Ladder Mount Question

[Ward H]

My O'day never had a stern ladder. I've been planning on installing one since I bought the boat. The ladder will be for emergency use only.
I found one with enough steps, 5, that I can mount it so it has a couple of steps in the water when lowered to make it easier to climb aboard.
My question is how to mount the brackets pictured? Four 1/4-20 (or 24) machine screws just don't seem to be that strong. The brackets seem to also accommodate some kind of single larger mounting bolt of some type. The machine screws pictured may be just for assembly and not for mounting the brackets to the transom.
My plan is to use a single piece of teak as an outside backing plate on the transom and epoxy in a 3/4 epoxy saturated plywood backing plate on the inside with fender washers under the machine screw nuts. I'll use thickened epoxy between the inside of the transom and backing plate to fill any gaps.
Would shoulder bolts offer more shear strength than threaded machine screws or will the screws be enough?

 

[Ken Cross]

In shear one of those 1/4 inch bolts should easily hold you. You said there were 4 of them.
If you are still nervous do a test on a single bolt and size it down one size (to a #10 using washers). hang your ladder to anything other than your boat and put your weight on it. Then remove the bolt and look carefully for deformity.
Ken

 

[sailnoproblem]

The Shear strength of 1/4-20 bolts is more than you will need. I would use starboard as the backing plate. I'm not a big fan of using plywood for backing plates. If the bracket holes are large enough go with 5/16-18 or 3/8-16.

 

[pipedream]

You will be just as satisfied with G10, or other sheet frp for backing. Cost is about the same, even less if you can find a section of frp out of a derelict. Wide and inside the boat is good. no swelling teak outside to loosen in dry months. If you cant find G10, look for scrap Stainless plate.

 

[Dalliance]

The bolts are more than adequate. The epoxy saturated plywood backing plates on the inside are enough if adequately sized, but fiberglass or stainless steel would be a better choice because they won't rot or crush.

What is the purpose of the teak "backing" plate on the outside? Is it purely decorative or acting as a spacer for more toe room? It will be an additional maintenance item, increases the required bolt length and may actually work against you structurally.

 

[Brian S]

I don't care for Starboard as a backing plate, because it will creep under load. If you use G10 or derelict fiberglass laminate, cut a bevelled edge all the way around to reduce stress risers at the edges of the backing plates.

On the other hand, there won't be all that much consistent load on a Starboard backing plate for THIS application, so it would do ok if you had it on hand.

 

[Ward H]

Thanks for the suggestions and confirmation that the 1/4" size bolts will be fine.
My OB has what looks like starboard for outside and inside backing plates for the bracket mount. After 10 years no problem there. (Original owner had it installed.)
I have a scrap piece of 3/4 starboard that should work fine for this application. If I can't find it I will pick up some G10.
On the outside I just thought the teak would provide a bit of cushion to spread the load of the brackets. Yeah, that's probably not needed also.

 

[Ward H]

Just to follow up, I followed the suggestion to use G10 as backing plate material. I bought some 1/4" x 12" x 12" G10. I used a full 12" x 12" piece for the bracket mount area and a 6" x 12" piece to strengthen the area where the ladder supports rest. I used epoxy thickened with chopped fiberglass to set the backing plates. I also used 1/8" x 1" x 6" SS flat bar as additional backing for the 1/4-20 bolts.
The ladder is a bit narrow but I chose it for its length. It has a clip to hold it folded up so I will put a short line on it so it can be pulled down from the water.
Here are some pics and here is a little brag. When I replaced the rudder mounts 3 springs ago I had to have someone go under the cockpit to remove and to tighten the nuts for me because I didn't fit. Since then I lost 45 lbs and now can move around in there and do this work myself.

 

[agprice22]

Smart work! And congrats on losing the weight. Good job!

 

[sailnoproblem]

Just to follow up, I followed the suggestion to use G10 as backing plate material. I bought some 1/4" x 12" x 12" G10. I used a full 12" x 12" piece for the bracket mount area and a 6" x 12" piece to strengthen the area where the ladder supports rest. I used epoxy thickened with chopped fiberglass to set the backing plates. I also used 1/8" x 1" x 6" SS flat bar as additional backing for the 1/4-20 bolts.
The ladder is a bit narrow but I chose it for its length. It has a clip to hold it folded up so I will put a short line on it so it can be pulled down from the water.
Here are some pics and here is a little brag. When I replaced the rudder mounts 3 springs ago I had to have someone go under the cockpit to remove and to tighten the nuts for me because I didn't fit. Since then I lost 45 lbs and now can move around in there and do this work myself.

 

[sailnoproblem]

Nice job, that ladder is going nowhere.

 

[oldlaxer1]

Just to follow up, I followed the suggestion to use G10 as backing plate material. I bought some 1/4" x 12" x 12" G10. I used a full 12" x 12" piece for the bracket mount area and a 6" x 12" piece to strengthen the area where the ladder supports rest. I used epoxy thickened with chopped fiberglass to set the backing plates. I also used 1/8" x 1" x 6" SS flat bar as additional backing for the 1/4-20 bolts.
The ladder is a bit narrow but I chose it for its length. It has a clip to hold it folded up so I will put a short line on it so it can be pulled down from the water.
Here are some pics and here is a little brag. When I replaced the rudder mounts 3 springs ago I had to have someone go under the cockpit to remove and to tighten the nuts for me because I didn't fit. Since then I lost 45 lbs and now can move around in there and do this work myself.

Congrats on the weight loss.
Where did you get the ladder? I'm looking for one similar to that. Thanks

 

[Scott T-Bird]

Since then I lost 45 lbs and now can move around in there and do this work myself.

That's fantastic, Ward! Do you want to crawl in my lazerette and help me install my water heater? It should be hot and humid by the time I'm ready, so you can lose more weight!
I like that ladder mount. Who made your ladder? I also want to have one made.

 

[agprice22]

The thing I have never liked about the ladders is the feet that rest against the transom. They wear out quickly. I have thought about mounting a small block of starboard on each foot to fend them off the hull.

 

[Ken Cross]

Nice work. It always amazes me how many boats have no ladder. This pretty much guarantees you can't get back in if you go in the drink (even at anchor.) I like better odds than that. One exception; outboard powered boats. with the motor off I have climbed up the motor an many occasions.
Ken

 

[pipedream]

Well done. Nice to have your project complete with no follow up required.

 

[jssailem]

I have climbed up the motor an many occasions.

How long ago was that?

 

[Brian S]

Haha, I used to climb up the '63 Johnson 90hp on my Grandfather's wood lapstrake 19' Cruisers by Thompson runabout. Given my fear of propellers, it was like a personal dare to me to put my feet near the propeller of a motor that wasn't even turned on. I think I tried to climb up the 120 Merc on my buddy's boat after I kinda got run over by the boat (no propeller involvement THANK GOD) but they told me they lifted me into the boat. And that was 25 years ago. Ain't nobody climbing up my 6hp kicker on an aluminum lifting mount nowadays

Funny story about propellers, I worked with a guy who had a bunch of scars on his face, mostly hid by a beard. I finally got him to tell me what they were from, that he was cut by a capsized small boat as a kid. 2nd co-worker was like "Dude, you totally knew that!" and I was like "No, I didn't." And they were like, "Yeah, he told you that before." So I guess even to this day I have such a fear of propellers (based on my Grandfather's admonition, I suppose) that I mentally blocked out the co-worker's story the first time he told me.

 

[Ken Cross]

How long ago was that?

It had to be in 1995 the last time. And I never said it's ideal. It's actually easier than you might think to climb an outboard. That assumes it's big enough that you can get a foot on the cavitation plate. it might be tougher on some of today's giant modern outboards as there may not be anything to hang on to with all those curved surfaces.
Ken

 

[Ward H]

Nice to have your project complete with no follow up required.

Yes it is.

The ladder came from Amazon and is made by Forester. Sold by NS Marine & Leisure. Cost $109. They are shown as out of stock now.

Scott, say when. BTW, you boat was hanging on the travel lift last night when I stopped by. Looked like it needed bottom paint where the cradle pads were, then was going in.