Building a super new boat trailer, but on the cheap!

[Markyboyo]

I've always thought my 1300GW trailer with 1000kg capacity was a little under engineered and it is defo less rigid than I would like. It only uses 2 80*40*3 chassis rails with no additional reinforcement. Its from one of the respected manufacturers who is well regarded on here and elsewhere but I am now wondering if it is up to the job.........

I gotta admit that all the other 1300 kg trailers I have seen have top and bottom rails on each side, not just one.

[Anchorhandler]

Originally Posted by HughN

They were a "finger in the air", "not to scale", "the value of your investment can go down as well as up" type bodge I hasten to add!

Maybe, but the calculations i carried out were'nt.....the point was not to focus on the exact figures but to show the higher bending stress at the end of the rails.

Originally Posted by Markyboyo

I've always thought my 1300GW trailer with 1000kg capacity was a little under engineered and it is defo less rigid than I would like. It only uses 2 80*40*3 chassis rails with no additional reinforcement. Its from one of the respected manufacturers who is well regarded on here and elsewhere but I am now wondering if it is up to the job.........

I gotta admit that all the other 1300 kg trailers I have seen have top and bottom rails on each side, not just one.

I'm sure it will be fine...the case discussed in this thread involves only one particular home built trailer and dont forget, any trailer can be overloaded if it is not set-up correctly.

You have to take into account also that i never included a safety factor when working out the loadings ie: i never increased the loadings by a set percentage to take into account potential overloading, shock loading and wear on the chassis itself. By the same token though i never took into account the heavy angle bar u-bolted to the chassis rails just above the axle. As i mentioned previously, this angle bar will have a positive effect on the load handling ability of the trailer in question.

If i had to certify Jeepster's trailer i would agree that 800kg's is probably a sensible load limit as quoted by Indespension (not the 1300kgs he initially hoped for and subject of course to all components being welded together correctly).

As to why your trailer has a higher GW, this could be down to many factors like quality of steel used, set-up of the axle/rail, whether its a bunk trailer/swingbeam trailer etc...

Simon

[jeepster]

Originally Posted by Anchorhandler

Yes actually, i do call myself a Chief Engineer....

The load is equally distibuted at both ends because, as i mentioned, i'm only intrested in calculating the stress in the side rails at the area they connect with the axle. This is the most critical part of any trailer.

Re-read post number 86 and you will see that i mention a 150mm area where the rails connect to the axle....this is represented in the drawings by the two black triangles....funny enough, spaced 150mm apart.


If you also look at the calculations i have given you in the same post (200 X2)+(210 X2)=820Kgs, i thought it would have been obvious that the calculation was for one rail only considering i'm multiplying the loadings by two to account for the whole trailer.

I gave you an estimated maximum loading for your design of trailer at 820Kgs....based on my calculations. Have you actually checked what an Indespension 1100kg trailer is rated to carry? Funny enough i just have a few minutes ago... 800Kg max!
So not only are my calculations correct, it means that this fantastic trailer you've constructed is very nearly on the absolute limit for what your boat weighs....better not think of uprating that engine for a while then!

I also suggested you move the rear swingbeam forward to make it safer.....Look at the bending diagram and shear force diagram HughH has kindly uploaded and pay rarticular attention to the high bending/Shear force at the rear of your trailer (P.S. Thanks for taking the time to do this Hugh).

Finally, look at the calculations YOU have used and exoplain to me what is wrong here....Where did you get a 440 odd tonne load from?

Yes, thanks HughH. But what 440 tonne load??? Look at it again. The units are in Newtons (hence the N in brackets)...4482.2N is 457kg.

Originally Posted by Anchorhandler

and, as Hugh also questions....where has the uniform loading come from??

But the loading is not uniform!...Its heavier over the rear swingbeam than the front swingbeam...As my model clearly shows.
In an earlier post I have even given you a calculated split in the loading of about 68.6% over the rear swingbeam and about 31.4% over the front swingbeam.

Originally Posted by Anchorhandler

Both myself and others on here have genuinly tried to give you sound advise but you have chosen to refute it each and every time....

I dont remember there being much sound advice here...There have been an awfull lot of patronising and condescending comments aimed my way though...But of course most of them can probably be put down to the fact I dont have a RIB.

[dally]

"But of course most of them can probably be put down to the fact I dont have a RIB. "

or indeed a brain. Tis a good job you have something fit only for a canal where a duck's wake is as much of a sea as you will need to cope with, you would be surely dangerous in anything faster and at sea. I just hope I am never anywhere in the vicinity of the outfit on the road especially with my family in the car. If there was ever a case to support those who advocate compulsory MoTs on trailers this is it. And for a professional lorry driver (albeit unemployed for some reason) to have been working on such wildly inaccurate weight estimates is inexcusable.
On the other hand perhaps just a pillock with nowt else to fill his time but wind folk up.
Good rant that, most enjoyable.

[Anchorhandler]

Originally Posted by jeepster

Yes, thanks HughH. But what 440 tonne load??? Look at it again. The units are in Newtons (hence the N in brackets)...4482.2N is 457kg.
But 44822.2N certainly isnt..... and your telling me to look again? Care to reconsider the results of your calculations now? (Oh, and check out the dimensions you have inputed for the rectangular section while your there.)


But of course most of them can probably be put down to the fact I dont have a RIB.

No, I think you will find that its probably because you only very recently joined this forum but promptly decided to teach some very experienced people all about how to load a trailer, how to lighten steel members and RSJ's, all about the mechanics and stress distribution in loaded beams and all along have refused to accept that you have been wrong in pretty much everything you have stated since you joined.


Who the f**k builds a braked trailer for a boat he doesnt even know the weight of anyway? Your no doubt going to keep towing it with your current tow vehicle as well i suspect.


Perhaps you may have better luck on one of the other dozen or so forums you have uploaded the same pictures and description to?

Speaking of forums....


17 foot boat across the channel...Possible? - Yachting and Boating World Forums


Did make me laugh...

Simon

[gasman]

Originally Posted by dally

"But of course most of them can probably be put down to the fact I dont have a RIB. "

or indeed a brain. Tis a good job you have something fit only for a canal where a duck's wake is as much of a sea as you will need to cope with, you would be surely dangerous in anything faster and at sea. I just hope I am never anywhere in the vicinity of the outfit on the road especially with my family in the car. If there was ever a case to support those who advocate compulsory MoTs on trailers this is it. And for a professional lorry driver (albeit unemployed for some reason) to have been working on such wildly inaccurate weight estimates is inexcusable.
On the other hand perhaps just a pillock with nowt else to fill his time but wind folk up.
Good rant that, most enjoyable.

Love it. Jeepster has supplied the best Sh-te since SR4

[tonto]

Originally Posted by gasman

Love it. Jeepster has supplied the best Sh-te since SR4

I am sure he is SR4!

[Pikey Dave]

Originally Posted by tonto

I am sure he is SR4!

11th post on page 1





As Willk said yonks ago
\l/ \l/ \l/ \l/ \l/ \l/ \l/ \l/

[BogMonster]

Originally Posted by ShinyShoe

If you want to save weight on the trailer just drop the lengthwise bars alltogether. Balance the boat very carefully on the axle and pull it by the painter. I'm not a structural engineer or anything but I'm sure you'll have reduced the trailer weight by the maximum amount possible and it'll stop these guys all shouting at you about the dimensions of the box section.

[Boats&Outboards]

Have you been drilling holes before Jeepster ?

Peter @ Boatsandoutboards4sale ~ askboatsandoutboards4sale@sky.com ~ 07930 421007

[A1an]

I bet they are strong!

[Jonny2488]

I have to say guys, this is one of the most entertaining threads I've ever read on rib.net!!

Jeepster, I think you need to have a good hard look at yourself in the cold light of day. Have a read back over this entire thread with an as unbiased view as possible.....I think you might be embarrassed at quite how awful a picture of yourself you've painted here.

At the end of the day, look at the photos you posted yourself. The longitudinals are clearly under stress! You might expect that kind of deflection momentarily over speed bumps or pot holes.....but definitely not while stationary!! Bottom line is that that trailer is properly under engineered and as a result properly unsafe!! I don't expect any of this to sink in as none of the previous 131 posts seem to have done, but I just hope this thing never makes it to the roads!

Could you do us all a favour: just drop a thread on here before you leave the house with your trailer in tow so we have a chance to get off the roads!!

P.s - unemployed for over a year you say? Shouldn't you spend less time bodging trailers and more time trying to find a feckin' job!!

[tonymac]

Guys , guys, guys ... this fella is priceless. Go read some of the stuff he says about his plan to cross the Channel! (http://www.ybw.com/forums/showthread...light=jeepster) According to him you don't need a radio, plotter, charts, flares or radar reflector. AND he will make it with a 9.9hp engine in 2.5 hours on 5 gall of petrol!

Jeepster, just take the damn thing out on the road. Make sure you have plenty of insurance though. Cause if your boat hits me falling off that trailer I'm going to sue you for so much it might buy me a new Redbay!

Oh and by the way, the main proof of evidence against you will be this thread. You have been warned till it is coming out of your ears and you don't give a toss. So go ahead. I hope some poor person isn't killed but I sure hope they take you to court.

Besides all this I think this guy is a wind-up merchant. I mean can you be that stupid? Seriously??

[Jonny2488]

HAHAHAHAHAHAHA this is brilliant! In the thread that tonymac posted the link for above, when contemplating crossing the channel in Jeepster, one poster replies with:

"The safest way would be put the boat on a trailer, all jump in the tow car and and go on the ferry." - NO F*****G WAY!!

Seriously mate, take a look at yourself. I wasn't just jumping on the band wagon with the comments in my earlier post, there are some seriously experienced posters on rib.net and their advice is reliable and well meant.

#likealambtotheslaughter.

[Andy B]

Old jeepster has certaily been through some trailers in it's time!
this must be the yank one refurred to in the OP.
would have been quicker and cheeper to buy a better tow car me thinks...

[jeepster]

Originally Posted by Jonny2488

I have to say guys, this is one of the most entertaining threads I've ever read on rib.net!!

Then you really should get out more!

Originally Posted by Jonny2488

Jeepster, I think you need to have a good hard look at yourself in the cold light of day. Have a read back over this entire thread with an as unbiased view as possible.....I think you might be embarrassed at quite how awful a picture of yourself you've painted here.!!

Perhaps YOU should go back and read all the patronising and insulting comments thrown my way, even AFTER I proved Simon did not have a clue what he was talking about, because his MITcalc model was all wrong and did not reflect the actual loadings on my trailer, as my MITcalc model did.

Originally Posted by Jonny2488

At the end of the day, look at the photos you posted yourself. The longitudinals are clearly under stress! You might expect that kind of deflection momentarily over speed bumps or pot holes.....but definitely not while stationary!! Bottom line is that that trailer is properly under engineered and as a result properly unsafe!!

Then by all means let Indespension Trailers know of your concerns so they can issue a general recall of every Roller Coaster 1.3HE trailer they have ever sold!
My trailer uses exectly the same materials and has the same capacity as the Indespension Roller Coaster 1.3HE...If its good enough for them, its good enough for me!
ROLLER COASTER 1.3HE | Roller Coaster | Marine | Leisure | Trailer Range | Indespension

Originally Posted by Jonny2488

I don't expect any of this to sink in as none of the previous 131 posts seem to have done, but I just hope this thing never makes it to the roads!

On no!...Hundreds of Roller coaster 1.3HE trailers are already on the road!! ...AAAAAAAARRRGGGH!!!!

[jeepster]

Originally Posted by tonymac

Guys , guys, guys ... this fella is priceless. Go read some of the stuff he says about his plan to cross the Channel! (17 foot boat across the channel...Possible? - Yachting and Boating World Forums) According to him you don't need a radio, plotter, charts, flares or radar reflector. AND he will make it with a 9.9hp engine in 2.5 hours on 5 gall of petrol!

Jeepster, just take the damn thing out on the road. Make sure you have plenty of insurance though. Cause if your boat hits me falling off that trailer I'm going to sue you for so much it might buy me a new Redbay!

Oh and by the way, the main proof of evidence against you will be this thread. You have been warned till it is coming out of your ears and you don't give a toss. So go ahead. I hope some poor person isn't killed but I sure hope they take you to court.

Besides all this I think this guy is a wind-up merchant. I mean can you be that stupid? Seriously??

No, because I'm not Irish!

[Nos4r2]

I know someone like Jeepster. He absolutely WON'T be wrong, no matter how much of a tit he makes of himself.

This is his current project. I've tried to tell him, but he's convinced it'll be a viable tender.

Reckon it'd make it to France?

[jeepster]

Originally Posted by tonymac

Guys , guys, guys ... this fella is priceless. Go read some of the stuff he says about his plan to cross the Channel! (17 foot boat across the channel...Possible? - Yachting and Boating World Forums) According to him you don't need a radio, plotter, charts, flares or radar reflector. AND he will make it with a 9.9hp engine in 2.5 hours on 5 gall of petrol!

You obviously have problems with reading things in context, or perhaps reading, period?...I never said I would make it with a 9.9hp, I was simply asking whether anyone thought it was possible to do it with a 9.9hp...And you will note that most of those that initially thought it was a ludicrous idea changed their mind after I showed them a picture of jeepster and they realised it wasn't some tiny rowing boat!.

[Downhilldai]

Back to the trailer, your design is more akin to the Indespension RC3:

ROLLER COASTER 3 | Roller Coaster | Marine | Leisure | Trailer Range | Indespension

Indespension state this has an unladen weight of 325kg, so I expect yours would weigh roughly the same, perhaps more, as it appears to have more steelwork at the front end. Have you weighed your trailer without the boat on it?