EXPLAIN PLEASE - Mac Bump (trailer)

A forum for discussing issues relating to trailers and towing MacGregor sailboats.

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Idle Time
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Post by Idle Time » Wed Mar 29, 2006 9:13 am

Sound like that would work...if my bump doesnt work next time ..I'll try it that way...unless there are several boats waiting to load or unload...

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ralphk
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Mac Bump

Post by ralphk » Wed Mar 29, 2006 3:48 pm

Two additions:

1) I pull out with moderate tension on the winch and initially accept that the bow will be a good foot from the rubber V. Any leftover ballast water drains.
After pulling out, I derig, secure everything for the trip in the parking lot. Even though I'm getting faster with practice, it's likely near an hour, not 20 minutes as described by the Speedy Rigger guy. By then the pads are dry, so I back up one more time to the ramp, soak the rear pads and barely float the Mac. Winching the second time, the Mac stops within 3 or 4 inches of the "V". Now everything is secure, slippery and ready to "Bump"

2) I prefer to do the Mac Bump on a little downhill slope near our local marina. Several times last year, I had her ease forward into the "Y" stop so smoothly that you barely feel it in our Pathfinder ie: sans bump.
Required speed is less and I'm convinced that there's less strain on the truck brakes.


MAKE SURE THAT THERE IS NO ONE BEHIND YOU!!

Ralph
Hakuna Matada '96

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Tom Spohn
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Post by Tom Spohn » Thu Mar 30, 2006 12:30 pm

Make this an easy operation by putting "Liquid Rollers" on your bunks before loading the Mac. Works like a charm.

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Win
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Post by Win » Thu Mar 30, 2006 3:58 pm

Tom Spohn wrote
Make this an easy operation by putting "Liquid Rollers" on your bunks before loading the Mac. Works like a charm.[/b]
Tom, how often do you spray your bunks?

zuma hans 1
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Post by zuma hans 1 » Fri Mar 31, 2006 2:42 am

Ohhhh, this is smart.

Since we use a hoist all the time this problem had never presented itself, until last month when we trailered to San Pedro.

We refloated the boat to snug it up.

This McBump is marvelous!

Of course, the obvious question is: do blue macs bump faster?

Bill ( My Pleasure)
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Post by Bill ( My Pleasure) » Fri Mar 31, 2006 3:43 am

I wonder if anyone has tried to use a winch external to the trailer, for example, set-up in the bed of a pickup. How about putting the winch in a better position on the trailer? As previously stated the winch pulls the boat down, not forward. I live a block away from a trailer shop. I thought of having them modify the trailer, but I always get concerned about the possibility of a lawsuit if something went wrong on the highway. Bill

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Chip Hindes
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Post by Chip Hindes » Fri Mar 31, 2006 9:24 am

As previously stated the winch pulls the boat down, not forward.
Actually, I believe it's by design that the winch pulls the boat both down and forward.

The Mac trailer flexes quite a lot under road loads, and I like the idea the boat is being held snug against the roller in both directions.

I've seen it recommended to actually chain the bow eye downward to the center rail; some of the rigs even have a turnbuckle to tension said chain. Combined with the flexibility of the trailer, I think this could put tremendous loads on the bow eye, so for the Mac and stock trailer I'm not sure it's a good idea.

ken smith
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larger winch

Post by ken smith » Sat Apr 01, 2006 3:27 pm

My simple solution was to put on a larger winch. The winch pulls the bow right up to the v and stays there no bump needed and I can retrive the mac in less water because of the greater power of the winch. The mac will even winch the mac up with full ballast.
Ken

RobinsonCruiseOh
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Re: EXPLAIN PLEASE - Mac Bump (trailer)

Post by RobinsonCruiseOh » Tue Jul 24, 2018 2:16 pm

Oh man. I've sailed 6 times or so on my new-to-me 26D and just now heard about the "Mac bump". I was complaining to my wife about the stupid geometry of the trailer + inclined launching ramp + boat floating level and wondering why other boats don't have this problem. Then someone on FB posted a picture with reference to a "mac bump gone wrong" and I couldn't figure out what they were talking about.

Huh. Well looks like I'll try this next time. Might save the painfully slow process of re-floating after emptying the ballast to try to get it lighter so I can pull it tighter.

Nauti Nell
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Re: EXPLAIN PLEASE - Mac Bump (trailer)

Post by Nauti Nell » Wed Jul 25, 2018 5:32 am

RobinsonCruiseOh wrote:Oh man. I've sailed 6 times or so on my new-to-me 26D and just now heard about the "Mac bump". I was complaining to my wife about the stupid geometry of the trailer + inclined launching ramp + boat floating level and wondering why other boats don't have this problem. Then someone on FB posted a picture with reference to a "mac bump gone wrong" and I couldn't figure out what they were talking about.

Huh. Well looks like I'll try this next time. Might save the painfully slow process of re-floating after emptying the ballast to try to get it lighter so I can pull it tighter.

I posted that pic on FB. Here's the link for those in the group that didn't see it or don't belong to the Mac grp on FB.

https://www.facebook.com/DixieHicksComm ... pe=3&ifg=1

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NiceAft
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Re: EXPLAIN PLEASE - Mac Bump (trailer)

Post by NiceAft » Wed Jul 25, 2018 6:55 am

RobinsonCruiseOh said:
Well looks like I'll try this next time. Might save the painfully slow process of re-floating after emptying the ballast to try to get it lighter so I can pull it tighter.
If I understand correctly, you float your craft onto the submerged trailer before emptying the ballast. If that is correct, do not attempt the Mac Bump. You must empty the ballast first, preferably while in the water before motoring onto the trailer. This makes it easier to crank the bow closer to the rubber pad, and a smaller distance to move the boat with the “bump”.

Slowly get up some speed, and step on the brakes hard. Too fast, and the boat is in your back seat. Too slow, and nothing happens. The Goldilocks speed is just right. Good luck.

Ray

K9Kampers
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Re: EXPLAIN PLEASE - Mac Bump (trailer)

Post by K9Kampers » Wed Jul 25, 2018 5:33 pm

Remember to first loosen the bow winch line before bumping, then tighten the line after the boat is where you want it.

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March
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Re: EXPLAIN PLEASE - Mac Bump (trailer)

Post by March » Wed Jul 25, 2018 7:08 pm

You're playing Russian Roulette with the MacBump. It might work twice, or ten times, but it's enough to miss the golden window of opportunity just once: the boat has plenty of inertia even without water ballast. You go a mite too fast, or the boat dislodges itself too easily, or you're slamming the brakes too enthusiastically, or the strap is three inches too long, or there's a slight slope in the parking lot--and wham! the boat slides merrily and breaks your central post (which even so, is a wee bit too flimsy) and ends up on your back seat. This is what happened to us in Florida last year. No more MacBum for me

It is safer to empty the ballast, back up and float the boat again, tighten the strap, and repeat--if necessary. Even if you have a couple of inches between the roller and the nose of the Mac, as long as the boat sits snugly on the trailer, especially if you have an additional safety chain.

But I fully agree with Chip: the whole boat is anchored only by the bow eye. That's always a nasty thought in the back of my mind. Additional straps from the back to the vertical posts

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NiceAft
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Re: EXPLAIN PLEASE - Mac Bump (trailer)

Post by NiceAft » Wed Jul 25, 2018 7:21 pm

After thirteen seasons I still perform the bump.

Whether or not you do the bump or not, a strap around the boat and trailer at the stern in a must, at least in my mind.

Securing the boat to the trailer and loading the boat onto the trailer are two different issues.

As to the bump; some will, some won’t. It’s a personal decision. RobinsonCruiseOh inquired about it. He now has opposition opinions. Neither is wrong, just different opinions.

This site has come through for him.

Ray

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kmclemore
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Re: EXPLAIN PLEASE - Mac Bump (trailer)

Post by kmclemore » Wed Jul 25, 2018 10:34 pm

The MAC BUMP is not just with Macs. I have a brand new Tahoe 550TF and it also needed the “bump” the other day when I hauled it out.

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