Bunked or Rollers??- SIB

LWman · 19 July 2011, 17:49

Im having 0 look finding a suitable & decent condition second hand trailer so iv been looking at new ones and have a couple of questions.
Does a trailer for a 4metre inflatable need to be bunked to support the tubes? Or is rollers just as good? Trailers with rollers seem to be a bit cheaper than bunked new.
Also is it a bad idea to tow a sib with the engine fitted? If so what exactly happens if you do? Does it cause transom damage or does it damage the pin that holds the outboard in up?
Cheers

Max... · 19 July 2011, 18:15

Cannot help with a trailer but found this topic the other day when searching which might help the second question:

http://www.rib.net/forum/f50/outboar...ibs-35542.html

LWman · 19 July 2011, 18:31

Thanks, just had a read through it now. Once i get hold of a trailer ill just give it a go. If it breaks it breaks, but if it doesnt then the goings good

Ill just have to keep an eye on it after each journey.

Markyboyo · 19 July 2011, 22:07

I don't think I have seen a SIB on a roller trailer yet. I would have thought the more focused weight may well damage the Tubes. I'm surprised roller trailers are cheaper than bunk trailers, would have thought the roller would have been more.

captnjack · 19 July 2011, 22:15

Bunks are pretty much required for SIBs. I had my outboard permanently attached to my old Bombard, but consider outboard weight and transom robustness on your particular SIB.

LWman · 20 July 2011, 07:17

I was thinking the rollers would be dearer too, but on small trailers its seems sticking two small rollers at the back rather than having bunks is cheaper. Unless they just realise that bunks are neccessary for inflatable so put their prices up. Looks like ill definately be going for a bunked one then, as i also want to leave the engine attached so want as much support as possible.

jyasaki · 20 July 2011, 14:43

Quote:

Originally Posted by LWman

I was thinking the rollers would be dearer too, but on small trailers its seems sticking two small rollers at the back rather than having bunks is cheaper.

When you're recovering, the back end of the trailer is usually deep enough that the boat doesn't hit there (at least when I recover it is.) Contact is made further up: halfway or even further along towards the front of the trailer. I'd expect that rollers at the back wouldn't do much for you.

jky

LWman · 20 July 2011, 18:19

yeah, i see what you mean. They would be a bit pointless as the boat would be floating above the back of the trailer. Ill definately give rollers a miss and look for a propper inflatable trailer.
Thanks for the replies!

Festinghouse · 20 July 2011, 19:08

Here is a pic of my old sib. I coulnt find a trailer that i thought was suitable of supporting either the boat or engine properly, so i ended up building my own. See how the "spine" of the trailer extends out behind the boat for the skeg to rest on and be strapped down whilst towing. Just in case you were wondering, it is twin axle only for stability not load capacity as i used 8" wheels.

LWman · 20 July 2011, 19:53

That looks a really handy trailer, it looks to do the job perfectly. Iv thought about building one myself with my dad but i just cant imagine it turning out to be any good and i wouldnt want the hassle of it all. Did the extended "spine" help to protect the transom/ motor mount and did you ever have any problems with the engine being fitted while towing? I may consider doing the same thing/something similar as an addition to whatever trailer i pick up, as i also plan to tow with the engine attached.

Festinghouse · 20 July 2011, 20:57

no problems at all, i designed it to do exactly what you want - support the weight of the engine so as not to damage the transom, tubes or mount from the turning motion of the outboard. being able to strap the leg of the outboard to the trailer also meant it held the boat securely whilst being towed. this trailer although i say it myself was a dream to tow - never swayed at all even when i caught myself doing 85 with it! was also light - i could just about pick it up on my own. i have more photos if required.

LWman · 20 July 2011, 21:07

Hmm, your making me want to make my own! If you have an overall pic of the trailer, so i can see the basic layout of how you made it, that would help. Did you weld the majority? I dont have/ know how to use a welder, but i know someone who probably would for a bit of beer money. Self build may possibly still be in the equation as there seems to be very little coming up for sale, although im still waiting for a couple of people to get back to me. I think which ever way i go, ill make sure theres some kind of outboard leg support as to stop it bouncing around and possibly causing damage. It would save time having to lift the outboard out the boot & fit it everytime i use the boat. Which doesnt sound much effort, but when the outboard weighs about 50-60kilo, its a hell of a strain!

kubcat · 20 July 2011, 22:13

If you build your own you may want to use a galvanised square tube unless you can find someone to hot dip galvanise the whole lot when finished. If you use the galvanised tube, make sure you paint over the welds with something like 'Cold Gal'.

Max... · 20 July 2011, 22:28

I'd snap this up super quick:

Snipe SB1-3 boat trailer | eBay

Festinghouse · 21 July 2011, 05:16

built out of 50x50 box for chassis and 50x25 to form the bunks (which were then wrapped in cord carpet). i also used the lowest rated suspension units i could find so there was still some 'give' in them without the trailer bouncing all over the road. people are often temped to put too highly rated suspension units on trailers. i then of course had it hot dipped - not cheap but means it will last forever (almost!). dont be tempted to just paint it as you will regret it, especially if going in the sea. sea water is as effective as acid at killing steel, and you would find a painted trailer suffering after its first seasons use.
i built this 8years ago and it cost just under £500, which was what you could buy a comercial one for, though the difference being that it was made to fit the boat perfectly and was fully welded, as well as supporting the engine and carrying the lighting board!

LWman · 21 July 2011, 07:35

Thats a great trailer that you have made and for £500, it makes it a lot better than a commercial one as its well suited to your boat. I know someone who works with metal who would have gotten it hot dipped, but id imagine the charge would be massive. Thanks for the advise on self build!
Max... Thats a great spot & iv snapped it up! Hopefully ill be going down to collect it on Saturday, just waiting for the contact details from the seller. Nice 3hour drive each way, but you know, itll only have to be done once

.

Max... · 21 July 2011, 07:57

Glad you got it - that was a real bargain and being a proper commercial plated one will hold it's value well.

Poly · 21 July 2011, 09:06

Festinghouse,

I'm no trailer expert but that looks like a long draw bar which will have quite a "twisting moment" on the joint to the front cross member. I know it is only a light boat but it looks to a non-expert like it is crying out for an A-frame at the front - perhaps its because its has 4 wheels that the light weight design looks wrong?

LWman · 21 July 2011, 16:28

Im glad i bought it too, i cant imagine loosing much (if any) money on it if it ever comes to resale. To think i nearly bought a self made one which was pants in comparison for £180... Much rather spend a bit more on the snipe.

Festinghouse · 21 July 2011, 18:06

Quote:

Originally Posted by Polwart

Festinghouse,

I'm no trailer expert but that looks like a long draw bar which will have quite a "twisting moment" on the joint to the front cross member. I know it is only a light boat but it looks to a non-expert like it is crying out for an A-frame at the front - perhaps its because its has 4 wheels that the light weight design looks wrong?

yeah i understand what youre saying, as a twin axle it looks like it should be stronger. but as you say it is a very light boat and not a huge amount of weight on the nose so was never a problem when loaded. the only time i noticed any flex in the drawbar was when it was being towed empty and i could feel it wobble as it bounced over any bumps in the road. the only real flaw in my design that i saw was the height of the bunks - if they were lower then it would have been easier to launch on a shallow sloping beach.