Underpinning and rivet size

Chris Deel

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I am wanting to install a second amplifier and some tower speakers on my 2021 Bennington. Problem I have Is the underpinning doesn’t allow me to get to the wiring that is already in place from the battery to the helm. I thought about removing some rivets and taking down a panel of the underpinning but the drill bits keep breaking and I can’t tell what size rivet I need to replace them when I’m finished. Also it seems the underpinning may be glued along with the riveting. Does anybody know if it is glued for sure or what size rivets I need to replace the ones stock. I know it’s 3/16 head but not sure what grip size I need. Thanks for any help.
Chris
 

Vikingstaff

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I am wanting to install a second amplifier and some tower speakers on my 2021 Bennington. Problem I have Is the underpinning doesn’t allow me to get to the wiring that is already in place from the battery to the helm. I thought about removing some rivets and taking down a panel of the underpinning but the drill bits keep breaking and I can’t tell what size rivet I need to replace them when I’m finished. Also it seems the underpinning may be glued along with the riveting. Does anybody know if it is glued for sure or what size rivets I need to replace the ones stock. I know it’s 3/16 head but not sure what grip size I need. Thanks for any help.
I know there are some in here that have done similar work in removing and putting back on the underskirting. Hopefully they will speak up. If not, try calling a Bennington dealership service department and asking them these same questions. They would have to know, and could share what they use/do when needing to removing and reassemble someone’s Bennington underskirting.
 

sunedog

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Do you HAVE to remove the underskin? Several on here have completed wiring projects or run new transducer cables with it in place. I haven't, but I recall some have used those fiberglass rods that screw together to fish the wires. (I think you can get them at Harbor Freight.) You may have to remove the side skirt (trim between the deck and the toon).
 

Chris Deel

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Yeah I’ve read something about the side skirt and it being a pain to remove. I looked at that but couldn’t see all the bolts holding it on from start to finish. I heard some say that few of them were inaccessable but somehow everyone figured it out. That may be the way to go. I’ll take a look and see if I can figure it out. Wish I had a video or pictures. Anyone with experience taking them off, I would appreciate the advice! Thank u!
 

lakeliving

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I took the side skirt off mine for trolling motor cables. Easy bolt off and on. I’d go that route if I was you. Nice to work from the side vs tucked under the boat too
 

Potomacbassin’

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I am wanting to install a second amplifier and some tower speakers on my 2021 Bennington. Problem I have Is the underpinning doesn’t allow me to get to the wiring that is already in place from the battery to the helm. I thought about removing some rivets and taking down a panel of the underpinning but the drill bits keep breaking and I can’t tell what size rivet I need to replace them when I’m finished. Also it seems the underpinning may be glued along with the riveting. Does anybody know if it is glued for sure or what size rivets I need to replace the ones stock. I know it’s 3/16 head but not sure what grip size I need. Thanks for any help.
Chris

Just tackled a project today, wanted to add this for posterity. Here is a new rivet next to the steel one that was drilled out. This rivet was on some thinner frame elements so a 1/8 - 1/4 works. There are other rivets that are secured to the thick cross member where 1/4 might be too short, but no idea since I bypassed those.

As far as the glue question, from what I could see when pulling on the panel it's double-sided tape.

70D5CAA8-4883-4C59-8FF1-61EB4D915D5E.jpeg
 

dannyleininger

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I thought the rivets were Stainless Steel. At least that is what my dealer told me. But I can‘t imagine why Aluminum wouldn’t work.
 

Potomacbassin’

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I thought the rivets were Stainless Steel. At least that is what my dealer told me. But I can‘t imagine why Aluminum wouldn’t work.

Correct, the ones I drilled out were steel (stainless). Absolutely destroyed my standard bits so I need to upgrade to a cobalt set.

My dealer uses an air tool to cut the heads and then punch the sleeve out, but for just removing a few I think the drill option is fine. He also noted aluminum rivets are likely fine for boats that don't see a lot of pounding (slower boats) but for mine he recommended going back to SS once my project is wrapped up.
 
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