Advice for mounting swim platform

[eztbone]

I'm looking for some advice on mounting the teak swim platform to the transom. I'm having stainless brackets built with backing plates. I have good access in the hull for the inboard brackets but the outboard brackets are tough to reach. The fuel tanks are backed up pretty close to the transom and close to the deck making cutting access ports difficult also fuel and water hoses running right over best place to cut. Any help is appreciated. Also this is a cored hull but I should be able to remove coring and thicken some west from outside. Thanks

 

[eztbone]

Pics

I'm having trouble submitting multi pics from I pad. Seems I need more help then just mounting platform

 

[eztbone]

Inside shot

From center hatch

 

[eztbone]

Similar bracket

This is a similar bracket I'm having fabricated

 

[RyanCT]

nut captivator

You can have nut captivator welded to the backing plate. That way you won't need to get a wrench in there. That could save some time and cursing during install.

Can you reach in there to get the backing plate into position?

 

[captchuck]

I used Lag Screws for the locations that I could not reach when mounting my platform. So far so good

 

[eztbone]

Platform

I was thinking of having the bolts welded into the backing plate and between snaking some monofilament and using a Dowel to guide the bolts into the holes

 

[RyanCT]

I was thinking of having the bolts welded into the backing plate and between snaking some monofilament and using a Dowel to guide the bolts into the holes

That seems like it could work. You could weld the nuts on instead, in case you only want the head of the bolts outside. Then use threaded rod in two of them to get lined up an into the holes (easier to line up to 2 then all 6 -8). Then you can use bolts in the empty holes from the outside, back out the threaded rods and insert the last 2 bolts.

I mentioned the captivator nut (also called a cage nut) as they give you some tolerance in all directions including the bolt not going straight in. Basically it is a cage around the nut that allows the nut to float but not rotate. Maybe not necessary as long at the holes thru the hull allow some clearance.....and they may be hard to find in stainless.

 

[chortle]

Can you hinge it in the corners and hang it from above with cable or chain or pipe? I have seen that more than once, allows you to swing it up when you dock or makes the boat shorter for those yards that haul by the foot and include swim platforms and bowsprits.

 

[Lion's Paw]

I have put platforms on four of my boats and all had some access issues with the mounting systems.

One thing to consider is that you are only going to mount this one time and going thru a bit of a struggle to get a backing plate on and bolted down is just the one time event. Over thinking it and engineering some ease of installation hardware might just be more trouble than finding a skinny and flexible guy to get the hardware on and hold onto the wrench.

On my henriques there were some issues with access and the answer was to install some SS threaded inserts (mcmaster carr) directly into the glass of the transom from outside. Just drilled and taped the glass for the inserts. Easily attach the brackets with 3/8 bolts and the platform stood up to great abuse without issue for years. This may not work as well with cored hull but did great on the overbuilt henriques hull.

On the Hatteras the outboard brackets tuff to reach so did them with long reach pliers and some squeezing into place. The current Duffy was just some squeezing in and being uncomfortable but at first look seemed not possible.

Individual backing plates for each bolt can be easier than a single big plate and really just as strong for the application. I have done it both ways and the big plates needs larger holes so the bolts dont all have to line up exactly perfect. You do need to take care of the core issue but that is easy and sounds like you already know what to do. Bonding wires are easy to do if you plan ahead and have them made up already when bolting it all on.

 

[Toolate]

Not the answer your question with a question (but I am going to ) but have you considered making that removable section of your transom into a tailgate instead? Think you are a hinge and some cables away from a cool platform.

 

[eztbone]

Do you plan on connecting the brackets to the bonding system? and have you contemplated how?

Good point. A tab welded to the backing plate would do it. Thank you

 

[eztbone]

Not the answer your question with a question (but I am going to ) but have you considered making that removable section of your transom into a tailgate instead? Think you are a hinge and some cables away from a cool platform.

I thought about that. It would be a project. There is a post where they are doing that at sw I think

 

[eztbone]

I have put platforms on four of my boats and all had some access issues with the mounting systems.

One thing to consider is that you are only going to mount this one time and going thru a bit of a struggle to get a backing plate on and bolted down is just the one time event. Over thinking it and engineering some ease of installation hardware might just be more trouble than finding a skinny and flexible guy to get the hardware on and hold onto the wrench.

On my henriques there were some issues with access and the answer was to install some SS threaded inserts (mcmaster carr) directly into the glass of the transom from outside. Just drilled and taped the glass for the inserts. Easily attach the brackets with 3/8 bolts and the platform stood up to great abuse without issue for years. This may not work as well with cored hull but did great on the overbuilt henriques hull.

On the Hatteras the outboard brackets tuff to reach so did them with long reach pliers and some squeezing into place. The current Duffy was just some squeezing in and being uncomfortable but at first look seemed not possible.

Individual backing plates for each bolt can be easier than a single big plate and really just as strong for the application. I have done it both ways and the big plates needs larger holes so the bolts dont all have to line up exactly perfect. You do need to take care of the core issue but that is easy and sounds like you already know what to do. Bonding wires are easy to do if you plan ahead and have them made up already when bolting it all on.

Some great ideas suggestions and experience on this site. I think it's doable without cutting the deck. Appreciate it. I'll keep you guys posted as it comes together

 

[South Shore Boatworks]

folding transom/ swim platdorm

The boat that we are currently building has a hydraulically operated transom/ tailgate that hinges down to become a swim platform. we used hydraulic cylinders- not cables. It was complicated to design and build but works great and eliminates the need for a separate swim platform

 

[riskybusiness]

plexus.....fabricate fiberglass brackets and glue em on....they will never come off...

 

[nickyp]

Have installed a number of platforms with brackets like you want.
Decore and fill with thickened epoxy.
Bolt and back up what you can, drill and tap the rest. Dip the bolt threads in epoxy before sending them home.
If you need to remove the brackets in the future, some heat on the bolts will break down the epoxy bond.

Fiberglass brackets sound great

 

[Toolate]

plexus.....fabricate fiberglass brackets and glue em on....they will never come off...

How wide would you make the bases of something like this to be able to support the platform and say 4 people though? I imagine it breaking off when the bride and groom are taking the getaway pics at the yacht club.

 

[Chum Pot]

outside of the platform mount, ensure the platform it's self has structure.
if making one out of fiberglass add some structural ridges or cross members to the bottom so it is not all wobbly and flexy

 

[eztbone]

Platform

plexus.....fabricate fiberglass brackets and glue em on....they will never come off...

You may be on to something there.