A liitle Feedback with respect to the MAC Bump

pcmb · Post by **pcmb** » Thu Apr 17, 2008 2:27 pm

On an earlier post I asked the question about the Gap after having retrieved the boat on the trailer.

Thanks everybody for your inputs.

This last weekend I retrived the boat and did end up with some problems.

As I had indicated before the boat is antifouled - but is clean

I used washing up liquid on the carpet of the wooded boards - This may have been a mistake - it may not be the same as using soap. To cut a long story short - I could not get get rid of the Gap. The Gap was about 7 inches. I was driving at 20Kms and braking - the boat would not budge. I re-floated the boat about 10 times to make everything wet again -still no luck.

But I did learn something and think I Have a way to retrieve the boat without doing the mack bump and wanted to share this with you.

After 10 unsuccessful tries I replace the V shaped rubber wedge with a roller. I then re-floated the boat and started to winch the bow to meet the roller (instead of the rubber wedge) I found that I could continue winching with the effect of pulling the bow higher up on the roller to its correct position. This is because the roller would rotate allowing the bow to come higher out of the water which could not be done with the rubber wedge.

I then pulled the boat out of the water and there was no gap.

I probably will replace the winch with a more sterdy one but this seemed to work very well.

Again thanks for everybodies help

Post by **NiceAft** » Thu Apr 17, 2008 3:22 pm

PCMB,

Did you step on the brakes HARD

You really have to mean it when you brake. Slam them if you have to. Your not going fast enough to skid.

Objects in motion tend to stay in motion. Newton's law is the principle being used here. Did you break that hard?

Ray

Boblee · Post by **Boblee** » Thu Apr 17, 2008 3:42 pm

Ray I can sympathise with pcmb as I had the same experience "once" and believe me I stepped on the brakes hard even going down the steep ramp nose first and our boat is not antifouled.
Am surprised though that the dishwashing liquid didn't help, not sure whether a bigger winch is a good idea but am putting a roller just in front of the front berth to help it roll up.
Also think getting the trailer deeper into the water is a must, where possible hopefully will be able to report on a couple of other mods in a couple of weeks too.

PatrickS · Post by **PatrickS** » Thu Apr 17, 2008 5:09 pm

NiceAft wrote:PCMB,
Did you step on the brakes HARD

I for one will advise against the Mac bump. I bent my ladder that way. If you use dishsoap mixed with water in a spray bottle, you should be able to winch it tight with no problems. It may take one or two pauses when hauling out to winch it up a bit each time, but that's the safe (and I think proper) way to do it.

I know lots of folks successfully use the Mac bump, but its also a good way to mess up your ladder.

Post by **NiceAft** » Thu Apr 17, 2008 5:53 pm

I am sorry to hear of the problems some have with the MacBump. Do what you need to do. What ever works

Ray

pokerrick1 · Post by **pokerrick1** » Thu Apr 17, 2008 6:51 pm

And I for two highly recommend the McBump - - - when done correctly I've never seen it fail - - - and it's even in the manual

In any event, if youy search McBump (MacBump?) you SHOULD come up with a wealth of hits and maybe find that you're overlooking something

Rick

tlperrine · Post by **tlperrine** » Thu Apr 17, 2008 9:27 pm

The biggest problem I ran into with the Mac bump was being timid. I had to nearly lock up my Jeep Cherokee brakes to make it work. Just my experience. Just make sure all the water is out of the ballast tanks. I didn't have to soap the bunks or do anything special. Just hit hard on the brakes and have plenty of room to perform the stopping procedure.

pokerrick1 · Post by **pokerrick1** » Thu Apr 17, 2008 9:32 pm

tlperrine wrote:The biggest problem I ran into with the Mac bump was being timid.

Exactly

Rick

c130king · Post by **c130king** » Fri Apr 18, 2008 3:57 am

What Rick said

Jim

(* Sorry Rick...couldn't resist *)

Craig LaForce · Post by **Craig LaForce** » Fri Apr 18, 2008 4:41 am

I never got the bump to work, and winching tight while in the water also doesn't work because the winch support (ladder) and winch line simply "gives" allowing the boat to drop back a few inches.

Mine has Antifouling paint on it and even with dish soap it doesn't move.
I am thinking of putting a small 12V winch up in the bed of the pickup truck to help with boat retrieval as well as to help pull the jib hayard to put the jib on the furler and also to raise and tension the mast without putting together the mast raising system.

PeteC · Post by **PeteC** » Fri Apr 18, 2008 7:16 am

I like pcmb's solution the best. Crank it up tight when loading and be done with it.

Macbump never worked for me, though I am probably too timid.

March · Post by **March** » Fri Apr 18, 2008 9:05 am

Two years ago, I pulled the Mac out of the water on a pretty steep ramp. After we de-rigged it on shore, I realized that I had forgotten to activate the "stopper" on the winch. The boat had slipped back abpout 3 inches (the ballast was still in) but it still looked like it had settled securely on the trailer.

I panicked realizing how easy would have been to lose the boat off the trailer as I was pulling her out of the water. Buit then it occurred to me that, since I didn't, the boat is well balanced on the trailer as it is. A gap in front doesn't seem to make all that much difference.

Of course, now I always make sure to check the stopper twise--and have added an extra safety line while trailering. Even so, that makes me feel a little better abouyt not being able to perform the Macbump--that has never worked for me anyways

John Christian · Post by **John Christian** » Fri Apr 18, 2008 9:59 am

PCMB,

After searching this forum and reading all the advice, I came up with two steps that will ensure "Mac Bump" success:

First, disconnect the winch strap, it is actually working against forward movement,

Second, get an adjustable trailer hitch and lower it all the way. Mine has about an 7" drop when lowered fully. The boat will move forward much easier and won’t require an aggressive “Bump”

The hitch is also invaluable for getting the load on the hitch right and decrease the trailer sway.
Adjustable Hitch Do a search on "adjustable hitch" and you’ll find a ton of great information.

regards,

JC

Frank C · Post by **Frank C** » Fri Apr 18, 2008 2:31 pm

March wrote:. . . I panicked realizing how easy would have been to lose the boat off the trailer as I was pulling her out of the water. Buit then it occurred to me that, since I didn't, the boat is well balanced on the trailer as it is. A gap in front doesn't seem to make all that much difference. ...

March's advice is valid for his boat, and any Mac with a 50-horse motor, or less.

But those with oversized motors must be more careful about loading the boat fully forward onto the trailer. The outboard is (obviously) mounted at the farthest possible point aft. Therefore, the extra 100 or 150 lbs. of a larger outboard is creating a sizeable aft lever-arm. This can significantly alter the tongue weight of your trailer, and consequently, towing stability.

Boblee · Post by **Boblee** » Fri Apr 18, 2008 3:37 pm

JC
Have been looking for something like that for ages and couldn't find it.
In desparation was going to make one but for the price and the simplicity why bother?
Thanks for putting that up as IMO that would be one of the most helpful moves to getting the boat on the trailer and the bump working especially on our very steep Northern ramps.
All I need to do now is find one in Aus.

MacGregorSailors.com

MacGregorSailors.com

A liitle Feedback with respect to the MAC Bump

A liitle Feedback with respect to the MAC Bump

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