A Possible Solution for the "Mac Bump"

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Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
When we would retrieve our S it would pull right up to the "V" snubber block on the trailer in the water. Coming out of the water it would rotate on the bunks back away from the "V" a couple inches. The anti-lock brakes on the Suburban made it hard to execute the "Mac Bump" so we usually towed it with it sitting a couple inches back. In fact we towed it 2200 miles back from Florida that way without a problem, but still I didn't like it.

It finally dawned on me that if I couldn't get the boat to the "V" block maybe I could get the "V" block to the boat so I modified....



...the trailer to do just that...



with the piece above. At the same time I made a couple other...



...mods to the front of the trailer to handle a problem that surfaced when I added the double anchor roller to the bow of the boat.

The mods are here.....

http://purplesagetradingpost.com/sumner/macgregor-trailer/trailer-mods-17.html

Remember if you want to do this you don't have to do it exactly as I did and still get the same results,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links
 
Sep 26, 2010
808
Macgregor 1993 26S Houston
Hey Sumner,
I thought I saw somewhere that you had installed another roller on your trailer, close to the bow?
I thought that roller would raise the bow when going onto the trailer and solve this issue.
I have been planning on doing it too because of that. I just haven't got a round tuit yet.
??
Jim
 
Feb 20, 2011
7,990
Island Packet 35 Tucson, AZ/San Carlos, MX
Boy, did I pique the interest of the local lot watcher when I tried to execute the "bump".

Like my wife, sometimes I get compulsive about silly little things. It rode the 140 miles back home just fine. Anyone found the bump to be really necessary, or is it just our obsessive nature?
 
Sep 26, 2010
808
Macgregor 1993 26S Houston
Boy, did I pique the interest of the local lot watcher when I tried to execute the "bump".

Like my wife, sometimes I get compulsive about silly little things. It rode the 140 miles back home just fine. Anyone found the bump to be really necessary, or is it just our obsessive nature?
I have towed home a few times with the bow a few inches back, and I don't like the way the boat rocks on the trailer.
Like Sumner, my antilock brakes sometimes make it hard to get it sliding.
I find if I get going faster it woks better! People look at me like I'm crazy though. especially if I have to go for a 2nd or 3rd try.
Then sometimes I get more sliding than I want.
Sumner's mod let's you get a custom fit. That's pretty cool.
Jim
 
Feb 20, 2011
7,990
Island Packet 35 Tucson, AZ/San Carlos, MX
I have towed home a few times with the bow a few inches back, and I don't like the way the boat rocks on the trailer.
Like Sumner, my antilock brakes sometimes make it hard to get it sliding.
I find if I get going faster it woks better! People look at me like I'm crazy though. especially if I have to go for a 2nd or 3rd try.
Then sometimes I get more sliding than I want.
Sumner's mod let's you get a custom fit. That's pretty cool.
Jim
She'd rock on the trailer? I assume you mean fore and aft rocking, not side to side? I have another winch mounted on the trailer tongue, that holds my pulpit railing down onto the trailer bed. I'll admit, it was only once my Sovereign didn't come forward enough on the trailer for my ignorant comfort level.

Sumner has certainly got customizing down in spades, and his engineering always looks very sound.
 

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
Hey Sumner,
I thought I saw somewhere that you had installed another roller on your trailer, close to the bow?
I thought that roller would raise the bow when going onto the trailer and solve this issue.
I have been planning on doing it too because of that. I just haven't got a round tuit yet.
??
Jim
The bow roller helps to get the boat forward...



...when it is in the water and keeps the bow up out of potentially hitting the trailer. Above you can see that the boat is on the roller and up in the "V" while the stern is still in the water. Once I have the boat/trailer pulled up in the parking lot it is usually about 2-3 inches back. I think what happens is that as the trailer comes out of the water the boat settles onto the forward bunk. Then starts to rotate around it. Then as the trailer comes out further it rotates around further and down onto the back bunk or in the case of our trailer with 3 bunks now the back two bunks. The only way that I see how it does this is that it pulls the web strap tighter in the winch, letting the boat go back as it pulls slack out of the strap.

The bow roller does help, but in our case has never stopped the boat from settling back away from the "V" block. I'm always driving and have never actually watched what is going on as the trailer comes out of the water. Also I put the roller on before we ever launched for the first time. I have raised the roller just a little as was shown on that page hoping to help the whole situation with the rocking. I never wanted to really put a lot of the boats weight on the roller as the load is pretty much a point load and not spread out much. Still the hull should be quite strong there.

Without the boat in the "V" it does rock up and down when you hit bad sections of highway, like bridge approaches. It was really bad on the Interstate in Mississippi coming home. That finally did it and I decided to try this. I won't know how well it works probably for a year until we use the boat next. If I was towing a few miles I wouldn't worry about it, but when you hit a really bad section of road and see it go up and down it is unsettling,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links
 

walt

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Jun 1, 2007
3,511
Macgregor 26S Hobie TI Ridgway Colorado
Just be a little careful... if you have the single axle trailer, where the boat sits will affect tongue weight and how the boat tows. An inch or two makes a significant difference.

The bow roller was one of the first things I did about four years ago when I got my 26S (got the idea off the internet - used to be a web page with pictures of a bunch of peoples mods) and it makes a big difference especially if the ramp you use is a little steeper. One ramp I use was fairly steep and what would happen is that the boat would rest on the forward stock V cross beam but the boat and the trailer would be at significantly different angles. So when you tightened the strap, at some point, it was trying to pull the bow UP rather than forward and of course you cant pull the bow up.

The bow roller being forward is where the boat will contact the trailer and it gets the bow eye strap more in line with the winch. The more forward you have the bow roller, the more forward you can get the boat on the trailer with the winch while in the water.

I like Sumners idea - looks like it would be good before you did a long trip to secure things. Ive also towed long distances with the boat sitting back an inch or even two from the bumper.
 

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walt

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Jun 1, 2007
3,511
Macgregor 26S Hobie TI Ridgway Colorado
Sumner, maybe this was already your original intention - but it also occured to me that if you can move that bumper forward before putting the boat on the trailer - and then move it back "to fit" after the boat was on the hard, this would in general put the boat more forward on the trailer.

How far forward of the stock bumper position will that sliding configuration go? Even an inch probably would be a benifit..
 

chp

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Sep 13, 2010
418
Hunter 280 hamilton
Glad this one came up. I always thought it was just me. I too have a bow keel roller which was installed on the trailer when I bought the boat. It didn't do anything because the PO had it down all the way. I adjusted it as high as it would go and this really helped. I will have to do a slight mod to get it evern higher. I also realized the strap stretches when pulling the boat out. I installed a turnbuckle attached to the trailer and a hook on the other end to attach to the the bow eye. With this I was able to get the bow within about 3/4" of the bow stop. However as we just did our first trailer trip, I found it a bit harder to get the boat all the way up due to the different ramp angle. Have to admit I didn't know what the Mac bump was. Never tried that one. I was draining the tank and putting the boat back in the water to get it tight to the front originally. One of these days I will have to get a welder to keep up with the mods I still want to do. Boats are a great excuse for new tools and the mods keep the wife happy. Once the boat is out of the water for the season I will post my mods. Hope Sumner doesn't mind some of the similarities in some of my mods.
 

caguy

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Sep 22, 2006
4,004
Catalina, Luger C-27, Adventure 30 Marina del Rey
Sumner, maybe this was already your original intention - but it also occured to me that if you can move that bumper forward before putting the boat on the trailer - and then move it back "to fit" after the boat was on the hard, this would in general put the boat more forward on the trailer.
That step was included in his mods article.
I also found that lowering the trailer ball with a 6" drop insert made a big difference on loading the boat.
 
Dec 14, 2008
92
Tartan 30 Bayfield, WI
The rig at the front of my trailer really has never needed the "Mac Bump"
As the boat is in the water and the trailer is under it, the winch strap pulls the bow high onto the V-Stop...

https://picasaweb.google.com/lh/photo/LBxAd2zjWKPN0jJndXjOWQ?feat=directlink

Then, once the boat is pulled out of the water…and the bow raises slightly…the winch strap is removed and run through the lower roller as well and winched tight to bring the bow back down…

https://picasaweb.google.com/lh/photo/amjlRya7lxUWkYdQXErWtw?feat=directlink

This brings the bow in contact with the V-Stop…thus eliminating the need for the bump.
I am always way over prepared so I cinch it down with a rachet strap over the pulpit and add a chain…that boat is goin’ nowhere.

https://picasaweb.google.com/lh/photo/vVezbEVDmoNL-A2X6CHo3Q?feat=directlink

***Sorry...I tried to embed the images, but could not make them as professional as Sum***
 

walt

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Jun 1, 2007
3,511
Macgregor 26S Hobie TI Ridgway Colorado
I know I have much more trouble on steeper ramps.. backup looks like a good idea.

I like that idea to get the hitch lower.. anything you can do to get the trailer more parallel with the boat when you tighten that strap is going to help. I think someone also posted in the past that the boat tows better if the bow is down a little. I’ve never messed with this but seems also a positive thing.
 

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
The rig at the front of my trailer really has never needed the "Mac Bump"
As the boat is in the water and the trailer is under it, the winch strap pulls the bow high onto the V-Stop....


Is that trailer stock? I've never seen one like that. I considered mounting the winch lower on the ladder to get it out of the way more and then running the strap through/over a roller similar to do that. I'll see how what I've done works first though.

I didn't like the boat rocking up and down on rough highway sections on trips. I could of winched it down tighter at the bow, but felt it was trying to rotate the boat on the forward bunk and lifting it at the rear and didn't like that much strain on the bow eye on the boat.

I also put a chain on the bow for backup to the strap. I want to end up with the boats weight on the three bunks and the strap just holding it into the V with the V and the bow roller eliminating any up and down rocking. I think we might be there now. I've never seen any damage to the boat over the 8,000 to 9,000 miles we have towed, but didn't like watching it load and unload the bunks/bottom of the boat on rough road sections.

Walt the "V" will be slid a couple inches forward while loading and then once the boat settles with the boat/trailer up on land it will be pushed back against the bow. I think then it will be about where it would be if you had the stock setup and then did the 'bump'.

Like Nelson said on the other board I don't like the bump as then you are creating a dynamic load if you can get the boat going forward which I have a hard time doing anyway.

I just posted another page on why I think the 'gap' appears......



..... even when the boat is in the "V" while the boat/trailer or in the water. It is here....

http://purplesagetradingpost.com/sumner/macgregor-trailer/trailer-mods-17-a.html

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links
 
Sep 26, 2010
808
Macgregor 1993 26S Houston
I find it helps to have the trailer out of the water enough that the boat will only float up to within a few feet of the V. Then I winch it the rest of the way. That way it's mostly sitting on the bunks while still in the water, and minimizes the rotating when you pull out.
I also blow the water out of the ballast tank before I put it on the trailer.
That's 1200 lbs I don't have to pull up onto the trailer, and up the ramp.
A $10.00 air mattress inflator works good, and is faster than one would think.
Sometimes it still ends up a few inches back.
Jim
 

Sumner

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Jan 31, 2009
5,254
Macgregor & Endeavour 26S and 37 Utah's Canyon Country
Oct 21, 2010
350
Macgregor 26S, "Myuna" Brisbane, Australia
The bow roller being forward is where the boat will contact the trailer and it gets the bow eye strap more in line with the winch. The more forward you have the bow roller, the more forward you can get the boat on the trailer with the winch while in the water.
This is the bit I am unsure of Walt. I had intended taking my lead from Sumner (who as usual has been of immense help) and placing the bow roller, on the forward part of the trailer, 61" back from a verticle line from the bow. Observation during haul out made me think it might work better if about 47-51" back (not sure why I was so precise with those numbers - but just notes I had made from time to time). How far back is your bow roller? Does anyone else know the exact position of their bow rollers?

I have had my boat on a hard stand at the marina for the first 12 months but have now brought it back home to put it under the house and do some repairs and mods for a few months. As the marina guys do the putting in and out with the tractor I have been in a position to just sit back and observe what happens during the process - plus get some valuable input from the haul-out guys. There are no other 26 Classic at the marina but there are about four or five 'X's and 'M's.

It appear to me that the advantage of the bow roller would be that it keeps the bow up in the air and allows it to be brought closer to the V-notch - otherwise the stern floats in the water and thus does not allow the bow to rise up. Before I pulled the boat home we put it back in the water without the water ballast in and then progressively winched it up towards the v-notch in about 3 stages - moving the boat forward a couple of feet each time. I often had the bow 100-150mm back from the V-notch when it was just being kept in the trailer yard near the water (never feel very comfortable with that idea when we got strong winds down there).

The reason the bow usually sits 75-100mm back from the V-notch appears to be a lot to do with the flex in the front arms of the trailer (ie. from the front bunk to the tow ball). You winch it up tight to the V-notch and then as soon as you let the pressure off the winch the trailer flexes down and the bow moves back from the V-notch. If the winch wire was horizontal, rather than pulling down on the bow 'D' ring I suspect it could help eliminate a major part of this trailer flex issue.

I have just taken some photos of my winch/bow on the trailer. The first photo is with the bow pulled down hard (almost) agains the V-notch. The second is with the tension released off the winch cable and the bow sits back 75mm from the V-notch. The third photo shows the safety chain on and winch cable released of tension - then the bow is about 50mm off the V-notch ie. small amount of tension. I really don't like the way the tension builds up in the trailer arms when the bow is winched down tight against the V-notch - must place some bad shock loads on the trailer and the bow eye.

I have been thinking for some time along the lines of an adjustable headstock, similar to Sumner's, so once the boat is on the trailer in the correct position for balance, and drawbar downforce, then the headstock can be moved up firm against the bow to make the boat more secure on the road. After putting the boat back in the water the headstock would then be moved back to the original position for re-loading. Will be really interested to hear how that mod goes Sumner as I think you are heading in the right direction.
 

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walt

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Jun 1, 2007
3,511
Macgregor 26S Hobie TI Ridgway Colorado
Not a bad idea to follow what Sumner did.

Also, I think this thread has a lot of good suggestions in it...

My boat is 100 miles away so dont have measurements but the picture might be useful (there is an arrow under where I think the roller is).

If I was going to do it over, Id probably try and get the roller "just a little" forward of where I have it although at this point, I dont have much issue with this - dont really have a problem that needs to be solved. I tried the bump one time but that was it.
 

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r.oril

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Oct 29, 2008
586
MacGregor 26D and Catalina 30 26 - 30 Lancaster, CA
Doehunter - I like the "blow the water out of the ballast tank" idea. I have a bow roller, side guides and plenty of power to pull my 26D up any ramp but making the boat 1200 pounds lighter would take the stress out of the bow hook. I still do the Mac Bump just before leaving the parking lot to snug it up to the V.
Thanks.
 

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Sep 26, 2010
808
Macgregor 1993 26S Houston
We are setup to do that, but still haven't. About how long does it take?

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links
I haven't timed it but I think it takes less time to empty than it does to fill.
Generally, when I get to the dock and tie up, I get it out, open the vent and water valves on the tank. I force the end of the hose into the air vent and turn it on. By the time I can get my car and get the trailer in the water, and get the boat on the trailer, it's empty. I leave it running while I pull the boat out of the water. If I stop and get out and look, there won't be any water dumping out of the tank after I'm on dry land.
It's kinda loud if you stay on the boat, but it works real good.
It's become SOP for me as I try to take it easy on my transmission if I can. Older Explorers have a reputation for weak transmissions.
Jim
 
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