I am seeking info or recommendation on material selection and fabrication of some spacers.
Our 35 yo portlights
, no great shakes to start with, are giving up the ghost. Lord only knows their make. Some are heavily corroded and compromised, they need to go.
I found Vetus units (PM-141 CE-A1) that fit this cut out, but the cut out is a bit rugged. I am not sure of the tolerance requirements for the Vetus lights but have read (on CF) they want 1 mm tolerance. The new units have a narrower bezel and do not bolt through the steel
. This means the old bolt holes will be partially exposed. Inside there is a 1/4” ply backer to the steel
. The corrosion
took place where the inner ring touched the wood
. They cabin
wall is 4mm thick, the lights will accommodate up to 1” thickness. The lights clamp to the hull
, no drilling required. I have 2 lights on order for a trail, should arrive this week. Need 12 altogether. 2+10.
The exposed holes are a problem. I could fill them by welding them shut. PITA. But I could also have a 1/8” spacer made that covers these holes. Tuis spacer would be outside of the hull
under the lights rim.
Inside I may need an additional spacer, between the wood
and the interior
rim. This would give the lights rim a more firm basis to clamp onto.
1: What is the actual, practical tolerance for a Vetus portlight? PM-141 Vetus gives no guidance but says to cut out with an oxyacetylene torch. (Yikes)
2: Comments on the outer ring material. I was thinking first some grey polypropylene because that is what my Porta Boat
is made from and it seems totally impervious to UV. Better options? However I could use aluminum
, get it CNC cut.
3: Comments in the inner ring material. Similar to above; plastic or aluminum
4: Do I even need an inner ring would the wood be good enough? I am leaning away from this because of past corrosion
where the aluminum contacted the wood.
5: Regarding existing corrosion. I had the lobster guts out a couple of hears ago, cleaned them and rebedded. My only thought is that when I cleaned the inner ring of the existing lights I removed some kind of protective coating (anodizing?) that allowed them to corrode when reinstalled.
Any other comments or advice
would be appreciated.
Remember: steel boat
, Vetus is the only one (I can find) that marches the existing cut outs.