Aft Deck Rail Reinforcement

*This is an important fix. If water is left intrude into this deck, you will be subject to the notorious Mainship Tea that has plagued the earlier lines from this and many other manufacturers. Check it out!

On the aft deck of the 400, Mainship has provided a raised mounting pads for the safety rail that surrounds the deck. I haven't noticed any problem with those mounting points yet and I assume they were formed with thickness and backing for their intended purpose. On Stella Blue, the end of the rail surrounding the stair case hole, is not affixed the same way. That end is screwed down into a very thin deck laminate without proper backing. I noticed a problem after the first rain when the boat was moved outside of the showroom. Water was entering and collecting on the entertainment cabinet over the refrigerator. The dealer could not find the source of the water, so I took delivery any way, and hoped to find the source over the boating season. (Be advised that the railing is mounted by the dealer, and not the factory, so there may be differences from boat to boat.)

It soon became obvious, after watching people use the railing coming and leaving the deck, that the base was loose. It could not be resealed and tightened due to the very thin fiberglass, that allowed the screws to strip out. Because on the thin flange and large flat head screw, there is almost no thread under the head to engage the thin fiberglass laminate section. Thru bolting would be very difficult because of the location and access from the backside. The flange is square to the rail stantion but that makes it far from flush with the sloping deck. Hopefully, Mainship will incorporate a mounting pad similar to the other pads, on future models to solve this problem.

This picture shows the failure of the bedding agent
where dirt and water entered the laminate and then
into the cabin entertainment center, where I first
detected the leak.
This picture shows the difference in the angles of the
mating surfaces a little better. in it's relaxed state there is about 1/4-3/8 " between the two so making a wedged spacer was needed.

What I decided to do to fix mine, is to make an over sized, stainless steel adapter base (4" diameter), with a wedge shape to accommodate the mismatch between deck and flange, bed it with 5200 and secure it with twice as many screws, then fasten the rail flange to it with 1/4-28 stainless steel machine screws. I'm a machinist, so making the base out of stainless was not a problem, but other materials such as starboard might work just as well with some changes in design. Below is the finished project.