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I have deployed a slightly different protocol. Because I have bottom paint, the Mac bump is virtually impossible to accomplish in the space near my usual ramp. The boat just won't slide all the way into the V, and, yes, even when winched up into it at the ramp, it slips back about six inches by the time we are level. Therefore, I use a ratcheted strap from the bow eye down to the trailer together with a very tightly winched in trailer strap at the bow. I use two ratcheted straps at the stern. Each goes from the trailer to the aft dock cleat and is ratcheted tight. The only time that system showed its obvious weakness was one time I was in north Georgia going down a steep hill with a traffic light at the bottom. It turned red suddenly, and I hit the brakes and DID get the Mac bump due to the weight of the boat and the degree of the incline on the hill (and my speed). The aft straps did loosen slightly as a result as the boat shifted forward. But for generally flat towing, I have never had an issue.

Similar issue with bottom paint making the "bump" maneuver near impossible at under 30 mph.

I have ordered some of this in hopes it will help.
https://www.crcindustries.com/products/ ... wt-oz.html

A double strap also sounds like a great idea.

Successful 145 mile tow with two straps plus extra bow eye strap. Thanks for all of the advice.

Glad you made it safely! Looks like a nice rig!

Agree Mac Bump has limited success with bottom paint and ‘anti skid’ truck brakes. I replaced my top engine mount bolts with eyebolts - attach ratchet strap from these with a bridal and route underneath Mac to the front tongue structure (pulls forward more than down). Strapping to the stern cleats was causing gel coat damage from strap flutter. I pull over and retention bow and transom straps every 10 miles or after railroad crossing/ pot holes event. Within 50 miles the Mac has moved forward 6” and in proper position.

Hi Closehaul

Love your idea and approach!

Yes the Mac Bump is useless with bottom paint!

We’ve been using the 3” wide HF strap up and over the pedestal & cockpit. (Just about every state requires aft securement straps for boats but enforcement varies by jurisdiction and time of month (generally for “revenue generation” purposes ).

The ‘pull fwd’ approach you describe looks promising!

Another approach we’ve been considering is articulating our fwd winch post roller bracket with a Jack screw arrangement (instead of our multi “trial and error” loading approach of getting the bow close enough to the roller we’ve been doing.

We’ve also looked at adding “plastic glide strips” to our bunks but after looking at other trailers with those have seemed to be quickly torn up by the bottom paint.

Best Regards
Over Easy

My 26S was damaged on the trailer, not tied down 11 Km to house hit a deep pothole when the boat came back down the hull touched the mid point cross over and cracked the bottom in the balast water tank area all my fault. So now I use 2 ratchet tiedowns one on either side rear from the rear tie down cleats to the trailer frame just behind the back of the tires and the saftey strap to the bow eye and the winch up snug as well, 3 point tie down but it hasent moved since. The Mac bump is required to move the hull to the proper towing position, anything farther back leads to trailer sway that's more of a problem and scarey as hull.

Just as an FYI to anyone interested...

We took the opportunity to reposition our fwd bow hull roller support on our Sea Lion trailer several week ago.
As previously mentioned we have (non-copper) ablative bottom paint as we use Over Easy in Salt/Fresh water for extended periods of time and also store/travel with Over Easy on the trailer.

I'd gone through several attempts at the ramp to get Over Easy to sit up into the winch post 'V" roller once we were up and out. This required us supporting the bow by the fwd bow eye via the winch cable (not something I wanted to do indefinitely ).
I then looked at the relationship of the fwd bow bottom support roller. there was about a 3 inch gap between it and the hull. We took the opportunity to unbolt and raise this support roller up to make solid contact with the hull. We also noted exactly where the winch post "V" roller was located relative to our bow...exactly in line with the chine. Now when we recover load Over Easy onto the trailer we made it a point of winching her on and up to align the winch post "V" roller with the bow chine before finishing our haul out. This has made a significant improvement at eliminating the prior fwd gap in this region. Happy Days!

We can even back off the winch cable tension to slack and Over Easy stays ing full contact with the winch post "V" roller AND the fwd bottom roller support. This has eliminated the prior idea of making an articulated arm concept for the winch post "V" roller we had been considering.

Here one can see the overall end result:

Bow tight against the winch post “V” roller:

Fwd hull now resting fully on the trailer fwd bottom support roller:

Detail of repositioned trailer fwd bottom support roller showing how the bolts are now above the plate effectively interference “locking” the now raised support roller from ever slipping down out of position in the future:

(Yes, there are now only two bolts clamping the bottom roller bracket in position instead of the original four. The actual roller sliding support is VERY robust heavy gage and has a formed angle structure on each side to stiffen it. The significant relevant force exerted on the bracket is downward which is not only taken up by the two lower clamping bolts but now also taken up by the two upper bolts now placed in interference shear between the sliding plate and trailer mount plate. The small relative moment arm formed by the roller axis vs the slide plate interface is more than adequately addressed by the tensile capacity of the two clamping bolts and the roller plate geometry. The relative downward force exerted by the boat onto the support roller, negating any other supporting contributions by the winch cable, is about 200-to-300 lbs based upon the amount of leveraged force needed to vertically displace the bow vertically while getting this all fitted into position while Over Easy sat on the trailer. The vast majority of the vessel weight being carried by the four longitudinal bunks upon which Over Easy rests when on the trailer. Any in transit downward loading is addressed by the frictional clamping interface of the lower two bolts and the shear loading of the upper two bolts. Any in-transition shock loads induced when loading contact is made by the hull riding up the support roller in the fwd direction is minimal as the boat is afloat and the moment arm offset is minimal and entry contact is across a progressively engaged tapered surface of the hull to a freely rotating roller. This note provided for those interested in whether there was any structural/mechanical engineering design considerations given to this modification/adjustment. Summary: More than good enough! )

Results:
No more concerns about having a bow/ roller gap to the winch post “V” roller or bottom support roller.
No more multiple “up/down” runs back & forth runs “on-ramp” to get Over Easy situated on her trailer for transport.
Now just a consistent uniform process with consistent results!
Happy! Happy! Happy!

Hope this helps someone with similar issues/concerns.

Best Regards to All
Over Easy