Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
MattFL
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Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby MattFL » Sat Sep 23, 2023 12:07 pm

Q1; What is the best way to fix enlarged rivet holes under the rubrail of a 1996 Montauk [17]?

Many of the rivets have pulled out of their holes and replacing them with the same size rivets will not hold. The holes appear to have been enlarged and are a bit ragged--as can be expected for a boat [whose age is now 27-years-old]

I have injected epoxy resin into the holes. [When the epoxy resin cures, I have been] drilling [new holes] to the original size then putting in new rivets.

I believe that a more durable method [of repairing the enlarged holes that retain the rivets that retain the rub rail on a 1996 MONTAUK 17] must exist.

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Phil T
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Re: Best way to repair enlarged rivet holes - 1996 Montauk rubrail

Postby Phil T » Sun Sep 24, 2023 10:38 am

The recommended approach is to fill the old holes and drill new holes for the rivets, not to reuse the same holes.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
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Re: Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby jimh » Sun Sep 24, 2023 5:48 pm

I agree with the advice from PHIL T. There is no particular obligation that the location of the rivets MUST be exactly where they were in the original construction of the boat. Moving the rivet locations an inch or so away from the original location seems like a perfectly suitable approach to installing new rivets into new holes.

Don SSDD
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Re: Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby Don SSDD » Tue Sep 26, 2023 7:19 am

I used beveled head Robertson stainless screws instead of rivets for this, bedded with 3M 4200, after drilling new holes. The screws are much easier to install in a tight fashion with more control over the process than with a rivet. Screws are also easier to remove in future than a rivet. If you don’t have Robertson screws in your area, a Phillips is likely available.
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

MattFL
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Re: Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby MattFL » Tue Sep 26, 2023 7:38 am

Thanks all, I might end up doing what you all suggest and put holes in new places. I can take the opportunity to replace the entire rub rail with a new one, properly plug the old holes and make new ones. But to put new holes in the boat hurts.

jimh
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Re: Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby jimh » Tue Sep 26, 2023 10:17 am

ROBERTSON square-tapered-drive fasteners are very common in Canada, but practically never used in the United States. The Phillips-head fastener is a better choice because it cannot easily be over-tightened. This will prevent the installer from stripping the self-tapping screws in the relatively thin laminate structure of the hull where the rub rail attaches.

Don SSDD
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Re: Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby Don SSDD » Tue Sep 26, 2023 8:16 pm

The marine guys in the Maine/New England wooden boat side have been using bronze Robertsons for a while now. Home Depot sell them in the US, not sure if all over.
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

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Phil T
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Re: Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby Phil T » Wed Sep 27, 2023 9:40 pm

The Robertson fastener is commonly referred to as the square bit screw by the trade guys in the States.

Their use is very common in residential construction.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
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Re: Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby jimh » Tue Oct 03, 2023 3:55 am

Again, I see no reason to use a very high-torque fastener for securing the rub rail. The chances of stripping the treads in the laminate will increase compared to using the more common Phillips head screw.

WillVan
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Re: Repair Rivet Fastener Holes in 1997 MONTAUK Rub Railing

Postby WillVan » Sun Nov 26, 2023 11:34 am

If the original specified fasteners work fine, why change them?

When the bow rail base screws get loose, don't substitute a larger screw. Fill the hole with epoxy with a little thickener and some glass fibers, re-drill the hole, and refasten. Take the opportunity to reseal the holes with 3M5200 adhesive sealant.

Here, the original Pop-rivets are fine.

[Compromised] fastener holes can be relocated if installing new rail, but fill the old holes with resin and some reinforcing fibers. The laminate here is very thick in this direction, which is why long two-inch rivets are used. There could be small voids between laminate layers here where top and bottom skins are stuck together and the expanding rivet body adjusts to that.

If only refastening one area--as when the rail gets smacked from collision--just drill out the rivets, fill old holes and re-drill there or alongside.

On our latest Whaler, an 1985 Montauk, the previous owner installed a rub rail replacement kit himself, and we're paying for it. And that's not to mention grinding off stuck-on L-trim. He used pan head stainless steel self=tapping screws, and the screw heads interfere with good seating of the [rub rail] insert, making it bulge in places. And to route navigation lamp wiring along the port side is now harder [due to the fastener heads].

Use flathead screws instead and countersink?

Why bother?
Brunswick, Maine
Whaler #6:
1985 Montauk
2005 Evinrude 90 ETec