Porthole measurements

[Publius]

Okay so I am trying to create 6 new ports on Reprisal.  Three on each side, two aft one forward. 

How do I determine the best aesthetic and functional resting place for the ports?  Should they rest with the bottom edge parallel to the ground or parallel to the bottom of the hull (that is to say potentially on a slant).  Is there a way to guarantee symmetry with the ports on the opposite side of the boat?  Does any one know a good supplier of port frames?  The color of the hull will be blue, would a bronze or chrome type color be better?

I was thinking of creating a port for the head as well, while my thoughts for the other ports were to make them oval or soft rectangular in shape, the head port I was thinking should be circular.  I also plan to have a solar powered vent above the head, do I just punch a hole through where I plan to position the vent?   

What is the best tool to use for cutting out portholes?

Thanks for your time and help!

[AdriftAtSea]

Okay so I am trying to create 6 new ports on Reprisal.  Three on each side, two aft one forward. 

How do I determine the best aesthetic and functional resting place for the ports?  Should they rest with the bottom edge parallel to the ground or parallel to the bottom of the hull (that is to say potentially on a slant). 

I would take a good photo of the boat, from the profile, and then play with it in a photo editing program to get an idea of what shape and location you want the ports.  Be aware that cutting openings in the hull does weaken it, and you generally want to do something to restore some of that strength when installing the port. 

One option is to go with framed ports, where the frames contribute strength to the cabintop, passing stresses across the opening.  Another method is to reinforce the cabintop around the port openings, similar to sistering the studs alongside door or window openings in a house wall.

Is there a way to guarantee symmetry with the ports on the opposite side of the boat? 

Yes, use full size templates and be very careful when placing them and measuring their location. :) Cardboard or posterboard templates can often be used for both sides, since they're flexible enough to bend in both directions. A friend of mine made the templates out of 1/8" HDPE or ABS sheets, since they were far more durable that way...

Does any one know a good supplier of port frames?  The color of the hull will be blue, would a bronze or chrome type color be better?

Most companies don't supply frames.  They supply the entire port.  I would go with white, if you're going with plastic frames, and bronze if you're going with metal, especially on an older design boat—but chrome/stainless steel might look better if the hull is blue. :)

Beckson ports were OEM equipment on many boats, but aren't the strongest ports around, since the less expensive ones are plastic framed.  I used one for the opening port I installed in my cockpit.  It also doubles as an instrument panel. :)  See the photo below:

I was thinking of creating a port for the head as well, while my thoughts for the other ports were to make them oval or soft rectangular in shape, the head port I was thinking should be circular. 

Do you want the ports to be deadports (non-opening) or portholes (opening).  It's a personal choice... but having them be opening ports makes the boat far more comfortable at anchor.  However, it increases the chances the ports will leak. :)

I also plan to have a solar powered vent above the head, do I just punch a hole through where I plan to position the vent? 

Pretty much... I prefer the Nicro Solar Powered Vents. Get the 4" not the 3" as they move twice as much air.  The ones I got were the high-end ones, since discontinued, that had metal deck rings and the vents can be unscrewed and replaced with deckplates, in case you're sailing in really horrid conditions.  The newer ones have a plastic collar or something of that sort that allows you to close them off fairly well, but green water over the cabin top would probably still get some water through them. 

What is the best tool to use for cutting out portholes?

Thanks for your time and help!

Usually a jig saw is the best tool to use.

[Publius]

The photoshop idea is GREAT! seriously i cant believe i didn't think about that.  And a full size template sounds like an excellent symmetry solution (plus back up measurements after tracing the holes).

I definitely want to use frames.  The head port must be opening, the others could be deadports. I am debating.  Personally, I'd want them to be opening for the reason you listed and even not at port in calm conditions.  However I have been advised by others on this forum that could be a dangerous idea (leakage etc).  What is your opinion? Perhaps there is a way to insure water tight seals? Or a water tight porthole when shut?

[mrb]

One thing to think about when planning ports is the curvature of the location of ports.  In other words if you are placing a 10"x8" port that has a flat frame you will need to find a location that is flat in both dimensions plus a few extra inches in each direction.  Use a straight edge such as a carpenter square to check for flat areas.  You may get away with a little curvature of the hull but try to keep it to a minimum.  On dead lights with plastic frames you may get away with more curvature. on metal frame and opening ports you wont get away with bending frame to fit curvature.  That is why there were a lot of small round opening ports on older vessels.

Use a good polysulfide caulk and apply it in a couple of beads, one inside bolt ring and one outside bolt ring.  Of course dry fit everything first before applying sealant.

For ports on hull sides buy the best you can with good dogs.  Hang them with hing up.  Mark cut lines once and check twice before cutting.

Use a good jig saw with best blades you can find.  Also use top quality drill bits, Don't want them to walk on you.
Good luck

[Publius]

ok mrb will make sure the surface is flat thanks for the tips

ill be putting pictures up of where the ports will be soon.  might be tough to find a flat area on the v birth, there is a lot of curvature

some one suggested that the forward hatch might be enough ventilation and that v birth ports are unnecessary.  I would like to have them i feel, just for aesthetic appeal and also to be able to see the sea from the v birth.   thoughts?

[AdriftAtSea]

A good compromise might be to make only one of the three on each side an opening port.  That would allow you to have some ability to compensate for ports in non-flat areas of the cabintop, since non-opening ports will generally work fairly well on slightly curved surfaces...but opening ports generally need flat surfaces.

If you make opening ports, it is generally a really good idea to make storm covers for them.  Design them with provisions for attaching the storm covers in mind when you set them up from the beginning to make your life easier.

Butyl tape will often work to seal ports, and in many cases will work better than caulks, since the butyl tape tends to stay soft, elastic and sticky for a very, very, very long time.

[mrb]

If you are lucky enough to live close to a marine store go there and look at some of the ports they have available.  Find some you like and take measurements of some large ones and diffrent sizes down to small fixed ones.  Then make up some templates out of stiff material and start sliding them around the area where you want to put a port.  In an area like forward toward the v berth area you may find one of the small ones just happens to fit.  

The book I listed above gives some ideas about dead lights in the deck.  You may be able to adapt one to your area.

You have two things going for you now.  One, enthusiasm and two, a clean slate to work on.  

[CharlieJ]

What is the best tool to use for cutting out portholes?

What I do is make a plywood template of the porthole, usually using the trim ring as a pattern. Drill the holes using the port as a guide. then tape that in place where it needs to be, drill the two end holes and bolt it down. Then I use a trim router with a pattern bit to cut the opening- using the ply as the guide for the bit. Use the holes you drilled as guides and drill through the cabin sides ( or whatever). Then ALL of the openings will be identical and the ports will fit ALL of the openings.

Oh- and check with the Beckson web site- they recently had opening ports on sale ( an overstock) for 40 bucks each. Might be sold out, but they always have a list of overstock sale items.

Of course I MUST add I'm still opposed to the idea of opening ports in the topsides of a boat as small as one we are discussing. Cabin sides, yes, cockpit sides into quarterberths, yes- topsides ( hullsides) no.

[AdriftAtSea]

I'd second his recommendation to look at the Beckson site. :) Some of the bargains they have there are very good.

Oh- and check with the Beckson web site- they recently had opening ports on sale ( an overstock) for 40 bucks each. Might be sold out, but they always have a list of overstock sale items.

I'd never recommend putting opening ports in the topsides on a boat this size... even on bigger ones, it isn't a very good idea, unless they're multihulls, since monohulls tend too heel and the ports can often end up submersed temporarily... and most opening ports don't seal well enough to deal with that kind of treatment on a regular basis.

The Cabintop and interior of the cockpit are a different story. 

Of course I MUST add I'm still opposed to the idea of opening ports in the topsides of a boat as small as one we are discussing. Cabin sides, yes, cockpit sides into quarterberths, yes- topsides ( hullsides) no.

[Auspicious]

What is the best tool to use for cutting out portholes?

The best tool is a oscillating or vibrating cutter. There was a time when the Fein Multimaster was the only choice, but it appears that some patents have run out since there are a number of alternatives. Dremel ( http://www.dremel.com/en-us/Tools/Pages/ToolDetail.aspx?pid=Multi-Max ) makes one that is available for well under $100.

[CharlieJ]

Yep- IF you are cutting straight lines or gentle curves. But for cutting several openings, all just alike, I'd opt for the router and pilot bit with a ply pattern EVERY time. That's the ONLY way you can make sure all are just alike. At least for me.

[Publius]

okay thanks guys, will be checking out the beckson site

the ply template sounds like a good idea.

no marine store near me (philadelphia) but I will look around

(pictures to come soon)

[Auspicious]

What is the best tool to use for cutting out portholes?

The best tool is a oscillating or vibrating cutter.

Yep- IF you are cutting straight lines or gentle curves. But for cutting several openings, all just alike, I'd opt for the router and pilot bit with a ply pattern EVERY time. That's the ONLY way you can make sure all are just alike. At least for me.

Definitely agree. I think I'd use a veneer bit; what do you think?

The jig saw is not a great idea.

[CharlieJ]

Well, what I use is a "patterning bit". It has a ball bearing on the router side that rides against the pattern edge. The cutter part is away from the router. You bore a hole just larger than the bit, put the bit through, crank up the router and just follow the pattern. A "veneer" or formica bit usually has the guide part AWAY from the router, so it will follow the substrate. But you can't see the pattern then. I prefer working from the pattern side. Matter of preference I guess.

[Publius]

ok that sounds like a great method

is it just me or are stainless steal port frames very expensive?!

..and hatch covers

[Amgine]

Everything which doesn't have an application ashore is expensive. That said, stainless ports do seem a bit higher than they should be though. Have you considered other materials?

[CharlieJ]

You think stainless is expensive? HAH!!

Try finding some opening BRONZE ports that are affordable!l Or at least affordable for an old retired guy like me :D

I'm searching for two small opening ports to put in the forward cabin of Tehani. I refuse to use plastic, since everything else is bronze.

[Amgine]

Hmm, they're the same prices at New Found Metals, which surprised me. Spartan are nearly twice the price it seems, but then they're hooded type. Lunenburg Foundry used to have excellent prices, but they no longer have a catalog online nor do they list their prices anywhere. ABI doesn't sell direct, but the online prices are very high (see MMO for round or rectangle.)

Yep, better thee than me. I can't afford new portals.