Discovered by divers in 1990 and sitting at a maximum 28 metres on a sandy and shingle bottom, it seems very little is known about ‘The’Pin Wreck’, debates including her propulsion method and usage. There does not seem to be any photography or videography on the Internet, other than our own recent roll and reel herein. One thing is for sure, the name ‘Pin Wreck’ stems from the fact that the timber was fixed to the double skinned hull (possibly copper) with bronze pins, some 12″ long. It is a small vessel for sure, hull and timber still in situ with two anchors and large capstan with winches and gears. It is thought she sank around 1880 to 1890.
One theory is that she is a Nightingale class ‘Revenue Cutter’, a military vessel called the ‘Sprightly’ that sunk in 1891. There is a dive report on the Yorkshire Divers Forum in April 2009 that replicates our own sightings. The dive report spawns this theory, being the only wooden ship sunk in the area and era. In the report, contributor @stevechesh references a UK Hydrographic Office report in respect of the Sprightly in that a “button from marine light infantry” has been found.
Interestingly, I also read this Old Harbour Divers’ document dated 2010 that also references the Pin Wreck, stating that “brass military tunic buttons have been found”. I wonder if the Old Harbour Divers document dated 2010 has published the comment having read the Yorkshire Divers Forum post?
In a DiverNet article, the site is referenced as a wooden-hulled trawler most likely used as a diving platform, as bits of standard diving dress have been found on it.
But is this a red herring? The UK Hydrographic Office references both a divers boot being found on the same report as the military tunic button. I guess the questions are,  where is the boot and where is the pin and  when were they found? 
An Admiralty Ship
It is noted that there are /|\ Admiralty marks on the bronze pins, suggesting the vessel was built for military use. That however, does not mandate it was in use as a military vessel at time of sinking.
The unmistakable striking feature is what is perceived to be a anchor capstan and gears that protrude some three metres midships on a vessel that is some 30 metres in length and 5 metres wide. There are two Admiralty Pattern (AP) anchors (adopted by the British Admiralty in 1852) to what is believed to be the bow. Then there are the 12″ pins and visible timber, though not as many as one would think, presumably recovered by divers on previous explorations. She sits in roughly a north to south position, across the side with bow facing north.
This is either a barge or a sailing vessel. There is a boiler midships but this looks to be part of the strange machinery close by. Mainly this comprises three large wheels on shafts. Perhaps some sort of salvage machinery. Divers call this “The Pin Wreck” due to the copper or bronze pins holding the hull together. These have an Admiralty mark. The lower hull is also copper sheathed. There are two tanks in the after section of the hull. Two wooden posts stand up then the stern post. The depth here is 27m and the top of the “machinery” is at 24m. Two anchors lie at the bow. One is part buried. A single post stands here.
But Is This HMS Sprightly?
An interesting question as Wrecksite.EU does not list a HMS Sprightly in its archive of wrecks, though WikiPedia states that HMS Sprightly sank off the Isle of Portland in 1818. The WikiPedia page referencing HMS Sprightly as a Nightingale Class states she would be carrying two 6 pound cannons and four 6 pound carronades . For sure, neither we, the Yorkshire Divers Forum article or Nick Chipchase references any canons or carronades being found. WikiPedia also references other Nightingale Class Cutters of the same era, HMS Racer , HMS Speedy  and HMS Snipe .
I can find no reference to the ‘Nightingale Class’ type Revenue Cutters of the early 1800s other than the four named ships on WikiPedia. It could be a plausible theory that The Pin Wreck could be HMS Sprightly, but where are the canons and carronades? There are a number of model maker websites that support this theory, though the winches, gears, boiler and capstan do not appear in these model photographs.
One thing is for sure and that is, the wreck is still a mystery. The Yorkshire Divers Forum conclusion that this is not a steam propulsion vessel, is probably are valid. As they state, no engine or propshaft have been identified and that the boiler is more than likely a ‘donkey boiler’ for the steam anchor winches. Nick Chipchase assumes a barge or saying vessel and the there is a boiler midships. But what was the boiler used for? We did not see any boiler, but then again maybe we were not looking for one. I find it strange that the UK Hydrographic Office references both a divers boot and a military tunic button being found at the site and maybe the divers boot is a red herring.
I think for sure that with the above information, it would make sense to revisit this wreck and research a little more.
Two videos from Mike and I: