A liitle Feedback with respect to the MAC Bump

[wlcenterville]

I can explain the Mac bump problems. For 8 years, I did the Mac bump with no problem. I had gel coat - no bottom paint. This year, I put barrier coat and Hydorcoat ablative bottom paint on. The boat and trailer will NO LONGER do the Mac bump! I had all wheels locked up and the boat would not slide on the trailer. I put on a bunk slide product called "Liquid Rollers." It now slides a bit but it is too difficult to do safely. I prefer some other solution than the Mac bump.

The reason there is a gap is because, on loading, the angle of the trailer and the angle of the boat are different. The winch and rubber V block are on a lever arm and a trailer in deep water levers the rubber "V" block farther out. The deeper the ramp, the greater the diference in the angles, the more the rubber V is levered out, and the more the gap will be. That's why cranking as you pull out helps reduce the gap. As you pull out, the angle of the boat and the tailer become the same.

I think the big problem with the trailer (I have a 26x) is the front V bunk. If that were rollers somehow, or something more slippery, you could more easily crank it up as you pull out. I reach a limit where I can't crank it up any further and a gap remains. That may be a problem with the winch position.

A solution might be the suggestions mentioned in this thread. Replace the rubber V with a roller and change the winch position.

[Pete]

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My old V22 has the same problem.

I recall a discussion about the winch not being strong enough with a picture of the winch being pulled away from the mount on the trailer. I believe the problem there is that if you winch the boat up tight and then pull up the ramp, the boat is pivoting on that front bunk, and putting tremendous force on the winch. This force could easily be much more then the entire weight of the boat. The boat being a lever and the front bunk being the fulcrum. You know that saying "Give me and long enough lever and I can move..." Looks like you have a 26' lever with a 300 pound weight on the end. I would guess that if everything was ridged you would pull the boat out and find the back end of the boat off its bunk. But there is enough flex and give in the trailer and winch strap to allow the back of the boat to land on the bunks.

[pokerrick1]

I can explain the Mac bump problems. For 8 years, I did the Mac bump with no problem. I had gel coat - no bottom paint. This year, I put barrier coat and Hydorcoat ablative bottom paint on. The boat and trailer will NO LONGER do the Mac bump! I had all wheels locked up and the boat would not slide on the trailer. I put on a bunk slide product called "Liquid Rollers." It now slides a bit but it is too difficult to do safely. I prefer some other solution than the Mac bump.

The reason there is a gap is because, on loading, the angle of the trailer and the angle of the boat are different. The winch and rubber V block are on a lever arm and a trailer in deep water levers the rubber "V" block farther out. The deeper the ramp, the greater the diference in the angles, the more the rubber V is levered out, and the more the gap will be. That's why cranking as you pull out helps reduce the gap. As you pull out, the angle of the boat and the tailer become the same.

I think the big problem with the trailer (I have a 26x) is the front V bunk. If that were rollers somehow, or something more slippery, you could more easily crank it up as you pull out. I reach a limit where I can't crank it up any further and a gap remains. That may be a problem with the winch position.

A solution might be the suggestions mentioned in this thread. Replace the rubber V with a roller and change the winch position.

Where you been all our lives? This is your first post??? It is MOST INTELLIGENT!! Please post more often!

I was of the opinion that those guys who were having problems executing the MacBump were wimps who just were not going fast enough or hitting the brake hard enough and that if I were doing it on their boat there would be no problem - - - well now here comes a guy who did it on his for eight years and then could no longer execute it! Evidence of that nature certainly caused me to pause and think that there can be more to the MacBump than lack of skill.

Great Post

Rick less in Las Vegas

[C Striker]

I do the Bump and hate it. Next time I will take my dear sweet time and hop in and out of the truck winching as it settles.
I like the rubber V block when its doing 70 knots on the highway. That is a keeper for me.

I did the bump once and forgot about the dog inside. Not that putting her in the truck is that much better. And what of my gear inside, or the staples on the bunks, or the wear and tear on everything.

I know its in the manual but so is running a wire from a shroud to ground the mast. Thats not happening here either. I ground data centers at work and don't feel like turning my mast into a lightning rod.

Erik

[Retcoastie]

I believe the problem there is that if you winch the boat up tight and then pull up the ramp, the boat is pivoting on that front bunk, and putting tremendous force on the winch. This force could easily be much more then the entire weight of the boat.

That is because the winch is below the bow eye. As the boat settles, the bow eye pulls up on the wench. If the wench were above the bow eye, the boat settling would not put additional stress on the wench or the mount.

I put a roller just forward of the front vee bunk. When loading the boat rides on the roller until I'm almost out of the water and then it settles onto the bunk. This does not help with the gap and still requires a "bump".

[Wind Chime]

If the wench were above the bow eye, the boat settling would not put additional stress on the wench or the mount.

... do I need to say anything ???

[SkiDeep2001]

Yes, I need to find me a 'wench' to assist in loading my Rob - on edit - Or maybe 2 wenches would be better.

[Retcoastie]

Now that you point it out, I have a wench for loading, but she is about as helpful/useless as the winch.

[pokerrick1]

Training, Training, Training. Discipline, Discipline, Discipline

Rick less in Las Vegas (but still having a blast)

[SkiDeep2001]

Training, Training, Training. Discipline, Discipline, Discipline

Rick, I assume you are referring to the wenches Rob

[pokerrick1]

Training, Training, Training. Discipline, Discipline, Discipline

Rick, I assume you are referring to the wenches Rob

Of Course

Rick less in Las Vegas - but there are LOTS of wenches here

[trip01]

Newell,

Solution for me: Removed the winch turned it over and mounted it on backside of original location. Drilled a hole and led rope (cable or strap) through to hook. Now winch is pulling up not down on the boat. Has worked for 10 years no mac-bump bs. Cost, I think I bought a drill bit.

I reckon you have the solution. Makes sense, & after reading other replies, easy to relate to.

I would like to see a photo of your mod. Mine's a strap winch, perhaps after seeing yours I could rig something similar accounting for the strap.

Kind Rgds
Dave
Mac 26M/alloy trailer - Landcruiser HDFT

[uncle trev]

hi all mac bumbers i have abanded the bumb for just putting a fair bit of pressure with the winch . on a 20 minute drive from ramp to home i stop 2 to3 times and re tension the winch, i find the x slides foward to fit securely in vee rubber. the x is being carried on a 2 axle trailer not sure if that helps. regards uncle trev

[Snyds]

Anyone have a picture of a winch mod that works????? I put a new one on last year and it stripped the gears right away (thank God the first thing I did was place a saftey chain), not sure what way it originally sat since the previous owner was a mod machine!
Thanks as always!
Steve

[Hamin' X]

Anyone have a picture of a winch mod that works????? I put a new one on last year and it stripped the gears right away (thank God the first thing I did was place a saftey chain), not sure what way it originally sat since the previous owner was a mod machine!
Thanks as always!
Steve

A quick search of the Mac Mods, using the search term "winch" and under the Trailer category reveals:

Relocate Trailer Winch, by Tahoe Jack. Although in the mod Jack uses a new winch, you can reuse the existing winch, the handle will just crank backwards.

~Rich