Cutting Hole in Bulkhead

[argus1]

On a 2011 330/350 Sundancer I need to run some wires from the hatch area up to the dash. On the starboard side there is a bulkhead right under the arch meets the side of the boat. Is okay to put about 3 inch hole in this bulkhead? After I cut a hole and run the wires, do I need to fill the hole in with 3M 4200 Caulk? This is what it looks like now. The wires there are what an electronics installer did previously. I need to add another hole. I want make sure that I an doing it right. As you see this is close the the fuel fill hoses.

 

[Henry Boyd]

I did the same thing to run the radar cable. Keep in mind that is sealed not only for strength, but also to isolate the ER fumes from the cabin area. If you cut a 3” hole you may need to find one of those rubber diaphragm like plugs.

 

[Spark600]

Can you just chop some foam out of the existing hole run your wires and seal it up.

 

[Henry Boyd]

Can you just chop some foam out of the existing hole run your wires and seal it up.

Huh? There is no existing hole. Op is going to cut a new one.

 

[northern]

When you cut a hole in steel beam that is over 1/4 the width of the beam general rule you must reinforce it. I have no idea if that rule applies to boats.

 

[argus1]

When you cut a hole in steel beam that is over 1/4 the width of the beam general rule you must reinforce it. I have no idea if that rule applies to boats.

Don't think this applies to boats; boat are full of holes. I think this bulkhead is to prevent engine and gas vapors from going forward to the cabin area. I think the consensus is that the hole should be sealed after the wires are threaded through. I plan to use 3M 4200 Sealant in the case the wire ever needs to removed.

 

[Henry Boyd]

Don't think this applies to boats; boat are full of holes. I think this bulkhead is to prevent engine and gas vapors from going forward to the cabin area. I think the consensus is that the hole should be sealed after the wires are threaded through. I plan to use 3M 4200 Sealant in the case the wire ever needs to removed.

Beams, particularly I beams, unevenly support the load. The flanges carrying the actual load with the purpose of the web to hold the two apart. A round hole in fiberglass that is sprayed chopped strand like sea ray hulls, supports the structure uniformly. Granted the hole should only be as large as it needs to be, but there should be no issues as long as the piece isn’t completely bisected.

 

[Lazy Daze]

FYI, 4200 is way overkill for this application and really doesn't do anything "extra". Just use a tube of silicone from HD. You don't need the "strength" aspect of 4200 here.

 

[Nauti-Kal]

4200 Caulk? This is what it looks like now. The wires there are what an electronics installer did previously. I need to add another

 

[argus1]

Measure twice and cut once. I only needed a 1½" hole to get the wire bundle through. Glad I realized this before I cut the hole. The bulk head has a plywood core with a very thin layer of fiberglass on both side which means it needs to sealed well to protect the plywood core.