Converting a small luggage trailer to fit SIB

[joeletaxi]

Hi all,

I have acquired an 11ft sib with 3hp engine quite a while ago and unfortunately, never had much time to use it as it was in a storage place for a while we were building our place

Now we have a proper garage and I bought a compact trailer (5x3) with an enclosed roof.


The trailer being small (I am driving a corolla) and the basket being a bit to narrow but full metal, I am planning to add a roof rack with a bar of about 5.5ft, then add two wooden planks to secure the tubes (width of boat is about 5.2ft)
Another Idea would be to flip the boat upside down and rest the aluminium board against the metal basket and secure it.

If anyone has any better idea I would love to hear from you!

I have only basic knowledge of trailer and not sure if putting a boat bigger than the trailer would be an issue as well. The trailer is about 9.8ft long including the tongue and the boat is 11ft. so I would have to have the boat hang out slightly on the back (about 1.3ft)

Hoping to have it operational for an outing asap!

[ShinyShoe]

Is that 9.8ft long from back of the box to the hitch?
You will need to mount it far enough back that the boat doesn't touch the car remembering as it trails round corners the space reduces.

I suspect the balance will be wrong and you'll end up with a "negative weight" on the tow ball. That might make some interesting towing characteristics

Not sure on AUS law on overhangs on trailers... 1.3ft in the UK would be OK.

[breezeblock]

Originally Posted by ShinyShoe

Is that 9.8ft long from back of the box to the hitch?
You will need to mount it far enough back that the boat doesn't touch the car remembering as it trails round corners the space reduces.

I suspect the balance will be wrong and you'll end up with a "negative weight" on the tow ball. That might make some interesting towing characteristics

Not sure on AUS law on overhangs on trailers... 1.3ft in the UK would be OK.

its an 11ft sib I am sure it could be quite easily counteracted my adding some bricks up the front I don't think there would be much of an issue with weight

[joeletaxi]

Is that 9.8ft long from back of the box to the hitch?
You will need to mount it far enough back that the boat doesn't touch the car remembering as it trails round corners the space reduces.

I suspect the balance will be wrong and you'll end up with a "negative weight" on the tow ball. That might make some interesting towing characteristics

Not sure on AUS law on overhangs on trailers... 1.3ft in the UK would be OK.

Originally Posted by breezeblock

its an 11ft sib I am sure it could be quite easily counteracted my adding some bricks up the front I don't think there would be much of an issue with weight

Thanks for the tip for the front, something to keep in mind

I'd be interested to learn more about the negative weight. Does it mean that the front has to be heavier than the back? How about the middle area?

I saw a youtube video not too long ago about how a vehicle can lose control if the weight on the back is more than the front.

To counteract this I will make an extra storage box on the A-Frame (tongue). Where I would add one propane gas bottle and 1 big esky or storage box containing all the heavier items. If the build allows, I would also look into putting the engine at the front mounted on some wooden block.

Would it be enough?

[ShinyShoe]

For bigger trailers you'd expect to have 50-75kg pressing down on the towbar. Basically if you sit it level and put a wooden pole between the tow hitch and the ground and then put a set of bathroom scales between the wood and the ground it should read 50-75kg. For a small trailer like that it is probably not going to read 75kg. But "in theory" if it isn't readying anything because the tow hitch lifts in the air then your trailer is trying to lift the rear wheels of the car off the ground... I suspect if that is -5kg it probably makes no difference if its -50kg - maybe it does affect traction etc??

I suspect it will bounce about a heck of a lot if nothing else.

Remember you are dealing with levers - so effects are multiplied as they move in distance away from the axle.

[joeletaxi]

Originally Posted by ShinyShoe

For bigger trailers you'd expect to have 50-75kg pressing down on the towbar. Basically if you sit it level and put a wooden pole between the tow hitch and the ground and then put a set of bathroom scales between the wood and the ground it should read 50-75kg. For a small trailer like that it is probably not going to read 75kg. But "in theory" if it isn't readying anything because the tow hitch lifts in the air then your trailer is trying to lift the rear wheels of the car off the ground... I suspect if that is -5kg it probably makes no difference if its -50kg - maybe it does affect traction etc??

I suspect it will bounce about a heck of a lot if nothing else.

Remember you are dealing with levers - so effects are multiplied as they move in distance away from the axle.

I see, I will have to look into that.

In the meanwhile, I used some 3d object from Sketchup and resized them they should be the roughtly the right dimensions. I will post a picture of the real setup once they install the towbar on my toyota (used a mazda 323 as they didn't have any 3d corolla hatch).

Which setup would be the most efficient?




how to upload a picture on the internet

[Poly]

None of those! You don't want the engine flapping about on the transom like that unsupported. I wonder if you might also suffer with the bow trying to lift (and bend the boat at the thwart) at any speed.

The exact fore-aft position will depend on trial and error to get the balance right so it is both easy to load/unload and has enough nose weight when towing. If you are using it single handed then a roller on the back of the trailer might help man handle it.

Are the boat supports running forward and back or across the width?

Ps. Nice white oilies you've got on there ;-) do you have a matching jacket?

[ShinyShoe]

I'd be curious if engine over the front was better balanced and easier to add a support underneath. BUT wont be as easy to load.

[Andy JC]

Surely the engine will be best removed and stored inside the trailer, forward of the axle to increase nose weight slightly.

[joeletaxi]

Originally Posted by Poly

None of those! You don't want the engine flapping about on the transom like that unsupported. I wonder if you might also suffer with the bow trying to lift (and bend the boat at the thwart) at any speed.

The exact fore-aft position will depend on trial and error to get the balance right so it is both easy to load/unload and has enough nose weight when towing. If you are using it single handed then a roller on the back of the trailer might help man handle it.

Are the boat supports running forward and back or across the width?

Ps. Nice white oilies you've got on there ;-) do you have a matching jacket?

Yes sorry, it is just a 3d representation, as I said previously the outboard will be mounted in front of the trailer, I didn't remove it on the sketch.

I do worry about bow lifting too, I saw on google they attach the bow ring to the front of the car and in this case the front of the trailer.

I do also believe it would be best to flip the boat around but I am concerned the aluminum floor might fall. I might give a try first to see how it goes I guess.

Most of the weight ball scale I saw were very expensive or only starting at 100kg, I will either have to diy or use a portable scale as the trailer will be around 400kg (250kg for the trailer + 70kg for the boat + 80kg of other stuffs)

Also there will be a roof rack with long bars on top and wood support going accross the length to support the tubes

[Stigomery]

I might have missed something, but why don't you put the engine in the trailer and the boat on the roof of the car...? SIBs are relatively easy to stow upside down on the roof of a car (unless huge/ally floor'd) and it will be much more safe/stable/forgiving... I frequently throw the Honwave T-38 on the roof of the car and/or SWB Landy, both can be done single handed with a bit of shoving and manoeuvring and I'll happily drive at up to 60mph with it on the roof of the car.

I would not tow a fully inflated SIB on a trailer as you have in any of the images except at sub-20 mph speeds... looks very unstable

[joeletaxi]

Originally Posted by Stigomery

I might have missed something, but why don't you put the engine in the trailer and the boat on the roof of the car...? SIBs are relatively easy to stow upside down on the roof of a car (unless huge/ally floor'd) and it will be much more safe/stable/forgiving... I frequently throw the Honwave T-38 on the roof of the car and/or SWB Landy, both can be done single handed with a bit of shoving and manoeuvring and I'll happily drive at up to 60mph with it on the roof of the car.

I would not tow a fully inflated SIB on a trailer as you have in any of the images except at sub-20 mph speeds... looks very unstable

I thought that the boat being behind the car would be sort of protected against the wind/drag.

The engine will be mounted or stored at the front on the tongue/a-frame of the trailer so I can get more storage space for other things in the trailer. It's only a 5x3 trailer so there is not that much boot space.

I had a look at your setup. It looks great but my car is quite small and the boat with the aluminum frame will be 65kg a tad over the car limit, I wouldn't want to risk the car roof bending.

How about putting the boat upside down on the trailer? Would it be more stable?

Just got the towbar fitted will post some pictures soon

[joeletaxi]

[jeffstevens763@g]

we travel all over the country with our 3.1 m sib on two bars the rear one has a pipe over it and acts like a roller for putting the boat on. so it's 4 uprights two bars across and two stabilizers between the uprights on the sides, engine in the van or in the trailer in your case the boat weight doesn't affect the the tow bar weight the kit in the trailer sorts that out just load it properly. if it's pumped up properly it will be ok you need the bow line securing to stop bow lift. if you have the boat upside down it might get caught on the car when you turn. let your keel down to if the boat is sat on it makes it more level

[joeletaxi]

Originally Posted by jeffstevens763@g

we travel all over the country with our 3.1 m sib on two bars the rear one has a pipe over it and acts like a roller for putting the boat on. so it's 4 uprights two bars across and two stabilizers between the uprights on the sides, engine in the van or in the trailer in your case the boat weight doesn't affect the the tow bar weight the kit in the trailer sorts that out just load it properly. if it's pumped up properly it will be ok you need the bow line securing to stop bow lift. if you have the boat upside down it might get caught on the car when you turn. let your keel down to if the boat is sat on it makes it more level

Do you have a photo of the setup? I would love to see it

[jeffstevens763@g]

https://www.google.co.uk/search?q=mo...YPjtmR0OilNaM:

Very similar to this

[joeletaxi]

Thanks ! Gave me some ideas (albeit an expensive one )

I am thinking of getting rid of the flawed roof basket and weld a new one that will incorporate all the ideas I have been having ( and at the same time pick up up yet a new hobby).

That's a prototype so far. What do you think?

[jeffstevens763@g]

looks good