Deck Prism......photos?

[Cruiser2B]

I am in the process of refitting my Alberg 30. I am about to start on the decks and recoring job. I have considered adding a deck prism or two the the topside decks.

The obvious drawback is a hole in the deck that can be prone to leaking. But my Alberg is a bit dark below and want to add some natural light.

Do any of you have them, if so how do you like them and what if any are the associated issues? Can you post a photo of your application?

Thank you

[sanibel sailor]

Don't have one, but they work great- if you have never seen one in action, you will be surprised at the light. Main downside for me is cost. I have not found a cheap source for what seems a very simple item.

[Steadman Uhlich]

On the boats I have been on that have deck prisms, I have always thought they were a nice addition. But, if putting a hole in a deck, I think adding ventilation would be my first priority. For that I would add a Dorade vent (or several). After that, I would consider additional flat hatches that open (more light, more ventilation).

[Target9000]

We have two. They are notorious for leaks but after bedding in butyl rubber we've had no problems. In hot weather they let in a lot of heat so you need some way to cover them. We use a board while at anchor.

[Cruiser2B]

Originally Posted by Steady Hand

On the boats I have been on that have deck prisms, I have always thought they were a nice addition. But, if putting a hole in a deck, I think adding ventilation would be my first priority. For that I would add a Dorade vent (or several). After that, I would consider additional flat hatches that open (more light, more ventilation).

Thank you, I am also adding more ventilation, pretty sure I have that covered. I am adding a few small hatches(lewmar 10 ocean series) and 2 forward facing opening portlights identical to that of Pearson Triton in the same location. My Alberg 30 and the Triton are near identical.

[Cruiser2B]

Originally Posted by Target9000

We have two. They are notorious for leaks but after bedding in butyl rubber we've had no problems. In hot weather they let in a lot of heat so you need some way to cover them. We use a board while at anchor.

Good info, Thank you. Where on deck are our prism located?

[Target9000]

On either side of the main cabin. One is over our table the other is over the settee.

[Tayana42]

I have 6 prisms. They add a wonderful amount of light. This first photo is under one prism in an otherwise dark quarter cabin.

Ours lasted 26 years before leaks. They are bedded in a black something like Life Caulk. I've just started replacing them. The leaks were not around the bedding but rather in the silicon that glues the plastic prism into its aluminum frame. The next two photos are an original prism and then a replacement. notice the plastic prism is breaking down after 26 years in sun and salt.

Here is a below deck view. . It was hard to get detail in the strong light against the dark background. The inside finish is a plastic piece that may have been ordered from the same supplier.

Problem is these prisms were made by Bomar. Pompenette, the dealer for Bomar told me they haven't been made for years. Fortunately for me Ta-yang Shipbuilding the builders of Tayana boats knew exactly which parts had been put in my boat and that had some new old stock that they shipped out the next day. I got enough to replace all 6 of mine. Two done four to go.

If I were looking to put in deck prisms and not limited by the existing holes in the deck I would choose prisms that are clamped to the deck by their metal frame not ones that are glued into their frame from above. I'm told this type of structural silicon is what holds plate glass onto skyscrapers but I'd prefer a bolted metal frame.

Overall I would recommend the use of deck prisms to increase light below. Measure carefully, cut, seal the deck core well, bed carefully and you are good to go.




S/V B'Shert