Removable Swim platform - need help

[The-strikes]

I have almost solved the problem of how to put a swim platform on my 2001 . I removed the ladder and made a plate that is cut out to go below/around the rudder mount and has two tubes for the platform:

Then I made a platform:

And voila, a removable swim platform:


Now for what I need your help on. I'm afraid to put any weight on it.

I thought that since that 1.5" molding strip (on the first photo above it's where the two bolts go through) that goes around the motor well could hold a ladder and a motor, it should be able to support 500 pounds cantilevered off the back. Then I realized there is reinforcement where the motor and the rudder mounts are located. The ladder was mounted through the strip, and that probably holds up to 250 pounds, but I'm not sure about the extra moment from the platform, let alone somebody large jumping from platform to platform when we are rafted. I have a third hole to the left of the rudder which adds some support but I'm not sure that is enough. I have considered putting a backing plate on the inside of the boat that goes around the rudder reinforcement, but there isn't much room for the holes for the bolts. At best they would be 3/8 of an inch from the edge of the backing plate.

What do you guys think? Is there sufficient reinforcement for just three bolts? Would a backing plate be enough if I can make one that fits?
Help me out here. I think this could be a huge step forward for all of us X owners that have kids who don't like to sail.

[sailboatmike]

The question is, how do you get back in the boat without a ladder, if you go for a swim or fall overboard

[The-strikes]

I either attach a ladder to the platform, compounding the weight problem, use the motor as a step, or I put it on the other side.

[dlandersson]

Your weight will bend the rudder mounts - don't ask me how I know.

Put it (I have a ladder) on one side of the boat.

http://www.amazon.com/4-Step-Telescopin ... RA279J20XJ

[Russ]

Looks very cool. I'll the engineer types answer but I hope it works.

[The-strikes]

Your weight will bend the rudder mounts - don't ask me how I know.

Put it (I have a ladder) on one side of the boat.

http://www.amazon.com/4-Step-Telescopin ... RA279J20XJ

Not sure what you mean. It doesn't touch the rudder mounts. My question was about the molded part of the boat that the rudder mounts to, that you can only see if you crawl into the rear birth and look behind the panel.

[Seapup]

I think it is a solid idea and will work. I have played back there some and with a backing plate there is sufficient strength IMO. People regularly mount kickers on setback mounts off to the side where there is no factory glass reinforcement. If I keep my boat another year I will be extending my deck across the stern to match the 12" setback jackplate I mounted the motor on last year.

In the pic your mount plate looks flat. If it is I would recommend a 1/4" starboard filler to match the hull to the lip so you have a flush surface. Otherwise the plate will only be touching only on the perimeter edges. I would also add bolts to the bottom. Be sure to seal the bolts properly and not to overtighten the bolts on the upper lip or it will crush. On the inside fit backing plates as possible. Since its not a flush surface inside maybe aluminum over a compressible layer to help spread the load out evenly. I think you will find its one of your favorite mods once its all done

[Catigale]

Okay

With three bolts and one square inch of washer behind each you would have at most 170 psi of stress on the FG, in pure tension. This is not a lot of stress for the transom. In reality I think the stress would be less than 1/2 of this as the plate would apply compressive tension to the transom spread over the lower half of its area.

My guess is you could pick up the rear of your boat with three fasteners attached through the lip.

[The-strikes]

Thanks guys. I'll put some weight on it this Friday. Catigale - have to get you back up for another sail some day.

[K9Kampers]

I think that gusset plates should be added to strengthen the weld joints. Then slots would need to be cut in the mounting tubes to accommodate the gussets. That said, trial will tell if it's enough to support weight in use.

[dlandersson]

Sorry 'bout that - looked like the weight was on the steering linkage.

Your weight will bend the rudder mounts - don't ask me how I know.

Put it (I have a ladder) on one side of the boat.

http://www.amazon.com/4-Step-Telescopin ... RA279J20XJ

Not sure what you mean. It doesn't touch the rudder mounts. My question was about the molded part of the boat that the rudder mounts to, that you can only see if you crawl into the rear birth and look behind the panel.

[Catigale]

I would also follow the advice to put a plate in to mount the steel plate flush with the transom, just like the motor mount. See you up at Lake George??

If you can get the washer area up to 2 sq inches that would give you even more margin but the load will probably still be mostly in the first sq inch of washer. FG is surprisingly strong stuff.

[bobbob]

Great idea!

If you added another layer of 1.5" boards perpendicular on top, I wonder if you could extend these boards back over the steering linkage and attach them at a secondary point further back on the boat?

Then you would have a significant cantilevering effect that would distribute the bending moment force between the transom and the deck (in fact, it might all transfer to the deck as the transom really becomes a pivot point and would primary only need to support downward force)

[The-strikes]

I completed the platform this weekend, added a 4-rung ladder, and it works like a charm. Check out the mod. It is so worth the investment.

[bobbob]

I was thinking about using a flip up shower seat for something like this - they seem to be about the right size, are designed for wet environment and look nice. I am hoping there is enough clearance so that when the seat is up the rudder can come up too.