Rollers, wobble and glass bottom RIB?

[BoatFisho]

I have a 13' RIB with a glass bottom. In total it weighs about 110kg. The bunk system was worn out and had worn some gel coat prior to me buying it. So now its got rollers. Is it a problem all the weight of the boat on the keel just sits on the middle rollers, or should the wobblie rollers also be supporting the hull? Just a bit worried the wobblie pattern will leave a print in the glass.

 

[64osby]

pictures would really help.

 

[smokeonthewater]

generally I would say yes spread the weight out onto as many rollers as possible but honestly this is a question you should ask the manufacturer of the hull.... "How should this hull best be supported when I'm setting up the trailer?"

A properly set up roller trailer on a small boat like this should only be putting very little weight on each roller..... IE if you have 20 rollers on a 400 lb boat that's 20 lbs per roller.

 

[BoatFisho]

Thanks.

Id love to be able to get pics but just dont have a cam as I broke my phone.

Its got centre rollers and about 8 wobble rollers (the double roller sort). They dont seem to be supporting weight of the boat but I imagine if the boat moves they move with it as they are just touching the boat but I can turn them by hand easily.

 

[GA_Boater]

It sounds like the center rollers should be dropped a bit or the wobbles should be raised a bit.

 

[BoatFisho]

So the wobblers (they are the small ones with the two wobblers close together) should definitely be touching the hull?

Is there a guide, I tried google and got some good tips but nothing definitive on wobbler set up and weight.

Is it as easy as getting under the trailer (safely of course), undoing the bolt and raising each wobbler so it touches the hull? My concern with that is it might be off by default and each wobbler might be crazy different heights.

Thanks for helping.

 

[GA_Boater]

Square the boat on the trailer, level her and raise the wobblers.

 

[BoatFisho]

Good tip as at the moment one side is closer to the mudguard than the other side.

How do I square the boat up, just move the bow around? Raise the wobblers until they are just touching the boat or so they lift the boat?

 

[dingbat]

The keel rollers are to protect and align the keel during loading and off loading. The wobble rolls should be bearing all the weight when loaded

 

[BoatFisho]

i made a mistake its 2 sets of wobblies on each side, the small ones as its a 13' boat. 3 keel rollers. I read most of the weight should be on the keel rollers. Now im confused

 

[dingbat]

i made a mistake its 2 sets of wobblies on each side, the small ones as its a 13' boat. 3 keel rollers. I read most of the weight should be on the keel rollers. Now im confused

My first boat had wobble rollers and one keel roller at the rear of the trailer. The keel roller only touched the bottom loading and unloading.

My last two boats didn't have keel rollers. The entire weight of the boat is supported by the wobble rollers....your mileage may vary

 

[BoatFisho]

Is that a RIB/Inflatable though? I definitely think they need to be taking some weight because the boat rocks a bit on the trailer. Also it lists to the left side and I cant seem to straighten it, yet strangely none of the wobblers are touching hard enough to make it list. Any ideas?

 

[GA_Boater]

Pick the thing up and center it on the keel rollers. You aren't lifting the entire hull weight. Then adjust the wobblers until the boat sits level. Last, raise the wobblers equally until the keel just touches the keel rollers.

 

[BoatFisho]

hull weighs 120kg and the egine about 60kg and its bolt through transom so it aint coming off.

i could get a couple of mates to help lift it. thanks for that

 

[smokeonthewater]

hull weight is irrelevant.... use whatever means are needed to center the boat on the trailer before adjusting.... You may well need to support the entire boat on cribbing, jacks, stands etc and adjust the trailer to it.... As for whether which rollers should support most or all or none of the weight... NONE of us can tell you.... as I stated before contact the manufacturer of the hull and ask where it is best supported....

Anyone who gives you a solid rule such as keel rollers are only to protect but should never support the boat OR keel rollers should fully support the hull and bunks or other rollers should only keep it steady is WRONG.... each boat and trailer setup is different but generally the more square inches supported the better...

Some boats are particularly strong in a certain place or particularly weak in a certain place but MOST are strongest under the stringers and under the keel.... Many have strakes that are a stronger spot in the hull.

MY personal educated guess says strive to equally spread the weight on all rollers with MAYBE a little more on the keel rollers.....

Being able to easily turn the roller is a poor measurement... I had a 5500 lb boat on a full roller trailer and I could easily pull any single roller away from the hull and slip my hand under it.... the only exception was the lone keel roller which was fairly close to the bow... that one has a couple hundred lbs on it and was fixed so it couldn't be pulled away anyhow. Of course "easily" has no specification and what I call easily you may call barely or vice versa...

 

[BoatFisho]

i get what your saying.

end of the day it should be a simple trailer, its only 4 sets of wobbly rollers (the sort that the 2 rollers are close together) and 3 keel rollers. how hard can it be. its a shame there isnt an easy way to test the load on each roller to get it perfect. but ill try but getting it centred, then lift the wobblies just a bit each so they take just a bit of the weight and see if that improves things.

 

[Silvertip]

There are a couple of schools of thought on this topic. First and foremost however, is how many of each roller (keel and wobble) are installed on this trailer determines what the setup should be. Trailer design also dictates what the intended setup should be. Some trailers use fixed keel roller and lots of them. Others use just a couple keel roller and wobblers placed low on the hull serve to carry the weight. The keel is the strongest part of the boat hull -- it is the backbone. Therefore it can support a lot of weight. However, it stands to reason that if you have just one or two keel rollers, that trailer is not set up for keel support. The idea of the wobble roller setup is to provide centering help when loading. They also provide lateral support and some weight support when the boat is fully loaded. Knowing where the boats longitudinal supports are would also aid in setting up the wobblers. You don't want them carrying lots of weight where there is no internal hull support. So the long and short of this is that the keel supports the bulk of the weight but how much of that weight depends greatly on the number of rollers vs the length of the boat. Look at the rollers and if they are highly compressed then this indicates an issue. On the trailer, all keel rollers should be compressed just slightly and evenly. The wobblers can be adjusted against the boat and them moved additionally with the boat off the trailer to provide increased weight bearing if desired.

What I've tried to relate here is that if you look at various trailer manufacturers web sites, they show their various models and what the layout is. You will see there are a variety of designs from the same manufacturer as regards number and placement of wobblers and keel rollers. Setup is very different for the various designs.

 

[BoatFisho]

Its a 14ft designed for this length of boat, it has centerline rollers, 3, it also now has 4 sets of wobblers, 2 on each wide (so 8 actual rollers). I cant remove the boat due to the weight, what I had planned to do was to back off the wobblers, square the hull on the center rollers, then slowly jack each wobble roller so they arent able to be turn by hand but dont totally take the weight off the center rollers. so many ways to setup a trailer and everyone seems in conflict of whats best but speaking to a trailer shop i think i might be on the right path. end of day hull weighs 120kg, engine maybe 60kg. its not a massive heavy boat. i just dont have anywhere to dump the boat off onto.

 

[BoatFisho]

is it ok to jack the rollers up while boats on the trailer?

the rear rollers cant be raised but the rear centre roller can be lowered.

would it make sense to have the rollers sloping the boat gently so it rolls off the trailer easier, ie lower rear roller, slightly higher middle rollers and a higher front centre roller closer to the winch?