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Add on swim platform
Posted: August 15th, 2018, 11:15 am
by Guy
Reposting in case the earlier post didnt make it.
Hello all, guy here. 1989 santego 3467. Need to add to swimplatform as I will be buying the hurley marine h3o davit system and the platform needs to be 40 inches from transom. Have a buddy to build the platform 10' 4"x40 deep.
Looing for info from anyone who has done a similar project. My project is to lay this new flat platform on the existing one that is 18 inched deep thus only having 22 inches over the water supported by stainless stanchions from transom to underside of new platform.
In the category of I dont know what I dont know, any hazards I'm not thinking of. How is best way to secure the new to the old.
Thanks all
Guy
Re: Add on swim platform
Posted: August 15th, 2018, 8:03 pm
by km1125
Do a search on here. One of the guys with a 3207 built his own larger platform. He replaced the original, so it won't be an apples-to-apples comparison, but he has to put extra braces out farther to support the expected load (dingy, steps, etc)
EDIT: Here's the thread:
viewtopic.php?f=13&t=27
Re: Add on swim platform
Posted: August 15th, 2018, 8:30 pm
by Guy
Thank you sir. Wow that was quite the peoject
Awesome work, hoping mine looks that good
Guy
Re: Add on swim platform
Posted: August 16th, 2018, 7:11 am
by Viper
I would only fasten an extended platform to an existing one if the existing one is structurally sound and there are NO areas of concern in the core. All fasteners currently on the existing platform should be removed and rebedded prior to installing the new unit on top. Unless there will be a large gap to allow for air circulation, you should also try your best to seal the area between the two platforms to prevent water from accumulating there for long periods of time as this could have long term consequences. If it's going to support weight while underway such as a dinghy, the more support the better. Your goal is to eliminate movement and flex. While there won't be much at rest, there will be a tremendous amount of stress while underway, especially in rough seas. Ensure that the supports are thru-bolted through the transom and not just screwed to it.
I trust you've confirmed that the additional depth of the platform will not interfere or dig into the water when getting up on plane. Depending on the design of the new platform, the geometry of your particular application, and how high the trailing edge of the new platform will ride above the waterline, you need to consider whether vents are required.
Pics would be great

PS; maybe one of the moderators can move this thread into a more appropriate area that might get more attention.
Re: Add on swim platform
Posted: August 16th, 2018, 8:19 am
by Guy
Awesome response viper, thanks.
Yes I worried thos post was in the wrong place.
As you know the santego platform is quite substantial as it is a molded platform and three steps on both sides. All appear in good shape. God thought on sealing both.
Be well
Re: Add on swim platform
Posted: August 16th, 2018, 8:35 am
by Midnightsun
I did this project on my previous express cruiser added 21" to the mid section to be exact. I simply unscrewed it, cut it down the center from port to stern and had a professional install the 21" section. I did it this way because I could utilise the existing way it was attached, the ladder and the rounded rear shape remained intact. Pretty simple to add a rectangle to the middle. The bottom was reinforced with 3 stringers for lack of a better word and I added 3 braces that extended further out than the originals which looked kinda short after the extension was on. The guy charged me "cough cough" $700 "cough cough".
Bottom line is this method is definately the easiest route to go IMHO.
Here you can see the center section is added, only missing step was to finish the top with anti skid.

This guy worked magic with gelcoat, see the fantastic finish/workmanship on this.

Re: Add on swim platform
Posted: August 18th, 2018, 8:37 pm
by Guy
Such a great job. Heres hoping mine comes out the same.
Did you experience any planning issues with the added depth??
Thanks very much for writing back
Guy