Gunwale wall structure

M

marlinmikea

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exMember
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Jul 14, 2009
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31533
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I have a 1997 Mariner 350. In the cockpit, the gunwale walls have 5" holes cut in them for access. I am mounting a few things to the gunwales themselves (downrigger mounts, pole holders, pop-up cleat) and was wondering about what you thought about drilling another 5" access hole - closer to the aft to get a little better access to backing plates and through bolting. The fiberglass is about 1/2" in these areas and it doesn't look like it would jepordize the structural integrity of the boat, at all - well maybe of something a couple thousand pounds were to drop on the gunwale, but I think I'd have a few bigger problems if that were to happen. There is a screw on "hip cushion" that goes over these holes and really, not a big deal if a little water gets in there anyway as it'll just go down into the bilge. Besides - my pump need something to do :o)

What do you think?
 
lots of people cut holes for access plates in gunwales but pics of the area with proximity to other access plates would help.
 
Thanks for the bump Pete. btoran, that's EXACTLY what i was putting my shoes on for. Going to the marina to see if I can't get some pics of this to post.
 
Some photos I took today. The photo of the existing hole with the tape measure shows in inaccurate reading of the thickness of the fiberglass - i think because of the angle of the camera. I put the tape there to show some definition to the hole. The fiberglass in this wall varies, but is about 1/2" thick.
Just to get an idea of the strength of the fiberglass I put all my weight on one foot on the top of the gunwale over the existing hole and pressed up and down and noticed ZERO flex in the fiberglass. Because the holes are being spaced about 12" apart I think the horizontal, vertical and shear structural integrity of the inside gunwale walls aren't being overly compromised - unless I'm missing something.

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Structurally, a circle /arch / dome will be very strong, I think you'd be OK. I would take a flashlight and mirror to see what is behind your new hole before you start cutting.
 
i'm no engineer, but it will probably be ok. if it were me, i'd have prefered the holes to be a bit lower.
 
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