Micro-LPVs
Some Low Profile Vessels were very small and fitted somewhere between Human Torpedoes and Explosive boats. Note the vents and T-shaped outlet over the forward hull, key indicators for LTTE LPVs.
5. Semi-subs
Taking the low profile considerations a step further, semi-submersibles run almost completely submerged. However, the cockpit, air intakes and engine exhaust are usually above the surface. They have to be built more strongly than LPVs, with the most elaborate versions running completely submerged except for the snort masts – these are called
’snorkel subs’.
First large steel semi-sub
This craft was found in shallow water along the Vellamullaivaikkal coast in June 2009. Although described as a submersible, the twin snort mast (air in, exhaust out) and single propeller suggest that it is a semi-sub. Additionally the access hatch is square which is not ideal for true submersibles. It does have large ballast tanks running along the sides however so would have had the ability to control its operating depth. The mild steel craft was 7.3m (24ft) long (without rudder or warhead on nose) and 1.2m (4ft) across.
from www.defence.lk/
Steel semi-sub #2 Gokulan-24
Another steel semi-sub, this time captured in 2008. The forward and aft hydroplanes are visible, as is the small rudder. It was 5.4m (18ft) long and 1.5m (5ft) across. The writing is a male name, Gokulan (கோகுலன்), although the meaning is unclear.
from eelavarkural.wordpress.com/2009/09/28/