Swim Platform Brackets Pulled Loose

[Vincentc]

I hauled out Lilly Marie (43 DC) yesterday, and discovered that the bottom bolts of about 4 of the 6 stainless steel swim platform brackets had pulled out from the transom and one of the brackets welds had separated.

The weld separation involves one of the center brackets and is located at at the bottom of the bracket where the diagonal pipe attaches to the bottom of the bracket.

At the lowest point of those brackets they are about 1/2 inch from the transom. If I pull down on the platform the bottom of the bracket goes back against the transom.

I did not have much time to study the problem yesterday and will give a more detailed report and post a photo later today, but I am puzzled as to how and why this happened. I do recall an incident last summer where we were anchored overnight and the weather got kind of bad. I recall hearing the swim platform hit by wave action as I tried to sleep in the aft cabin. The boat did a lot of "hobby horse" movement that night/morning and the inflatable dingy apparently got under the platform because it suffered a tear in its fwd compartment.

Last haul out, Jan 09, I discovered that one of the bottom bolts was simply bedded in place with caulk but the brackets were not pulled out from the transom as the are this time. At that time I thought I fixed the problem, but believe that I focused on the upper bolts since I assumed that they would be under the greater load.

The platform otherwise appears to be secure. There does not appear to be any issues with the other 3 bolts on each of the brackets.

Has anyone had a similar experience with these bolts/brackets?

Regards,
Vincent

 

[SKYCHENEY]

My brackets were bent, so I made new ones out of stainless channel. The bolts go into threaded aluminum plates that are glassed into the inside of the transom. Drill them out and retap to a larger size.

I notice the platform on our 1985 53 is much higher off of the water than our 1975 43DC. On the 43 we would occasionally get some wave action in the marina and they would hit the underside of the platform. It sounded like a drum as it echoed through the boat. Not great for sleeping in the master with that going on. I rarely, if ever, have that with the 53.

 

[bobk]

I got caught in Dowry Creek marina a few years ago when some strong winds were blowing in. The stern was to the waves, and the constant hammering under the platform managed to break bolts and wear open bolt holes in the channel iron mounts. A couple of the lower 'bolts' turned out to be lag bolts that went into the back end of the stringers. If there was a plate molded in, we didn't detect it when drilling out for a larger lag bolt.

Bob
Chateau de Mer
1981 48MY

 

[Vincentc]

Interesting about the difference in platform height. Sounds like a reason to trade up, on the other hand I can get out of the water without a ladder.

 

[REBrueckner]

One year at haul out I also found a broken weld as you describe. I have no idea what caused it but stainless welds seem to have some irregularities.
The flat stainless supports are not the best shape for strength and rigidity. I would have prefferred a U shape or angle shape support piece was used.

It's also possible crevice corrosion is an issue here, mainly the bolts. Perhaps Hatt got some with an irregular alloy or maybe the bolts were changed at some point in the past.

 

[Genesis]

I never had problems with the brackets (same design you're talking about here) but I did nearly rip the platform off the boat by pulling the bolts through the fiberglass of the platform.....I probably deserved it as I was backing down HARD on a fish when I did it. It was repairable without too much trouble but was destined to happen again in similar circumstances, and I really didn't want to wind up making the platform attachment strong enough that I'd rip the brackets off instead leaving holes below the waterline.

Eventually I pulled the platform off the boat.

 

[Vincentc]

Thanks for the comments.

Glad to hear my problem is not unique. Until now I never gave it much thought, but the force of the water upward against the platform is more that the force of a few people standing on the platform. Impressive to see what that force can do
Regards

 

[bigbill]

vincent, check the inside of the boat BEFORE you start drilling...............there might be a tank or something mounted against the transom. i am not familiar with your model boat, but, my 58yf has a tank mounted to the transom.