Viking Marine has closed and shut its doors after decades of supplying deck plates and hatches. The products below are discontinued, but left here for reference. Scroll Down for Necky (bottom), Screw-in Hatches and Rectangle Hatches.
The Viking 6 Inch Twist Lock Hatch (PLT-6), shown at top, was common on some Necky and Hobie brand kayaks (such as the Necky Gannet and the Hobie Pursuit). It may be found on a wide range of other kayak brands too. The Rim outside diameter was 9 inches. The lid measures 6 and 1/2 inches in diameter. Deck Cut-Out was 7 ¼”. Use the Sea-Lect 8 inch Performance Hatch and Ring for a substitution. You will have to remove the old rim and re-install. The 6 Inch Bag Adaptor Ring might be handy to have on hand as a backing plate, it will also support a bag. Gain insight on how to: Installing A Six-inch Hatch.
The Viking 8 inch Twist Lock Hatch (PTL-8) was common on some Islander, Perception, Hobie and Heritage, some older Seda kayaks, and the Aquaterra Big Kahuna. This was often used to retrofit the Hobie Hinge Hatch. Rim outside diameter was 11 and 3/16 inches. The lid measured 8 1/2 inches in diameter. Deck Cut-out was 9 ¼”. These Viking 8 inch hatches came with two handles or one. This is the same hatch in the discontinued Harmony kit 9810033. To replace one of these use the Sea-Lect 10 inch Performance Hatch and Ring as a substitute. You will remove the old rim and re-install. A Backing Plate might be handy to have on hand. Gain insight 
on how to: Installing A Six-inch Hatch.
The 10 inch Twist Lock Hatch was commonly found on many Heritage, Perception and Islander brand boats. (It was also used as a retrofit for Walden Kayaks 10 inch hatch.) The lid measures 10 and 1/2 inches in diameter. Rim outside diameter is 13 and 1/8 inches. Deck Cut-out was 11 ¼”. These Viking 10 inch hatches came with two handles or one. For a substitution please use the Riot 10 Inch Hatch.
The Viking 4 inch Screw-In Hatch (1168 with bag option) was best for small spaces 5.75 inches in diameter. Cover and deck cut-out are 4 and 5/16 inches in diameter. Commonly found on some Necky brand Dolphin and Spike sit-on-top kayaks outfitted with rudders. Also found on some Ocean Kayak Knee Tree thigh braces, for the Yahoo white water kayak. Many of the 4 inch Deck Plates can be used as a substitution. Try to match the foot print (rim OD) as closely as possible. You will have to remove the old rim and re-install. See how: Installing A Six-inch Hatch.
5 inch Viking Screw-in Hatch: Viking Marine Part Numbers 1057 and 1099. Some rims supported a removable 5 Inch Hatch Bag. The rim is threaded, see photo to right, the cover screws on with several turns. Rim outside diameter is 6 and 3/4 inches. Lid is 5 7/16 inches in diameter.
The Viking 5 Inch Hatch was commonly found on many Aquaterra, Islander Perception kayaks and some older Wilderness Systems kayaks (pn 8025319). Most five inch screw hatches all 
have the same cut-out template and six bolt pattern. While the lids from one brand of hatch will not fit the rim of another brand hatch, the large hole and six small screw holes on your kayak deck will accept most five inch screw-in hatch brands.
The 5 inch Viking Screw-in Hatch can be replaced with: The any of the the 5 inch Deck Plates (use the link to the left) or the 5 Inch Hatch Kit (use the link to the left). Please read the product descriptions carefully for bag information. Some tips: Quarter Turn deck plates are easy to open but not as secure. Screw In deck plates are more secure. Not all rims support a bag, read carefully. A new rim will have a new O-Ring seal, and will provide dryer storage. A reinstall of the hatch rim will make your kayak better than it was. Gain insight on how to: Installing A Six-inch Hatch.
See the related article about the Five Inch Viking and Beckson deck plates: Lost a Kayak Hatch Cover? What now? PART II
6 inch Viking Screw-in Hatch was commonly found on many Ocean Kayak, some Necky (mostly sit-on-tops of the 1990s) and other popular brands such as Aquaterra and Perception. Some Viking rims can support a Cat Bag or Fat Bag. This is the same Viking brand hatch as the Ocean Kayak Six Inch Hatch Kit that had 18 screws holes. Viking Part Numbers 1158 and 1140. Ocean Kayak part number 07.2138.0000 and 07.3014.0000. The rim outside diameter is 8 and 1/8th inches. Lid is 6 3/8 inches in diameter, and matches the deck cut-out as well as the rim opening. Screw holes are 7 3/8 in. on center, opposite screws. Many of the 6 Inch Deck Plates can be used as a replacement. Try to match the foot print (rim OD) as closely as possible. Gain insight on how to: Installing A Six-inch Hatch.
Fat and Cat Bags are not water proof. Some round Viking deck plate rims will not support a cat or fat 
bag. This makes the opening slightly larger. A visible ledge around the hatch opening will indicate if the rim can support a bag. This makes the opening slightly smaller. Fat bags are short and very wide, see bag on left. Cat Bags are long and skinny, usually with a draw string and a Viking tag, see bag on right. Visit the Hatch Parts Category for remaining Viking cat or fat bag stock as well as other compatible Hatch Bags.
The Viking Utility Hatch (1190) was used as a hatch for the Ocean Kayak Prowler Big Game, center position, and could be added to any kayak with a flat deck space that will accommodate the 16.5 x 13.25 outside dimensions of the hatch flange. Hatch Cover is 13 1/4 x 9 1/16 inches, the usable opening is 8.5 x 12.75 inches. Ocean Kayak Prowler Big Game Hatch Kit (07.1897.0000) Link to original OK instructions. Take note! The foam rubber gasket will leak over time! For the best results remove hatch rim and reseal with Sealant. This link will provide insight into how this job is done: Installing the Cobra A Hatch. The original hatch opening may need to be closed or made smaller in order to replace the original hatch with a smaller round Deck Plate. Get the Hatch Patch Pannel to do that. Click the links above and the patch link, for more info.
All Viking Hatch Covers were often white or ivory in the powerboat or sailing sectors. Viking hatches for kayaks are almost always black. Color has no bearing on fit. Viking hatches were made of ABS or polypropylene. Both Viking plastic types are very common on many kayaks.
Viking O-Ring Info: There were two types of O-Rings common on these Viking hatches; Screw-In and Twist-Lock. The Screw-In O-Rings were thin black rubber standard rings. These were simply press fit into a groove in the rim. While these may be sourced from industrial hardware suppliers they will be very difficult to re-seat. The Twist-Lock O-Rings were more like gaskets, flattish and glued onto the rim. These might be restored with standard weather stripping or self-adhesive foam products. We do not have any more information on O-Ring selection and replacement other than what is published here. Both types can be compromised over time and potentially leak. Screw-In rings will sometimes become dislodged from the groove or be pitted badly from sand. The Twist-Lock gaskets can also become pitted with sand and the glue can fail. Both can be compressed to a point where they no longer seal. If you have a failed O-Ring Gasket is it best to replace the entire hatch.
Attention those looking for Necky Hatch replacement options! The info on this page will help guide you to find replacements for Necky hatch covers. The Necky company used several versions of Viking brand hatch covers for their kayaks depending on model and year.
Viking 4 Inch Screw Hatch: Necky Kyook bow as well as Dolphin and Spike sternmost access port for rudder mount.
Viking 6 Inch Screw Hatch: Necky Alsek and Kyook bow, Dolphin, Dorado and Spike center.
Viking 6 Inch Twist Lock Hatch (aka T-Toggle): Necky Gannet solo, Gannet tandem and Tike stern.
See more information at: Kayak Hatch Replacement Options Part II - Deck Plates.
