--Originally posted 6/1/09--

Going into WWII there was a second, minor casing bulge, forward of the deck gun platform, which appeared on just a few S-18 boats - but those included the S-37 boat which I am building:


Click on Image to Enlarge At left is the sole implicating pic of S-37; undated, but the all-black camo indicating an early- or immediately pre-WWII time frame. Likewise, at right, during WWII the same conical flaring of the forward casing, approximately abaft the crew access hatch, is seen; at top, on S-41 in 1942, and on S-28 in all the other pics, taken in June, 1943.

At first, I took this casing bulge to be enclosing an enlarged forward escape trunk, or similar, uniformly surrounding the forward hatch. However, close inspection of the above, overhead pic of S-28 (right, at bottom-right), revealed it to be located starboard-side only; accommodating a second hatchway or trunk, covered by a circular plate, located just aft and outboard of the crew access hatch, and of roughly the same diameter.

I also realized that, In pics from any other angle(s) than above, this second hatch/trunk would appear all but undetectable. So I re-examined all available S-18 pics, for traces of this feature:


Click on Image to Enlarge At left, pics of S-28 - all from dates we know she carried this forward trunk - show how subtle are the indications of it, when viewed from less advantageous angles. Viewed head-on (upper left; top inset), the trunk hatch or cover plate appears - behind the clutter of stanchions - just to the left of the dark, raised disk of the forward hatch; it appears as a light, similarly-sized disc, not raised but instead slightly countersunk into the deck. At bottom (and middle inset), viewed across the deck from portside, appearing in about the right place is what looks like a slightly raised cover (with sailor apparently handling it), having a bellows-looking skirt or shroud apparently suspended underneath.

At right, earlier pics allow us to begin to set boundaries on the dates when these trunks were installed. At top, a pic of S-28 misdated "mid-late '30s" must, due to the all-black camo and other features, date instead from the early '40s; either just prior- or early in WWII. Although a heavy stanchion (from the foreground sub) directly screens the view, an open, forward trunk shaft - with no cover apparent - can be perceived, as well as the casing bulge to accommodate it. Note again, the rim appears slightly recessed into the deck, and mooring (or electrical) cables appear to be going down it. At bottom (and middle inset), S-28 is moored inboard (foreground) on May 4, 1923, clearly showing no evidence of the trunk; neither any countersunk feature(s), nor any bulge(s) in the (far side of the) casing. Do note, however that S-28, and S-25 next to her, both exhibit angular hatches/doors opening out of the deck just aft of this area; a large one opening forward, and smaller one, just ahead of the gun platform, opening outboard to starboard.

Clearly, the forward trunks in question did not appear until after - by all indications long after - the boats entered service:


Click on Image to Enlarge At left, the boats were launched - like S-37 on June 20, 1919, at top-left - absent, of course, the forward trunk or in fact any casing bulge(s) at all. Instead, what appeared in its place was a recessed cleat, as seen at top-right (upper insets) on other boats (S-38 & -40) as late as the "early '30s". The overhead view of S-37 at center (middle-left inset) reveals no evidence of the trunk - neither a round cover, nor casing bulge (behind the sailor coming out the forward hatch) on its date of 10/29/24. More to the point, the bottom pic, again dated "early '30s", clearly confirms no forward trunk but instead the recessed cleat, described above.

Likewise, at right, two pics taken (undoubtedly minutes apart) the same day in the early 1930s, reveal S-41, moored outboard S-38 and -40 to show no trace(s) of the trunk in question, but instead faint indications of the starboard-side cleat, and mooring lines tied to it; behind S-38's deck gun sights (bottom-right inset).

Thus, none of these three boats - S-28, -37 nor -41 - appears to have gotten this forward trunk before (at least) after the early 1930s; very likely, not even until the early '40s.

Finally, evoking "variations on the variations" within this class, there is subtle but repeated evidence of a yet smaller, forward "mini-trunk" on (at least) two boats:


Click on Image to Enlarge At left, S-31 from overhead, dated "1943-1945" is in the mid-WWII refit and shows what looks (despite the graininess) like a half-moon cover - cut straight along the outboard edge; flattening the casing bulge accordingly - in precisely the forward trunk location. At bottom, in March of 1929 it was absent from S-31; the earlier starboard-side cleat appearing (in an equally grainy view) in its place. At center, similar observations hold for her immediate-next-of-kin sister, S-32, appearing, at top, on January 31, 1944 with a small but distinct slanting ripple in the casing; consistent with a flattened bulge (i.e., bisected cone) at precisely the right spot. At bottom-left, a closeup dated 1942 is again (maddenigly) obfuscated by a sailor's hooded head, but clearly shows deck planking interrupted by a rounded patch of smooth plating - possibly also with minor outboard bulging of the casing - and a notable lack of mooring lines going to this spot, as well. At bottom-right, still earlier, in April, 1941, mooring lines do tie into a starboard cleat at this spot, however just aft there is indication of the (light) casing bulging slightly, as well as a (dark) possibly open cover; directly behind the keister of the squatting sailor.

At right, yet earlier pics of S-32 - the top two before (at least) March, 1932, and center again from March, 1929 - all confirm the lack of any forward trunk and/or presence of the (black-painted) recessed cleat, in its stead. However the top two do exhibit bright patches possibly consistent with the early, further-aft door, shown open on S-32 in the bottom-right pic; undated but identifiably early (per the style of limber holes). Located just ahead of the gun platform - i.e., just aft of the future forward trunk site - I strongly suspect that something(s) of its contents, exposed earlier to free-flooding in the casing, were moved forward and down into the protection of the pressure hull by the forward trunk- and "mini-trunk" refits, installed just before WWII, but in any case not widely adopted by other boats of the class.


Cheers,

-Matty