Making a home made boat ramp? Need to sink a 4x4 post...

[nola mike]

I'm trying to build a rig that will pull my Carolina Skiff J14 with 25 hp merc out of the water, up my small beach, over my ~3-4' retaining wall, and onto the lawn. The ramps need to be removable. I have a couple of 16' 2x8's braced together that are supported at the retaining wall. So the plan is to sink a 4 x 4 in the lawn, and place a winch on that. I'm not sure what it is, but I hit something plastic about 30" deep and can't go deeper. I don't know if this will be deep enough to secure the post; I was going to put it in 12" diameter concrete. What would be the best way to reinforce that post? I was thinking about maybe another 4x4 mounted at a 45' angle, or some sort of wide metal bracket/plate at the base, or nothing? Obviously the stress on the post is going to depend heavily on how high I mount the winch--I think I can get away with 3'.

 

[smokeonthewater]

Did you get a one call done before sinking that pole? You could have hit anything from a water line to a buried pipeline to a fiber optic cable. .... Better yet it checked out ASAP

 

[nola mike]

No, this is right near the water line. No utilities anywhere near there. Only thing I can think of is maybe part of the septic drain field, but it's still way too far away for that. Hell, it may not even be plastic, just sounded like that when I tapped the post down, and didn't want to try to dig through it...maybe I can take a closer look, but am trying unsuccessfully to keep this from becoming a big project.

 

[Mi duckdown]

Pics are always Good. Not a mind reader

 

[nola mike]

Pics of what? Post isn't in the ground yet.

 

[midcarolina]

I am sure someone here is a math wiz and could tell you what kind of stress would be on the post........but it aint me..:joyous:

If I where building something like this I think I would ditch the 4x4 and use 4x4 or 4x6 heavy walled steel box tubing...Then over engineer it from there!

 

[nola mike]

Well, I'm not really worried about the strength of the post. It's more the strength of the ground; I'm afraid that without burying it deep it will pull out of the ground.

 

[Mi duckdown]

Good bye

 

[nola mike]

Bye bye.

 

[Gyrene]

I have just the thing for you. An alloy wheel w/tire. Rim is cracked, but that's not important. Bury the wheel/tire vertically up from your post and run a cable thru the hub of the wheel to your post. Won't pull that out...

(I hit a rock and had to buy a new rim & tire - I'll let you have it real cheap)

 

[hockynut2]

I am no engineering expert, but usually the ground near the water edge will be very soft and even good chance the whole concreted slab could pull loose if there is enough pull. My suggestion would be to concrete and bury 2 separate posts in a row and make your winch onto a piece that will connect the 2 together making it a much stronger union to support your boat

 

[midcarolina]

do a google search for concrete deadman anchor......or deadman anchor. the idea is with enough concrete for weight the thing is stable and the post is there for attachments.....

 

[coolbri70]

http://washingtondc.craigslist.org/nva/boa/4527486059.html

 

[nola mike]

Thanks for the tips.
@coolbri: that shore dock is AWESOME. Unfortunately, it wouldn't work to get it on top of a sea wall without some significant modification

Looked up the deadman, etc. In the end, decided I was overthinking things (the boat is only ~600#). Dug a 32" deep hole extending 18" in the front, and sunk it in concrete. That thing is definitely not moving. I do wish I had gone with a thicker post though. There is a little flex in the 4x4, so we'll see how it holds up. I'm going to mount the winch lower down on the post to reduce the force on it. The rest of the ramp worked fine, 3 people were able to drag the boat up (before I installed the winch) over the raw wood. I have some trailer slides on order that I think will help a lot. I'll post some pics next week when I get back there and finish up.

 

[staydry]

That plastic "thing" you hit was probably part of the tie-back system for your sea wall......

 

[nola mike]

Yeah, I was wondering about if it was the tie back. When I dug it out further though, it was some clay/brick chunks, so who knows. Managed to sink it though, and all was working well. The winch bunched up on one side and bound up when I was paying attention to the boat instead of the winch. Got to figure out how to prevent that from happening again. Let's see if I can post pics yet...

Eh, guess not. I'll try again later.

 

[nola mike]

No Title

Let's see if this works...