A liitle Feedback with respect to the MAC Bump

[Hamin' X]

Just went out and looked at my trailer and the ladder will be in the way with the existing winch, turned over. Perhaps the winch could be disassembled and put back together backwards, by drilling a new hole for the ratchet stop, but I think it would be easier to replace the winch.

~Rich

[Snyds]

Thanks Rich! I tried to find some but I couldn't find it... I blame my iPhone!
Steve

[bubba]

I installed black polyeurithane strips to my trailor boat supports, there slick enough for our bottom paint to slide and only needs a little bump to get in to place then I need to use 3 inch straps foward and aft to secure the boat from moving around too easy when on the road. I think most trailor parts magizines have these parts.

[Starscream]

The bump has never worked for me. I can jam on the brakes as hard as I can, and the boat won't move. I just tow it around with a 5" gap between the nose and the V. I slip a 2x4 and some carpet in between so in case of a severe stop... or, heaven forbid, accident... so the boat won't get enough momentum to break the V support and come in through the back window.

One comment/question: on a recent trip to a new location with the boat, I hauled out on a relatively flat beach, which resulted in the nose of the trailer being only an inch or so from the V when I got it onto the road. I noticed the rear of the truck was much lower with the boat in the forward position. I didn't think the few inches would make so much difference. I'll see if I can figure out the difference in weight on the hitch and post it later. I liked the trailer position better when the boat was farther back. The boat was heavily loaded at the time with a week's worth of groceries, batteries, gas, luggage for 6. (dual axle!!!)

[The Mutt]

The bump didn't work for us, I think it's the antifouling sticking to the carpet, next time 'Imagine' is off the trailer I'll be adding some UHMWPE skids.

Glenn

[restless]

Nevre really understood the bump.. I do it occaisionally if there's a gap of a couple of inches, though most of the time she comes out with her nose pressed into the rubber, mind, our local slip is pretty shallow. We use a 20m rope to haul her out.

I'd be most curious to know how the rig behaved with a lighter nose weight.
From a uk post:

2 ton = 2000 Kg
7.8mt = 780 cm
2000/780 = 2.5 Kg/cm
It means that bi moving the boat 10cm (4") forward or backwards you only move 25 Kg.

I'm not sure one can apply this formulea exactly as I'm feeling there is some simple physics that deals with center-of-gravity-relative-to-a-fulcrum forces. All a bit mysterious.. I just hate trailer grief!

[LakeSuperiorMac25]

End to the Mac Bump.
I added about 8" in height to the trailer's winch. This allowed to crank the boat up tight while in the water, and keep it there, even when the winch tension was released. Adding the height meant getting a piece welded on. Don't skimp. Get it welded by someone with a deep penetration welder.

[March]

Never worked for me either. I was considering slicking up the strips (polyurethane or something) but then I thought it would be better to have some traction on the trailer. I forgot to secure the winch once as I pulled the boat out of the water; it slipped back some 5 inches and still stayed on the trailer. I shudder thinking what would have happened if the strips had been slicker--but not as slick as to allow it to slip back into the water on the ramp.
The gap is about 3 inches. I secure it with a second steel cord that goes right into the prow ear. The other end is fastened securely to the ladder support.

[Divecoz]

I spray my bunks with Spay foam tire shine about once a year. It sure makes that Indoor outdoor carpet on all my bunks deadly slick.. I still tap the breaks just to set her in... so to speak and then chain her down (chain is required in some states ) Not in ILLINOIS but I do it anyway..

[raycarlson]

added second bow eye 8 inches lower, pulls up on bow when winching rather then pulling down on old bow eye.don,t know why macgreg factory couldnt figure this out

[Paul S]

added second bow eye 8 inches lower, pulls up on bow when winching rather then pulling down on old bow eye.don,t know why macgreg factory couldnt figure this out

The figure the factory trailer will last 6 launches and wanted the bow eye in the right place when you get a 'real' trailer

[Paul S]

Never worked for me either. I was considering slicking up the strips (polyurethane or something) but then I thought it would be better to have some traction on the trailer. I forgot to secure the winch once as I pulled the boat out of the water; it slipped back some 5 inches and still stayed on the trailer. I shudder thinking what would have happened if the strips had been slicker--but not as slick as to allow it to slip back into the water on the ramp.
The gap is about 3 inches. I secure it with a second steel cord that goes right into the prow ear. The other end is fastened securely to the ladder support.

putting soap on the bunks helps a LOT. I just squirt dishwashing detergent or car wash soap (whatever i have on hand) liberally on the bunks.. make sure ALL the straps are loose (but not detached).. drive and brake sharply.. the boat should slide up..tighten the straps then..drive home. If the straps are tight, the boat won't move..

[Retcoastie]

added second bow eye 8 inches lower, pulls up on bow when winching rather then pulling down on old bow eye.don,t know why macgreg factory couldnt figure this out

That is what I thought would work. But, I just could not get myself to do it. I took the idea of an upward pull and did this instead.

http://www.macgregorsailors.com/modt/in ... ?view=1430

Same result. No holes in boat.

Ken

[Freedom77]

Once again "FUN" ramp experiences. Pickup driver decided to BUMP bow forward at Marina Del Rey on weekend. Got up to about 35 mph in the parking lot and crammed on the brakes. Boat broke off winch mounting and ended up the bed of the pickup. OVERKILL!!!

[pokerrick1]

Yes, there are idiots everywhere- - - 5 MPH is plenty. The MacBump has NEVER failed to work for me - - - and that's without any alteration to the bed of the trailer or lubricants

Rick