Mainship 350/390 railing questions

[mncruiser]

Howdy,

I've got a 2001 Mainship 390.

Currently planning to re-seal the bases of the railings, existing sealant looks to be degrading. Previous owner's yard did do all this back in 2017.

First question - What is under there? Meaning, the bolts from the top, are they screws, or bolts with nuts and backing plates?

Second, if they are bolts and nuts and backing plates, how do you get under there?

I have not taken anything apart yet, was hoping maybe one of us had done this before.

Thanks

 

[Gdavid]

The rail around the bow? We have found the mounts to be inaccessible. I suspect they were installed into the deck/cap molded section prior to joining the hull and deck. This was on the stainless rail, not sure about the earlier aluminum rails.

There was a slightly bent section, it was straightened in place.

 

[Cold Duck]

Not sure about the bow/side rails, but the handrail going up the stairs is just big wood screws. I just looked at them yesterday while in the bilge. Possibly the handrail for bow is the same.

 

[kthoennes]

I have a different Mainship, 1996 37 "Motoryacht" but I have exactly the same question. Our marina broke the stanchion welds on two of the bow rail vertical pipes during launch last week. The entire bow rail is one big continuous welded structure, and each base is held to the deck with two big phillips head -- screws? Bolts? I don't know. But I'll bet Mainship used the same approach. I haven't tried to remove any yet. I'm hoping they are big wood or sheet metal screws and not machine-threaded bolts with nuts I can't access.

 

[porman]

I don't know if this is worth much, but I had to remove a short section of side rail on our 2003 430. It was bent and didn't line up with the section in front of it. There is a gate between the two sections. The three vertical rails all had three screw flanges attaching them to the hull. Eight of the screws were machine thread and one was a lag screw. The nut plates for the machine screws were glassed into the hull. Later, when I was installing a hydronic heater and had access to the underside of the rail, I saw that they had probably glassed in backing plates and then drilled and threaded the holes. The hole where the lag screw was looked like they had slightly missed the location of the plate and there was no metal underneath to thread.

 

[Bacchus]

I don't know if this is worth much, but I had to remove a short section of side rail on our 2003 430. It was bent and didn't line up with the section in front of it. There is a gate between the two sections. The three vertical rails all had three screw flanges attaching them to the hull. Eight of the screws were machine thread and one was a lag screw. The nut plates for the machine screws were glassed into the hull. Later, when I was installing a hydronic heater and had access to the underside of the rail, I saw that they had probably glassed in backing plates and then drilled and threaded the holes. The hole where the lag screw was looked like they had slightly missed the location of the plate and there was no metal underneath to thread.

Tim
Thanks for confirming. I have wondered about rail fastening on my 2008 34HT since buying it. I know the swim ladder if fastened to the swim deck in similar fashoin... drilled & tapped w machine bolts. When removing & modifying I broke a couple and was able to Redhill, tap & install bolts in a slightly different location.
Thanks!

 

[mncruiser]

The rail around the bow? We have found the mounts to be inaccessible. I suspect they were installed into the deck/cap molded section prior to joining the hull and deck. This was on the stainless rail, not sure about the earlier aluminum rails.

There was a slightly bent section, it was straightened in place.

Yep, from the bow back right to the rear of the mid cleat.

 

[mncruiser]

I don't know if this is worth much, but I had to remove a short section of side rail on our 2003 430. It was bent and didn't line up with the section in front of it. There is a gate between the two sections. The three vertical rails all had three screw flanges attaching them to the hull. Eight of the screws were machine thread and one was a lag screw. The nut plates for the machine screws were glassed into the hull. Later, when I was installing a hydronic heater and had access to the underside of the rail, I saw that they had probably glassed in backing plates and then drilled and threaded the holes. The hole where the lag screw was looked like they had slightly missed the location of the plate and there was no metal underneath to thread.

It would be awesome if this was the case. I might have to find one of the almost accessible ones and remove a bolt/screw and see what’s there.

Thank you!

 

[Comodave]

The PO had broken a couple of the stanchions loose from the bases. I had to get them rewelded. My Formula had through bolted bases. So I had to access the nuts inside the boat. They were very well hidden. Had to cut some cabinet tops out to get to them. I taped a rare earth magnet next to the base on the deck. Then inside used another rare earth magnet to find the one on deck. It helped find the area to look for the nuts and backing plate before cutting into the headliner. Fortunately where I had to cut the headliner was inside a cabinet so it doesn’t show now. We took the stanchions bases loose and inserted a 1/2” piece of drywall under the bases so the fiberglass wouldn’t get burned. Drilled holes in the drywall for the bolts and inserted the bolts in to hold the bases in the proper orientation so they would line up with the existing holes. All in all it worked fine.