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Fitting Instructions
Flush hatches should be fitted to a flat surface with a maximum tolerance of +/- 1mm and a
minimum deck / hull thickness of 15. Check that all fastenings will be clear of deck moulding radii etc.
Do not open and close the hatch more than necessary until the lower frame is securely mounted.
The Flush Hatch must be fitted into a recess in the deck. The recess must be to the shape specified
on Lewmar’s drawings. The recess is normally included in the deck as part of the design process for the boat.
The hatch should be mounted with minimum of 10mm between the hinge edge of the acrylic and the edge of the
recess and a maximum 8mm radii at the base of the recess. See drawing below.
It is essential that the lower frame is placed square on the deck opening. The operation of the hatch should be
checked before sealing and fastening to the deck. Each installation should allow for either drainage channels or tube
around the hatch to ensure no excess water can become trapped.
When fitting a number of hatches it is advisable to prepare a template.
Where the deck is of composite construction, it is recommended that the exposed laminate be sealed
with the appropriate material prior to fitting the hatch. Openings cut in metal decks should have all burrs and
sharp edges removed.
Hatches should not be considered as stiffening members and it is recommended that the deck be adequately
stiffened to prevent distortion during heavy weather.
Re-check the frame on aperture and then apply bedding compound to the channel in lower frame.
Bedding compound must have good adhesive qualities (e.g. silicone sealant), be a suitable grade for marine
sealing applications, of 3mm minimum thickness and compressible to allow the lower frame to be pulled down
in contact with the deck by the securing screws.
Flush Hatch Fitting & Adjustment Instructions
(To be retained in owner’s manual for future reference)
Flush hatches are for use on all craft types in accordance with
ISO/DIS 12216.2002, DESIGN CAT “A”,
AREAS IIa, III and IV.
Modification of the hatch by the fitting of vents etc. will invalidate the compliance with
the standard.
B5978
Issue 6
