Fitting Hatches, Portlights and Vents in Hatches . . .

Fitting a new or replacement hatch or portlight can be a simple and rewarding procedure. By following these clear instructions you will be able to complete the job easily. But remember the most important part of fitting a new hatch or portlight is, forward planing.

Before you order your hatch or portlight, you need to make some straightforward measurements. When replacing an old
hatch or portlight, carefully measure the old hatch and aperture, you then have the information to hand to make your choice for the selection.

When you are replacing an older hatch or portlight and you would like to find a direct replacement, the standard cut out sizes have remained constant, however the corner radius may have changed on certain makes and models. If you cannot match up a new hatch or portlight with the existing range of cut outs, the only solution may be to build an intermediate frame from timber.

if you are selecting a location for a new hatch or portlight you must make sure the surface is flat with a maximum tolerance of +/- lmm. You should also consider that if you are fitting a new hatch or portlight, cutting a hole in your boat might compromise the structural integrity of the boat. Hatches and portlights should not be considered as stiffening members and it is recommended that the deck be adequately stiffened to prevent distortion during heavy weather. If you have any doubts about the location you are going to place the hatch or portlight, you should consult a yacht designer or surveyor.

This guide will help you choose a particular hatch or portlight, however you will have to take time and read the hatch and portlight location guidelines in this booklet, as the CE regulations stipulate where certain products may be fitted.

With this simple well illustrated guide, choosing your hatch or portlight is easy, don't forget that the most important part of the task is not fitting the hatch, but planing the job well and having the correct tools to hand.

The following checklist takes into account all the issues normally encountered when planning a hatch or portlight installation.

General
Hatches and portlights should be fitted to a flat surface with a maximum tolerance of +/-Imm.
For decks of composite construction (e.g. GRP) it is recommended that the exposed laminate be sealed with the appropriate material prior to fitting the hatch.
Openings in metal decks should have all burs and sharp edges removed. It is recommended that the lower frame of the hatch is suitably insulated from the deck if there is a possibility of electrolytic corrosion with the aluminium frame of the hatch.
Hatches and portlights should not be considered as stiffening members and it is recommended that the deck be adequately stiffened to prevent distortion during heavy weather.
Cutting holes in deck and hull can compromise the structural integrity of a boat. If in doubt consult a competent yacht designer or surveyor.

Portlights
Portlights have a maximum and minimum deck thickness to which they may be fitted. Portlights fitted to hulls approaching the maximum deck thickness may have restricted opening. Portlights require different fastenings to suit different deck thickness. If the fastenings supplied with the portlight do not suit your hull thickness it will be necessary to order the required fastenings separately.

Hatches
Hatches should not be opened and closed more than necessary until the lower frame has been securely mounted to the deck. Hatches may be fitted to decks of any thickness. However, on thinner decks the flange in the lower frame may intrude into the cabin. If a Trimkit is being fitted the size of the hole cut out in the boat must be increased by 3mm. Hatches lids have to be opened past 90 degrees in order to fastcn the hatch to the deck. If an obstruction stops a hatch opening this far it will not be possible to fit it. When a hatch is fully open the lid should come to rest so that it is supported near the edge with the handles. If this is not the case, and the lid is supported near the hinges, the leverage on the lid may cause the hatch to be damaged.

Tools/Consumables
> Bedding compound and application gun (silicone)
> Fastenings (supplied with portlights)
> Power drill and set of drill bits
> Jig -saw
> Screwdrivers, Allen keys, spanners depending on product
> Compass (for marking hatch radii)
> Felt tip pen
> Ruler

	Retro Hatch Fitting Mark the cut out dimensions of the hatch onto the deck, remember if a trim is being fitted it will be necessary to increase the cut out by the amount stated.
	Offer the hatch up to the marked out dimensions to check accuracy.
	Cut and Drill Take care to avoid any power cables, gas pipes or other services. Please ensure you use the appropriate safety equipment such as electrical power breakers and safety glasses. Drill a hole for the jigsaw on the waste side of the cut line.
	Use a jigsaw to cut the aperture through the boat. It may be necessary to cut or remove the headlining.
	Alternatively - A hole cutter that matches the corner radii may be used to cut the corners.
	Test fit the hatch before applying sealant.
	While the hatch is in place, mark the lower frame fixing holes.
	With the hatch removed, drill all fastening holes.
	Bed Down & Seal When you are entirely happy with the installation of the hatch, apply a generous bead of bedding compound all the way around the frame where it comes in contact with the deck. Apply sealant to both sides of fasten holes on the hatch frame. If replacing an existing hatch fill any old fixing holes with sealant.
	Refit the hatch to the deck. Around the hatch frame a small amount of bedding compound should be forced out of the gap between the frame and deck. Fasten the lower frame to the deck.
	The hatch should be through bolted in the hinge areas while self tapping screws can be used for fitting the remainder of the lower frame to the deck sheet.
	Clean up the excess bedding compound.
	Finished hatch installation
	Mark the Cut Out Cut out the template that is provided with your hatch. Check that it is accurate by placing it over the back of the portlight. Portlights should be fitted to a flat surface (+/- 1mm) Tape the template to the boat and mark the cut line.
	Cut and Drill Take care to avoid any power cables, gas pipes or other services. Please ensure that you use the appropriate safety equipment such as electrical power breakers and safety glasses. Drill a hole for the Jig saw blade on the waste side of the cut line.
	Use the Jigsaw to cut the apperture through the boat.
	It may be necessary to cut or remove the headlining.
	Test Fit Port lights are fitted by clamping the outer frame against the deck using the inner frame fitted inside the boat.
	Test fit the portlight and clamp ring before applying sealant.
	When you are entirely happy with the installation of the portlight, remove and set it aside. Apply a generous bead of bedding compound all the way around the frame where it is in contact with the deck
	Refit the portlight to the boat. A small amount of bedding compound should be forced out of the gap between the frame and the deck the whole way round the frame.
	Clamp the inner frame to the outer frame . Ensure the fixing threads are greased.
	Clean up the excess bedding compound.
	Finished Portlight installation.
	Drilling and Cutting When cutting or drilling acrylic it is necessary to come in from both sides. Drilling or cutting all the way through will result in the acrylic breaking out when cutter comes through.
	Tape the vent template to the hatch ensuring it is clear of all handles, stays etc.
	Drill a pilot hole for the hole saw.
	Cut the hole through from both sides.
	Using the appropriate size hole saw.
	Drill pilot holes for the fastenings.
	Drill the fastening holes also from both sides
	Assemble the ventilator with inside, o-rings and seal all in place.
	Fit to the hatch.
	Fasten from the inside.
	"Pull down plunger to close"
	This type of vent may also be fitted to decks. For top down fastening use sealant to seal the screw holes.
	The product and text used for this report pertain to Lewmar Products.