Adding ports to the cabin

[ChrisAndVero]

I have lurked here for months, and know there are people on here _much_ smarter than me. I have a question for yous

We have a 1971 20' Balboa. While a very fun boat, we have found the interior to be rather dark. The 2 ports on the sides of the cabin are original (as is everything else ) and the clear is not so clear anymore. Replacing these would add some light, but I would like to add _more_ light as well.

One idea I had was to cut two new ports on either side of the forward cabin (it is slightly angled into two planes). Into these I would put acrylic panels that are cut to fit smoothly with the exterior but have a 1" lip all around on the interior. Seal and bolt these in place with a dozen 1/8" s/s bolts and washers. Assuming i do not screw up the cuts and find a shop to make the panels properly, this would give a smooth exterior (like the pretty new boats I see at the shows), and double the light coming into the cabin.

BUT...

Will this have an impact on the strength of the cabin top? the deck-stepped mast does have a support pillar beneath it, but this is a 20' boat. We (and guests) walk all over it! Is there minimum thickness that would do the trick? I was thinking 3/8" + or - 1/16". This is all armchair engineering so far, but i want to get a good sounding before I even think about cutting holes in my boat.

Thanks in advance.

[mike dryver]

every hole you put in the side of your cabin weakens the struture. that is a natural. this does not mean you cannot do it. you have to be aware that you are taking strength away from the original layup of the boat. the bigger/longer the holes you cut the greater the loss in strength. you just need to use common sense. have you explored the idea of putting a hatch in if poss. forward of the mast. this will give lots of light and you can open it for ventilation, you just have to make a frame work for it to sit on. there was an article in d.i.y. mag on this last/this issue.

[sailingdog]

Also, a better idea might be adding a deck prism, rather than cutting out ports. A deck prism will add quite a bit of light, and requires a much smaller hole be cut into the cabintop.

The acrylic panels, if you decide to go with the ports, should be exterior to the opening, so that they are supported by the cabintop, rather than being supported by the screws only. It would be far more secure that way.

Any openings you cut will weaken the cabintop to some degree. If you use a framed opening, that can reduce the amount the cabintop is weakened, much like the framing of a door in a house.

[ChrisAndVero]

Thanks all! I will look into the deck prism, and my wife was happy to see her plan of installing a clear hatch cover vindicated (we do have a forward hatch). And last week I noticed an acrylic manufacturer just down the road...

projects, projects!