Glue Fixing

We at SeaMac strongly advise that windows are glue fixed, maintaining a minimum of 2 to 3mm of adhesive behind the flanges. This is to allow for expansion and contraction of the window and also to assist with removal in the event that it needs to come out again. The window frame and boat should be ‘masked off’ before attempting to install, positioning the tape so that once coved off, only a clean radius of sealant is visible. This should be done externally during installation and internally as required to ‘finish off” at a later time. Pre fitting will insure a good fit and lines can be drawn to aid in the positioning of this masking process. 


Windows can be fitted straight into a cut opening, can be rebated into the cabin side, and the wall thickness can vary from 4mm or 5mm to 100mm or whatever. SeaMac windows are fitted from the outside and the internal finishing work is done to suit penetration of the window through the aperture (please see the attached sheet). A simple radius on the inner exposed corner of the boat prior to fitting will provide a nice clean paint finish, or if required a nice rounded approach if front runner or some other applied inner surface is to be used. 

Window cut outs should be done carefully ending up with straight lines and neat radii, so as to minimise difficulty when finishing off around the windows. It is important to note that the windows should not be used as support for anything overhead or adjacent. They need to have 1 or 2mm min of clearance to all sides so that no stress or pressure is applied to the frame from the vessel. In particular, if building with steel, it is imperative that no contact between the window frame and steel is made, otherwise electrolysis will result and the window will need to be replaced within a very short period. 

Curves and Bends

With regard to a curve in the hull/cabin side, a fixed window will accommodate a small amount of curve.

Depending on the window shape, size and glass thickness, this is possible. Sliding windows are a little less forgiving as the glass is sliding in a channel in the frame and if the frame is bent, the glass will bind or grind on the edges of that channel and tear the draught felt out of its position. The trick here is to place the window in the hole flat, slide the window back and forth while bending the window to the boat shape. When resistance is felt, you should back it out until little or none is apparent and then fix the window at this point. Check the gaps at the two ends, adjust things so that this gap is uniform and then cove the adhesive to fill these. If this gap is too big, ie: 10 -15mm then the cabin side should be faired or rebated to provide the correct landing for the window to sit against. Badly fitted windows detract from the quality of your boats final appearance, and can limit their longevity drastically. 

If in doubt, ask.

We're here to help and do not mind going over these points as many times as it takes to ensure a proper installation job is done. If done properly, your windows will perform and last to their optimum.

Please call us with any questions you may have.