Swim step considerations

Sea Word · May 31, 2019

Maybe it’s a dinghy platform,or swim step, hull extender, or just generally a good idea. I dunno what it’s called but I WANT ONE. So we have been tinkering on an aluminum hull and it has no swim step at all. This makes boarding from dinghy a challenge, and I love having access to the water. So, I’m going to make a generous platform and weld it permanently on. But, I had a thought that if it’s too close to the water, that wakes and such will slap it and make noise/ make me insane. SO what height would you want your swim step?
This is a river boat and we anchor where there are some pretty nasty wakes, we get freighters and big yachts and barges that can toss a pretty good wake our way. But generally the kind of waves that smaller yachts throw are what we worry about most.

menzies · May 31, 2019

Sea Word said:
Maybe it’s a dinghy platform,or swim step, hull extender, or just generally a good idea. I dunno what it’s called but I WANT ONE. So we have been tinkering on an aluminum hull and it has no swim step at all. This makes boarding from dinghy a challenge, and I love having access to the water. So, I’m going to make a generous platform and weld it permanently on. But, I had a thought that if it’s too close to the water, that wakes and such will slap it and make noise/ make me insane. SO what height would you want your swim step?
This is a river boat and we anchor where there are some pretty nasty wakes, we get freighters and big yachts and barges that can toss a pretty good wake our way. But generally the kind of waves that smaller yachts throw are what we worry about most.

If the wakes concern you that much consider manufacturing a swim platform with slots - have a look at the Kady Krogen swim platform for ideas. Also consider size. It doesn't have to be large if you are using it for swimming rather than dinghy storage - again look at the KKs.

http://s3.amazonaws.com/bluewaterboss/ForSale/Vessel/Photo/1219443/large_264486.jpg?w=862&h=575

https://encrypted-tbn0.gstatic.com/...YOKKqp34ZIrWx5ofOER8JVRJ_TPuJn1hsHfbMvmoPAE6L

https://docplayer.net/docs-images/65/52632621/images/23-5.jpg

O C Diver · May 31, 2019

You might consider one that is hinged. Fold up out of the way when you don't need it and less engineering for shock loads. While I'm sure your boat has a strong transom, but large swim platforms can have tremendous loading from a stern wave or wave coming up from underneath.

Ted

Alaskan Sea-Duction · May 31, 2019

I believe GFC had a swim deck made. He could chime in here or PM him.

Sea Word · May 31, 2019

I’m not sure the transom is super strong actually. Might only be 1/8”. It’s a pretty light built boat for its size.
I want a full width platform. Bigger is better. I like to have close access to water, and both sides.
Slots or holes, not ideal, but could be a good solution to mitigate a big slap.
I did consider a hinge too, but I’d rather have it solid for the obvious reasons, rigidity, ease of mfg, solidity, aesthetic.

healhustler · May 31, 2019

When you say you have a river-boat (meaning a flat river-boat style hull and a flat stern), your boat may not lift particularly well when stern-to the wakes. If that's the case, I wouldn’t do anything less than a foot off the water and as noted above, plenty of reliefs cut into the platform to disperse energy. Don’t be tempted to just weld on solid plate gussets for support as they will trap wave energy and slap even worse. Make your gussets with flatbar or tubing triangles so wave energy can escape to the sides.

caltexflanc · May 31, 2019

These are the guys to talk to. Extremely knowledgeable.

https://butlermarine.com/

Comodave · May 31, 2019

How about a photo of the transom?

LaBomba · May 31, 2019

We had a folding swim platform on our last boat as Ted described and it worked very well. It was only about 4 inches off the water when down but we always traveled with it in the raised position and only lowered it when using the dink or wanting to sit and dangle the feet. Our current boat has a solid platform, about 8 inches off the water and every now and again when a wave hits the right (or wrong) way we can get a very loud bang. It generally doesn't happen as anchoring into the wind, the waves are usually from the bow and nothing gets under the swim platform.

Sea Word · May 31, 2019

Here’s what we up against.

menzies · May 31, 2019

Hmmm, outdrives.

That kinda changes the conversation a bit.

rsn48 · May 31, 2019

Here is my boat with a stern drive, but single engine. Obviously the platform has to go above the leg cut outs. My swim platform is being widened and raised a bit so it can be used to enter the boat from the transom area.

Second picture in:

https://www.facebook.com/marketplace/item/222498835044761/

O C Diver · May 31, 2019

Were you planning to have the platform above the outdrives and extend past them to the sides? Think a fixed platform is going to make it that much tougher to work on the outdrives or remove them when you're in the boatyard.

Ted

Paul in Saudi · May 31, 2019

O C Diver said:
You might consider one that is hinged.

Ted

I agree completely. To me, the ability to lift myself from the water to the boat is simply a safety issue. I am not able to climb a line to the deck, but a swimming step makes an embarrassment out of what might otherwise be a major accident.

So I think a well-founded boat needs one. After that, there is no obvious disadvantage to a folding one.

GFC · May 31, 2019

I had a fiberglass one built 10 years ago by Multnomah Yacht Repair which is right in PDX. They did a great job but it was too long (fore to aft) and ended up getting hung up in some of the big waves we have up on this end of the river. It broke and we had to replace it this year.

I had another built but it is in fiberglass and the guy that did it I believe only works on glass boats.

Sorry I can't be more help than that.

Sea Word · May 31, 2019

menzies said:
Hmmm, outdrives.

That kinda changes the conversation a bit.

Yes sorry I should have mentioned that. Another reason for swim step is to hide these hideous things.

Sea Word · May 31, 2019

O C Diver said:
Were you planning to have the platform above the outdrives and extend past them to the sides? Think a fixed platform is going to make it that much tougher to work on the outdrives or remove them when you're in the boatyard.

Ted

Why would it make harder in the yard to service? My plan was to have removable plates above each one for service or messing around. Now that I look at the picture there isn’t as much choice for placement as I thought, above the drives and below those exhaust ports is the place we will end up. Maybe the structure could be welded rigid tube, and the hatches could be hinged. Would still slam like hell if hit by a wave, but wouldn’t rip it off the boat at least lol.

Comodave · May 31, 2019

Now that we can see the transom, it will either have to be high enough for the outdrives to tilt up and still be below the bottom of the platform or you will have to have 2 hinged sections right above the outdrives so you can tilt the drives up and the hinged sections tilt up also. I have seen platforms that have tilt up sections for the outdrive, just a bit more complexity. As to restricting the access to the outdrives, it isn’t a real problem. Lots of outdrve boats have platforms. I have owned 5 or 6 myself and never had any access issues, just have a rolling seat so you can roll under the platform and sit to work on the outdrive.

Sea Word · Jun 1, 2019

Yes the hatches over the drives will be large for good access. Hmm, maybe if the have gas springs on them they would act like shock absorbers lol. I can use perforated metal to allow some grip and reduce the water wall area.

Comodave · Jun 1, 2019

The ones I have seen with tilt sections had a strip on the tilt section that would allow the outdrive to slide as it tilted up. Maybe a strip of UHMW plastic?

Sea Word · Jun 1, 2019

Yep, I can see that.

Swim step considerations

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