton for submitting it to The Subchaser Archives. 
I've changed some fine details such as changing "+" to "and" for readability, and excerpted the parts about hunts from a longer passage.
After effort I located a hotel (Duke of Cornwall) and had a sleep in spite of raging storm. Was Homer there or was he not? I’d made up my mind that he’d surely must; I was deadly afraid of being disappointed. But he was there – at the Base – a surprised boy to see me. Somehow we got thru a lecture on the “K” Tube and then went over to USSC 86 lying over behind its mother ship. I inspected the craft and found her good – compact, well equipped fairly comfortable. And how.
... Next day we were in “Stand By” and had an emergency call. Made a quick get-away about 7 P.M. and headed to the S.E. for Start Pt. S.L. [he means himself] at helm, three chasers in the group. Some sea – not much. Fun steering  and rather strenuous work after it got dark and it had to be done by compass. We lay miles off the coast all night with the tree tubes working, shifting position once in a long while. Spent two perfect nights and one perfect day - then went back to Plymouth to be shipped right out again to work off Eddystone, where a sub had been reported as sighted. A dirigible worked with us, semaphoring often to know the dope – a big silvery tadpole effect. Planes constantly searching too. Baker’s boat (85) was operating with us, and part of the time a British converted yacht. The yacht thought it got something so did the other chaser. 
We got the angle on it – instructions from the yacht – then headed out to sea, - full speed – call to quarters – guns manned signal to drop cans. Stern can goes – then the two from the Y-gun – the old boat is boosted out of the water and shaken considerable – big hills of water shoot up (bombs dropped at 100 ft. containing 300 lbs of TNT) Lots of Pep! Other boats drop bombs simultaneously, then the stern wire device is lowered, but no bell rings. Did we get the victim? We don’t know. Pr’aps. No signs of oil, tho. But plenty of dead fish for next day’s lunch – good, too.
This seems to describe events from 10 July 1918 and 11 July 1918, although some of the details don't line up with the attack reports. SC 86 is not listed as taking part in the hunt on 11 July. Possibly he was on a different chaser that day.
The notes on the trailing wire ("stern wire device") are particularly interesting, in that they were using the device in July. The chasers at Corfu abandoned the device altogether, and there are very few reports of chasers anywhere actually using it.