26 M falls off trailer

[pokerrick1]

**let's stick to loads on trailers so we don't have to argue about terminal velocity with wind resistance and objects in a vacuum and such, okay?

OK with me I don't know what you're talking about anyway

Rick

[Québec 1]

Me too! but I gather it has something to do about how conclusions based on the empirical method vs the scientific method should be viewed. Sort of like the creationists and the Darwinians.....I also sort of gathered I was more creationist . Hope this helps Rick.
Bertrand

[pokerrick1]

HUH

Rick

[Boblee]

Sorry cannot see any positives to not pulling your boat up to the vee any slackness there allows your boat to move under extremes, both up and down and forward and back.
The winch strap is mainly to pull the boat into position and hold it there but under no circumstances should it be relied on, a chain to the bow eye should be in place to secure it in case of any mishap, but a good strap right across the stern behind the cabin should be a must.
When I first trailered my boat the son in law was coming up behind me and pulled me over as the boat was bouncing 6" on every bump, the rear strap fixed that and have never had a problem with it expanding etc.
Our boat has done many many thousands of miles (on nightmare roads) and never had a problem with damage to the boat during travel but did have a rim come loose which destroyed the hub etc but no problem with the boat moving.
We may have rough roads here but by driving accordingly IMHO there is far less danger than being on a freeway with an unsafely loaded boat going way too fast.
I check the load regularly or when I pull up for whatever reason but we still get caught, eg visually checked wheels only 40k's prior to rim disintergrating and it had done over 2000k's in the week prior and had been tightened regularly but not that morning, can only presume moving off the rough narrow road to avoid a fast moving road train had loosened the nuts but should have tested with wrench again prior to departure that morning.

[Québec 1]

I, as thousands of other Mac owners also have traveled thousands of miles with no problem, no rim problems , no problems with our bearing buddies, no problem with our cargo tires, no problems with our trailer brakes and no extra strap on the aft end. Just saying if it's so catastrophically dangerous how come guys like us are not in any way....showing up in catastrophic situations more often then you guys? Could it be that smoking Lucky Strikes makes a difference?
Q1

[vizwhiz]

OK with me I don't know what you're talking about anyway

Rick

Always a funny...

I, as thousands of other Mac owners also have traveled thousands of miles with no problem, no rim problems , no problems with our bearing buddies, no problem with our cargo tires, no problems with our trailer brakes and no extra strap on the aft end. Just saying if it's so catastrophically dangerous how come guys like us are not in any way....showing up in catastrophic situations more often then you guys? Could it be that smoking Lucky Strikes makes a difference?
Q1

I was in no way implying that you couldn't travel safely with your loaded boat on the trailer, or that you and others HADN'T already done so for many many miles...although the Lucky Strike's MAY have had something to do with this... I was merely pointing out that there are true physics behind the reasoning used to strap the load to the trailer...and more than what I posted, although the relative movement potential between the two is the biggest reason. Friction, which is what keeps the boat from sliding on the bunks, is based on the weight of the object (and interestingly, not the surface area) and how "slippery" the two surfaces are. As you hit bumps, the load becomes weightless relative to the trailer, and you have essentially no friction...maybe for only a fraction of a second...but if you're hitting your brakes and/or turning sharply to avoid something in the road...it all adds up.

I suspect, and correct me if I'm wrong, that a person such as yourself who is relatively detail-oriented and particular, likely drives as though you have a demitasse in your hand and does not wish to spill and soil his sailing shorts. In English, I'm saying you're probably a pretty conscientious and careful driver, you're a defensive and safe driver, and don't push the boat/trailer hard nor drive hard on rough roads.

If we were talking hypothetical, that would be one thing...but the Mac on the interstate is...real. And no, it won't happen every time you go out...but in my book, once (by accident of course!) is still one time too many. My boat will be strapped to the trailer.

[Divecoz]

Ahhhh most of US dont drive like idiots??? I most often Chain my boat at the bow.. Why? Because often its the law , as is, having a spare tire for the trailer!!! Most often I use 2 ratchet straps at the transom ( Rear Mounted Cleats on the M ), to the trailer.. Why? Often its the law.. A single strap across the boat side to side ( as suggested here ) Might ..stop it from coming off the trailer... if its like one of my 4" wide Industrial straps and it may even stop or reduce side to side shifting.. However 2, even light weight ratchet straps, one on each side do the trick..Chain Lock 2 cheap ratchet straps $20 and No Issues.. Legal or otherwise

I, as thousands of other Mac owners also have traveled thousands of miles with no problem, no rim problems , no problems with our bearing buddies, no problem with our cargo tires, no problems with our trailer brakes and no extra strap on the aft end. Just saying if it's so catastrophically dangerous how come guys like us are not in any way....showing up in catastrophic situations more often then you guys? Could it be that smoking Lucky Strikes makes a difference?
Q1

[Boblee]

Yeah at the speeds I drive I daresay I could get away with nothing but the winch strap, PROVIDING I stayed on reasonable roads (not many here even freeways) and kept the odds down by restricting distances.
Last years trip alone was over 7,000 k's? and the majority of those roads were goat tracks even the Stuart Highway in places where the boat would have been airborne at 80k's if not strapped down, granted it may not have come off the trailer but repeated landings on the berths (3) would not be better than none.
The incident I mentioned in a previous post where the boat was jumping 6"was on a dirt driveway at max 15kph can only imagine what would happen at a bad grid at highway speeds, perhaps it could be interesting to drive behind an unstrapped boat over some corrugations or hit the brakes simulating an emergency situation when the boat is not hard into the vee berth which incidently destroyed my original winch post assembly just doing the mac bump when the boat hit it with speed when slippery from fresh water slime.
If someone wants to drive around with the boat only secured by the winch strap go for it but I do think it's unwise to advise others to who may not have the same conditions including driving skills.
The boat in the op with the bow hook broken or pulled out and the boat sliding up the road would be a very minor end to what could have been.
Anybody feeling adventurous try leaving 4-6" of gap and then hit the brakes to move the boat forward and then take off forward hard, sure the strap will hold when new and especially if you have been a while in salt water but if slippery from freshwater slime it may be a different story.
To give an idea of different conditions I tried everything to do the mac bump after 6 weeks in tropical water even going down the ramp and slamming the brakes on and it still refused to budge but after going from there to a freshwater run of a week a slight tap on the brakes bent the winch post assembly forward 6" as mentioned above but have had a few emergency stopping situations and no problems with the boat up againt the vee .

[seahouse]

My own personal schema on this (for decades) has been to tighten the bow eye down with the winch, and tighten the tansom hooks (or hold-down straps) when trailering, and keep them loosened off at all other times, ie. during storage.

Fibre-reinforced plastic (FRP)( in our Macs it’s glass fibres in a polyester matrix) will undergo irreversible plastic deformation if a load is applied to it over time. The very name “plastic” implies by definition that it will yield and deform under load. Loosening the winch and hold-downs removes loading from the boat structure to that provided by gravity.

It would be reasonable to expect that the factory trailer supports the hull in the locations that minimize loading and strain. I have seen FRP hulls deformed and ruined by storage on an ill-fitted trailer.

I don’t think that thermal expansion and contraction can have much negative effect on the hull when secured to the trailer, because the trailer and straps themselves are expanding and contracting at the same time, plus, they are not solid and ungiving, but flexible.

True, the coefficient of thermal expansion may be somewhat different for the steel/ aluminum of the trailer and the other materials, but by comparison there is a far greater strain from temperature changes within the FRPitself.

[ The plastic matrix expands and contracts (IIRC) 10-15X more than the glass reinforcing fibres that it contains, and yet this causes little ill-effect to the integrity of the material. (BTW – this is one reason fibreglass windows have such and advantage – they expand and contract at nearly the same rate as the glass in the window does).]

I would also think that the bow eye should be pulled up to engage in the rubber “V” because it improves structural integrity while tailoring, something which I would think you would want to maximize if you had the choice. When secured this way the bow of the boat stabilizes the trailer tongue against both twist and flexing in the vertical plane.

To demonstrate this for yourself, use the trailer jack with, and then without the “V” engaged, and you will see the stability against twist the engagement provides. The boat is a stressed part of the unit structure of the trailer/ boat combination while on the road. Similarly, the rear tie-downs provide some integrity by transferring the ridgidity of the hull to the trailer.

Not tying down to the trailer to relieve stress from bumps??? HUH??? I can see no basis in practical mechanics or physics there in the real world.

-B.

[mastreb]

All considerably true about strapping a boat down to the trailer and then storing--the plastic will give on the trailer blocks before the straps do. Nylon docklines strapped round the trailer from the stern cleats with a trucker's hitch keep the boat attached to the trailer and are more elastic than straps.

[Boblee]

Mastreb you are probably right about the nylon ropes but would suggest that any tie downs are just that tie downs (to stop bounce and movement) and not pull downs, even a truckers hitch pulled down can put undue stress on the hull probably worse than overloading.
I got my alum dinghy cheap due to a trucky buying it new and then pulling it down to the point of splitting the hull when loaded and trailering but it's never been a problem in the 10 years since just tied down and it has been round aust twice with a LOT of wriggles in between over THE roughest roads here including Gibb River and Cape York roads.

[korn_kid_12]

I used to tow my m25 with a jeep grand cherokee overland edition. First let me start by saying the jeep my makes more HP and torque then my truck does now. Which made for a much nicer drive. However I did purchase a 1/2 ton 4 door to take advantage of the much longer wheelbase. With the jeep my m25 would rag ridiculously when a box truck think ups or larger passed regardless of how it was loaded. Loading the bow heavily and removing the outboard helped somewhat. Towing between 50 and 55 also helped. It was a white knuckle affair regardless till I added sway control and purchased the truck. That made the world of difference sailing became fun again, and was not completely canceled out by the miserable drive. Soon after I towed it 8 hours at 75mph plus and left it with its new owner. My 26 doesn't have sway control and I do not plan on adding it. Neither trailer have brakes of any kind. Some nice electric disks would be nice though.