Boat Ramp Design 3

[ChrisL]

Starting new project for local boat club. Interested in Boat Ramp Design. Maximum gradient vs. vehicle traction. Materials and Specifications. Any info would be helpful.

 

[mikolay]

I think the max gradient you want to use is 14% per Wisc DNR guidelines. We use cast in place or precast conc plankes with scored surface.
mikolay

 

[cvg]

we typically use 10% maximum for access ramps to flood control channels, basins, rivers etc. This is typically for maintenance vehicles and equipment.

Chuck
cgopperton@stantec.com

http://www.stantec.com/

 

[snafuman]

We build a lot of boat ramps as I work for a State Park agency. The ideal grade range we like is 10% to 15%. If the ramp is too flat the rear axle of the towing vehicle can end up in the water, which is undesireable (if you have ever spent $1000 to fix a rear end, like me, you understand why). Over 15% and the grade is too steep for many vehicles to pull the boat and trailer out of the water. We build mostly cast-in-place reinfored concrete ramps and improve traction on the ramps by using a "grooving tool" for finishing. The grooving tool is a flat plate with 1" angle iron welded to it at about 3" spacings. When floated across the concrete it leaves 3/4" deep "V" shaped grooves in the concrete. We run the grooves at an angle to the ramp to promote drainage. The grooving is difficult and many contractors bung their first attempt at this. We place a rough broom finish across the grooves for additional traction. We have seen other methods of finishing for traction (stamps, tining machines) but this method is low tech and produces the best results so far. Ramps get slimy with mud and algae and the small impressions made by stamps and tining machines just don't cut the mustard. Don't worry if the concrete finish isn't pretty (it won't be) - the rougher it is, the more traction you get!

Let me know if this is helpful. Leave another post if you need more info.

SNAFUMAN

 

[austim]

Hi, ChrisL,

Boat ramps etc. are entirely outside my personal experience, but you may get some good advice from the Standards Australia website

http://www.standards.com.au.

At no cost, you can download a PDF file of the current Draft Guidelines for the Design of Marinas, DR 00361. (This is the draft revision of a current code of practice)

The grade for boat ramps is recommended to be between 1:7 and 1:9, with 1:8 preferred. All sorts of other requirements are discussed.

You might need to investigate whether the 'typical' towing vehicle used by your club members has too low a ground clearance for 1:8 gradient to work for them. (Every tenth vehicle in Australian cities seems to be a four-wheel drive with high ground clearance, but many other family sedans are to be seen with towbars fitted, many of which would be for use with boat trailers).