[groundhog]

Hi all,

One of the things on my list is a swim platform and a step on the back of my sailboat. This would help in deploying and getting in/out of a dingy, as well as getting people into the boat from the water. Pets might like it too..

Anyway, after I read a recent post about someone getting their outboard engine whacked by a big wave. I have been wondering about the swim platform.

So my question is..
In big water, how would a swim platform do? Would it affect seaworthyness? Get ripped off the back with a big wave?

Thanks,
groundhog

 

[sailingdog]

GH—

It would really help if you said what boat you're thinking of adding a swim platform to... since some boats would look okay with an added platform and others not so good... Also, a swim platform adds a fair bit a weight aft...and that can cause a boat to squat or hobby horse.

The construction of the swim platform and how you're going to secure it to the hull is also something to consider. It has to be attached in a fairly robust way if you don't want it getting ripped off the hull when the boat gets pooped or if the platform gets hit. The worst scenario would be it getting ripped off and tearing big holes in your transom... That would suck... and we'd probably not hear from you again if it happens.

 

[LittleWingCA]

Most swim platforms I see on sailboats near me are integrated into the hull like on late model Island Packets. Are you looking to add one via a fiberglass hull extension, or some kind of bolt on platform? If it is bolt on, then you might want to consider making it a fold up or down for the reasons mentioned above. Maybe some kind of hybrid device that when folded up acts like a teak covered stern life line rail / backrest, but when folded down is a platform.

 

[HARDWORK]

I have a Catalina 30 MK I onto which I have added a swim platform. The stern is solid with no walk thru. The stern rail was cut to make an opening. I build the platform at of 2x2 teak with 2 inch spacing to allow water to flow thru in the event that it was to catch water. I used stainless all-thread to bolt the platform togeather with. On the outside edge is stainless tubing of 1 inch diameter that is thru bolted with the all-thread. To this is attached a swim- ladder that folds up to the stern rail to close the opening. Also from the tubing to the base of the down tubes, or stantions ? , is another 1 inch stanless tube on each side to facilitate hand rails (as well as bracing)
The attachment to the stern is with stainless table brackets that are thru-bolted with backing plates.

 

[sailingdog]

Do you have a photo of your boat and the swim platform???

 

[HARDWORK]

I will try to get a photo posted by tomorrow.

 

[sailingdog]

Hardwork-

Your best bet would be to post in the Song Chain thread about six times, so that you can put the photo up on a Flickr.com or photobucket.com account and then link to it. You can't link to an external photo site until you have TEN POSTS.

 

[FarCry]

In addition to the good suggestions that have already been made...Does anything exit the stern of your boat? Exhaust, bilges etc...that would need to be rerouted.

I saw a very interesting custom swim platform on the stern of a larger boat that had a near vertical stern. The owner installed a couple of padeyes above water line to act as hinges. The actual platform was supported from above via some stainless chain attached to other padeyes high on the stern. When not in use it was raised and tied off to the stern rail. The platform had one of the small two step collapsable ladders on it. The platform was not as pretty as a factory sugar scoop but seemed very funtional and sturdy enough for two people. It looked like it was made out of pieces of teak wide enough for the water to easily flow thru.

 

[sailingdog]

The advantage of what FarCry is describing is that it could be lifted up when in the slip and not count as part of the "length" of the boat when the boat is being measured for slip fees. Remember, a fixed swim platform is going to generally be counted against you when it comes to the marina fees.

 

[groundhog]

Yes, I was thinking along the lines of what HardWork described. Where the slats would drain easily.

My transom is slightly angled forward as you go down to the waterline which is the worst angle to have. That is why I will need a single step between the swim platform and the top edge of the boat transom.

Sailing dog.. thanks for that insight on the length. Didn't think about the extra $$.

I have an Albin Vega 27'. It has 4 cockpit drains and an exhaust port on the back.

I will definitely think along the lines of a hinged unit. But if I was to make it a fixed unit and very sturdy, and wide spaces in the slats, what of a large wave then?

 

[rrh]

Sure would be nice if it folded. Had a big slotted teak swim platform on my power boat. On the hook, seas over a couple of feet would really make it smack. I mean loudly. Other than that, the kids sure loved it and with a ladder it made it really easy to climb back aboard after a swim or snorkel.

Richard

 

[sailingdog]

A cubic foot of salt water weighs about 64 lbs... if the swim platform has a surface area of 20 sq. ft...(2.5' x 8') a wave that is 1' thick and breaks on the platform, you'll have 1280 lbs. dropping on the platform... Something to think about.

 

[xort]

look at some of the Irwins for ideas. they have fold up platforms. Try the irwin 42 for starters. Interesting concept

 

[HARDWORK]

Three points that I need to make , 1. the platform is approximatly 2' by 4', 2 It could easily be hinged to fold up to the stern rail 3. My wife loves the ease of boarding the dinghy. One more point , if Mama aint happy, nobody aint happy !!

 

[groundhog]

Someone mentioned another point.
They said that if you plan to add windvane steering, a swim platform will be in the way. Is this so?

Also, should I not plan my bimini to go too far aft of the transom for this same reason?

thx,
gh

 

[sailingdog]

Yes, most wind vanes need to mount on the transom, if they have a water vane or rudder, so a swim platform can make mounting one more difficult.

 

[cssdengr]

Groundhog-
The PO of my boat built a swim platform that is both lightweight and strong:

Since the picture was taken I've taken the platform apart and given the teak several coats of MAS epoxy and lots of coats of varnish. It looks and works great now, just needs a few coats of varnish yearly. No problems with too much weight at the stern or catching waves.
SF

 

[Faster]

Here's a shot of a Vega transom (sistership)

It looks like a decent candidate for a hinged platform as suggested. In this shot it looks pretty flat but I believe there's a bit of curvature across the stern. This will have to be carefully taken into account when you design the hinging apparatus.

This particular boat has a number of transom fittings (scuppers and exhaust?) that may or may not interfere, do you have the same, GH?

 

[groundhog]

Yes, my boat is exactly like that except I have two more cockpit drains. THe hole on the far right is the exhaust.

The transom does curve a bit in the horizontal and it tilts towards the front of the boat as it goes from top to bottom of the transom.

Seems like every time I try to go in a direction on this boat, I find some other item or system that may interfere with my plans. Everything on a boat seems interlinked to some extent. So you have to have the full plan figured out before you do any modifications.

Oh well.
So I guess now I need to learn about all of the various wind vanes out there before I go on with the bimini or swim platform.
rb

 

[Guidera48]

Hunter 30 platform

I recently inspected a Hunter 30 in Havre de Grace, MD. The owner is an avid carpenter and had many wood upgrades made. One of them was this swim platform. It looked good and was very fuctional. The chains are necesary but look a little home made. A solid tube would double as a handle, however it would not allow the platform to be folded. A divers ladder attached under the platform. Sort of a trailer hitch 2" square pipe receiver for the ladder. It suported a fully equipped diver.