Replacing portholes for better in 10 steps

Portlights are essential for the crew well being. They provide lights, ventilation and a view. But it comes sometime with issues. Water leaks, crackled glass, broken knobs, aged aluminium frame or Stainless Steel with few peckles.

Rutgerson portlights are noticeable by their outer frame in deep-drawn marine grade stainless steel (316L) with a mirror-polished look. To make this possible, they use a multiple step forming process which keeps the dimensions within tight tolerances compared to the bent extrusion that bulges in the corners. Larger tolerances can lead to potential leaks. Another feature is the nuts on the frame are spin welded. Such friction welding directs heat input at the weld interface and yields relatively small heat-affected zones, thus mitigates potential corrosion.

Also, a critical design element is the seal between the acrylic glass and the frame. The common materials used by other brands are cellular rubber or compressible foam. The problem with those materials is their tendency to disintegrate over the years.  It will set under compression leaving room for leaks and for the UV rays to dry them. Rutgerson’s seal is a highly durable silicone rubber gasket, like the automotive window seals, which is integrated into the acrylic glass in a groove. The acrylic glass is also thicker compared to other brands, which leads to better insulation and noise reduction. The acetal knob design allows adjustment to the closing pressure.

For someone planning to refit their boat, they will notice the availability of different shapes and sizes and that the Inner frames are always included. Another interesting fact are current Lewmar Size 2 Standard models and 250mm round portholes are interchangeable with a Rutgerson. For those planning for blue water sailing, all portlights are CE approved for ocean category A in Area 1.

Replacing or installing a porthole is not that complicated.

First step is to use the templates and position it where you want your opening. Mark the exact location of the hole to be sawn, using the paper template or the aluminium template.

A trick is to place Scotch tape™ on the surface to be cut to prevent it from cracking, then using a jigsaw, cut out the hole. If you see exposed balsa core, some will recommend to glass it or cover with an epoxy paint.

When the hole contour is cleaned, take the porthole and apply a generous amount of sealant or use a butyl tape on the inside gutter of the outer frame.

The sealant compound should be used in accordance with the manufacturer’s instructions. We recommend butyl as silicone overtime keep is cured shape, and butyl conform the any porthole movement. Also, note that excessive sealant can easily be removed after for butyl, and within few days when others the sealant has cured. 





Just before installing the porthole in its position, measure wall thickness and cut the M5 DIN 84-A4 bolts to the same length. Remove barbs at the tip made during the bolt cutting process.

Mount the portlight outer piece and the inner frame on the hull by fastening the bolts. Apply a lubricant on the bolts at the maximum torque of 2,5 Nm (1.8 lb-ft). Do not over torque but you might need to re-torque later as the sealant will spread.

When done, cut the decorative frame to the required depth using a saw and remove the barbs with sandpaper. It is important to have the Velcro™ touching the inner frame.

After test fit, clean the inner frame with acetone or alcohol. Remove the protection tape from the glued surface on the Velcro and press the decorative frame into place. Velcro™ glue is pressure sensitive. Apply a light pressure to ensure contact for a minute or two.

Refrain from removing the inner frame for a few days to ensure that the glue on the Velcro has set.

Now you can enjoy a cabin with a view!