Lewmar FLUSH 2G Guide

1
Fitting Instructions
Flush hatches should be tted to a at 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 tted into a recess in the deck. The recess must be to the shape specied
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 tting 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 tting 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. Modication of the hatch by the tting of vents etc. will invalidate the compliance with
the standard.
B5978 Issue 6

Flush Hatch Fitting & Adjustment Instructions ref B5978 iss.6 | 2
The locking ventilation position is used by closing the handles into the catch block center slot.
Care should be taken not to stand on or load the hatch lid in this position, as damage could occur
to the handle or catch block.
Always wash the hatch with soap, water and a soft cloth. Never use abrasive or solvent cleaners on the
acrylic lid, as this may at a later date damage the acrylic.
3G hatches are intended predominantly for light and ventilation. Sizes 44, 54 and above are also
suitable for emergency access/evacuation, in accordance with ISO 9094, provided they are tted
with exterior handles. Protect the seal if used as regular access for people, sails or equipment.
To avoid risk of injury care should be taken to keep hands and limbs clear of lever and lid pinch zones while
operating and adjusting the hatch.
User Notes
Position lower frame over hole and drill two xing screw holes in opposite corners. Insert
appropriate stainless steel fasteners (see below).
* Be careful not to damage paint when drilling
* For ideal xing use Silicone or Tef Gel under the screw head
* Be careful when xing screws - Do not DAMAGE paint
Deck type
Wood M5 through bolts or marine grade wood screws.
(Torque to 2.25 - 3.0 Nm)
Standard ply / Marine ply - 3Nm
Hardwood - 2.75Nm
Softwood - 2.25Nm
GRP/Steel/Al Alloy M5 through bolts or machine screws into suitable tapped plates.
(Torque to 3.0 Nm)
Fixing Sizes M5, 10UNC, 2BA, 3/16”, Wood screws (min. length 40mm).
Hinge Fixings M6 or 1/4” through bolts only.
Drill remainder of holes and fasten down from the center working out to the edges. Clean off surplus
sealant.
Through bolts should be used where xings pass through lower hinges (M6 or 1/4” only).
Once installed check again for correct operation of the hatch lid, i.e. closing/locking, even pressure
of seal etc.
In the case of 3G hatches, suitable protection should be given to the lower frame seal for the
duration of the boat construction. Failure to do so may result in damage occurring to the seal
from hoses, cables etc. being dragged over the seal surface.