MacGregorSailors.com

Mac Bump for me

Start slow and hit the brakes hard. You'll quickly find your optimum speed. Another point is do the bump early when the bunks are still wet.
Taking the time to lowering the mast and other stuff may require a higher speed to bump the boat forward as the buks dry out and friction increases.

Again start at slow speeds but have the guts to go hard on the brake.

Welcome to the forum and being the centre of attention at the boat ramp, especially when performing the bump.
Have always used the bump but have been caught a couple of times, one was after three weeks in salt water and even going down the ramp headfirst wouldn't budge the last foot, the second was three weeks later after a week of fresh water and the slightest bump bent the winch support forward about 2 inches.
With the saltwater episode just kept the winch tight and kept checking it every k or so to tighten it but did have a safety strap as well.
The last few times have sprayed the bunks with sailkote and that certainly helps.
The bump works well but am putting a roller just behind the front bunk to lift the nose and have webbed the frame to stop it bending when retrieving.
Just bite the bullet and progressively raise the speed before braking but don't always assume the next time will be the same if other conditions are different eg salt fresh water and time in water.
Also check your trailer hitch is low enough and you are not pulling your boat uphill, to counteract this I will be making a separate hitch for retrieval which is much lower and getting the fenders at least 3" under water.
When you work out a more pleasant and less attention getting way let us all know.

Another thing that makes the "bump" work better is to loosen the winch cable, strap, or rope. That relieves the tension on the front bunk as the winch pulls the front of the boat down tight. Releasing the pressure allows the front to move forward easier and bring the rest of the boat up on the trailer, where it belongs, with it.

My next mod may be a lower bow cleat so that the winch would pick the bow up, not pull it down.

After replacing the winch bracket, the winch now does pull slightly upwards and straighter which will hopefully stop the bottom plate of the winch bending.
If you leave the winch strap loose be careful to accelerate slowly or the boat will slide back putting enormous pressure on the winch with the boat momentum.

I was having a bit of trouble once or twice last season.

I put soap on the runners just to aid the bump a bit.

Loosened the winch strap.

Hit the brakes.... the boat slid up the big rubber V target about 10 inches lifting the bottom off the bunks by about 5 inches.

Be careful with the bump.

G

I have never had luck with the bump. My truck has anti lock brakes and the lot at my marina is gravel. between theese 2 elements I have never been able to get the sudden stopping jolt needed.

New method I use is to tie the boat to the loading dock once it is on the trailer as far as it will go..next use my tiedown winch straps to pull the trailer up to the hull. this removes the angle problem and centers the boat on the trailer nicely, then tighten the bow and pull out.

I had a very bad gap as the ramp in my marina is almost impossibly steep, but there is no room to have a gentler slope.

Hit the brakes.... the boat slid up the big rubber V target about 10 inches lifting the bottom off the bunks by about 5 inches.

Sorry beene shouldn't laugh but crikey it's embarrasing hey especially when everybody spins their head as the brakes lock up.
With the few modifications and lubricating the bunks don't believe there will be much problem as long as you go nice and steady until you find out the speed it slips at.
Beene did you bend your winch support?

Piece of cake. Just get up to 10-15 mph and hit the brakes... not real hard.

I do it every time and it works great

For those who are having trouble accomplishing the Mac bump, try this approach.

After loading the boat on the trailer, make a U-turn and head for the ramp at 5-10 MPH (8-16 KPH). Three feet before the waters edge, slam the breaks. The down hill effect should move things as well as 6-8 prunes. (please, please, please, don't take this posting seriously)

Ray

I don't do the Mac bump anymore. I now spray silicone lube on the bunks and the winch can do the rest. Make sure you tie down the aft end of the boat good so it doesn't move around on you.

Bump works, I just don't like thinking about all the stuff inside the boat I may not have stowed sliding around.

The first time I did it the boat was crooked because the ramp was lower on the dock side. It would only sit on one side of the front v bunk.

Have someone watch the first time. My next attempt I loaded it and I made sure the trailer was level and the bump worked too well. Had to slide it back a few inches to get it down on the v block. Of course I do have the blue hull

I have a friend with a ski boat that has to do the same thing. May be that our ramp is steep. His wife does it no problem.

Wally

I worry a little about the vertical post that the boat nose pushes on getting stressed or even collapsing on an overly aggressive "mac bump." When I was in Canada at LOWISA last year, a travelling companion with a Tanzer 27 had to brake for a deer. The surge brakes worked well; the forward post collapsed and the boat slid forward into his topper.

I bought my 06 last fall and it already had bottom paint on it so it does not slide that easy. The first time I tried the Mac bump the boat slid a little sideways and took a little chunk out of the bow so I recently replaced the little roller with double the width and bigger diameter roller to keep the damage from happening again, it covers the metal roller supports totally. I had to drill bigger mounting holes . I am also thinking of replacing the carpet covered bunks on the trailor with a poly plastic 1/2 inch thick. I think this will cause me to strap the boat to the trailor down better to keep it from sliding when I dont want it to, but I will try adding soap first.

Well I wouldn't say it is that easy, I have done it successfully most times (never @10-15mph) but on one occasion I hit the brakes too hard and the boat lurched forward enough to bend the ladder and post forward. I used a come-along attached to the axle to straighten it best I could but you can still see the evidence of my heavy brake foot. Take it slow and careful.

Start slow and find the speed. Its kind of an all or nothing, the boat moves or it doesnt. You want to find the speed that the boat just moves as it is a small gap. Start slow and increase the speed as needed.
All it takes is courage to hit the brake. HARD