Building a boat ramp, need advice.

[Brahmus]

Getting started on a boat ramp/slip. I'm searching the web and can't find exactly what I'm looking for as far as guidelines and suggestions go. What I really would like to know is the most common Angle of the ramp and depth below waterline to accomidate most boats/trailers. I don't seem me launching any really large boats as the water depth here isn't very deep, but I don't want a ramp too steep or too shallow that my "next" boat won't work. So does anyone have some insight into this realm?

 

[sldva00]

I was thinking about doing the same thing a while back. I came across this site from Virginia fisheries. It may be of some use.

Building Boat Ramps

It has some links for some plans on the top right side.

 

[beenthere]

Of course, it will depend on the depth/weight of the boat and what its displacement is. Contacting a boat sales and service at a marina would be a good guide.

We made a rail system with a "cart" that would pull the boat up the ramp on wheels. Don't recall what the depth was as we had the boat there to go by for measuring. System worked great when we put a winch on it for the older man who owned the boat/cabin. Nice system as then the boat was always high and dry when a storm hit.

 

[Brahmus]

I was thinking about doing the same thing a while back. I came across this site from Virginia fisheries. It may be of some use.

Building Boat Ramps

It has some links for some plans on the top right side.

Funny, that's the only site I had found that was some what useful. Though the grade of 12-15% seemed offly generous.

Of course, it will depend on the depth/weight of the boat and what its displacement is. Contacting a boat sales and service at a marina would be a good guide.

We made a rail system with a "cart" that would pull the boat up the ramp on wheels. Don't recall what the depth was as we had the boat there to go by for measuring. System worked great when we put a winch on it for the older man who owned the boat/cabin. Nice system as then the boat was always high and dry when a storm hit.

Agreed, it's a moving target, but I want to be somewhere in the most versitle range.

 

[firemech]

Brahmus,
we have a marina in the Muskoka area of Ontario Canada with a boat ramp that we launch and retrieve boats up to 25 ft. We use our B7510 and L3400 for this task and for 43 years it has worked well. Our advise is simple, tha ramp needs to be as steep as required to get your boat and trailer in far enough for the boat to float without getting the tow vehicle in too far, but must be an angle that will allow the tow vehicle to be able to pull the loaded trailer back up the ramp safely (our 7510 is maxed out with boats over 18 ft) We made a form from 2X4 lumber and 3/4 plywood that screws together Ours is 9ft wide by 3 ft which we can manuver with our forklift. We pour cement into the form and install two "rings" made from rebar imbedded in the concrete just high enough to put a clevis on a chain onto. When dry we dismantle the form, lift the "pad" into place on the ramp. We start just above the water line and keep advancing with "pads" into the water until we have our ramp built. Ours is long enough that none of our trailers run off the end of the last pad when the boat is ready to push off the trailer. Depth is no issue at our place but we have seen some people make 8 to 10 foot extensions for the trailer tongue with a strap at the far end and a ball back about 3 ft which is attached to the existing tongue so you can get the boat farther in the water without swamping the tow vehicle. The cement doesn't errode and can be installed without causing silt etc in the water/spawning beds. Hope this helps Larry:thumbsup:

 

[Reg]

Well, first you will need to know what you are ALLOWED to do.
If it is a totally private lake that is one thing, if it is or borders a designated wet land that is something else.
If it has seasonal lows you can probably do some work when the level is down, but beware dredging regulations.

Here are a few disjoint numbers and guidelines you can mess with.

I/O "runabouts" up to about 25 ft probably draw 3 ft., maybe 3 1/2 ft when the drive unit is fully down.
I'll go out on a limb here and suggest that 25ft is just about the practical limit for trailering behind a 3/4 ton truck.
It isn't the length, but the proportional depth and width - 8ft 6 in being a highway limit.
Inboard ski boats around 19 or 20 ft draw 2 ft. 18 inches or less when on a plane.
I don't DO the wake fake thang, but I suspect those draw more, since they are pretty much DESIGNED to put up big wakes they almost certainly sit low in the water.

For launching from carpeted bunks a good rule of thumb is to back in until your trailer wheel fenders are JUST under water.
At that point you may be able to float off if the ramp is at a steep enough angle, or you might need to power off if it is a gentle sloped ramp.
I don't have any numbers for this, it is an intuit thing, you go in farther or less when you recover the boat.

This usually turns out that your truck wheels stay dry, which is good.
You might be able to figure a minimum angle from this fact, i.e. truck wheels to trailer wheels when trailer wheels are just covered and truck tires are still dry - tan or sin, one or the other (-:

Sail boats,,,, could be anything, depends largely on whether they have a real keel or a fold up dagger board (-: