damage from keel roller brackets

[tcurtsinger]

Just got this boat cheap, 16' Ebbtide v-hull runabout. The trailer has 4 keel rollers that support the boat with short bunks on sides to stabilize it. The previous owner kept the boat in the water most of the time, but there is damage that looks like the keel roller brackets digging into the gelcoat when it was loaded. The rear roller is 12", the rest are 4". I'm afraid to repair the damage without adressing the problem first since I will be loading/unloading with every use. What is the best way to prevent that type of damage? I was looking at upgrading some or all of the rollers to 12" and maybe adding roller guides, or both. Any advise is welcome.

 

[Bob's Garage]

Re: damage from keel roller brackets

The keel rollers should not be supporting the boat. They are there to keep the keel from being damaged by the trailer cross braces and guide the boat onto the trailer.

Readjust the rollers so they barely touch the keel, letting the bunks support the boat.

The damage is caused by the boat wandering off the center when loading and catching one of the support brackets. More directional support from the bunks should help alleviate this problem. The trailer may be being backed in to far which tends to let the boat wander around. If more bunk is exposed, they will have move control/effect on the boat, forcing it to center on the trailer.

It is possible that your boat could benefit from center bunks that help position the boat onto the trailer. If so they are not difficult to install.

 

[Bondo]

Re: damage from keel roller brackets

The trailer has 4 keel rollers that support the boat with short bunks on sides to stabilize it.

Ayuh,... Ya got that Backwards....
It should be supported by the Bunks...
The rollers should do little, other than guiding the hull into place...

 

[bonz_d]

Re: damage from keel roller brackets

16' v-hull runabout. The trailer has 4 keel rollers that support the boat with short bunks on sides to stabilize it.

I get a laugh every time I see this and the posts that follow stating that the bunks should support all or most of the weight.

Someone please explain how one is supposed to support all or most of the weight of a boat when the trailer has SHORT BUNKS which only go as far as the second roller from the transom or only 25-30% of the lenght of the boat and more than half of the boat is sitting on rollers.

I do not understand how this can physically be done.

 

[Bondo]

Re: damage from keel roller brackets

I do not understand how this can physically be done.

Ayuh,.... Where,..?? Exactly is the Center of Gravity on a Boat,..??

You'll find it's about Exactly where the Bunks are....

 

[superbenk]

Re: damage from keel roller brackets

If the current bunks aren't doing the job, maybe they need to be replaced with longer ones. Also, you might consider upgrading from 4" rollers to 8" rollers to provide some more surface area for the keel to hit.

I also definitely agree with the comment about not backing the trailer in so far.

Finally, you might want to consider adding guide-ons to the sides of the trailer. I made my own from PVC pipe:

But you can buy some nicer ones that are actually like bunks mounted on their sides which provide more strength & surface area for guiding the boat on.

 

[bonz_d]

Re: damage from keel roller brackets

So you are saying that the CG on all or most boats is 75-80% to the stern?

I find that very hard to believe. Believe me I understand CG as I used to load cargo planes in the Air Force!

 

[superbenk]

Re: damage from keel roller brackets

So you are saying that the CG on all or most boats is 75-80% to the stern?

I find that very hard to believe. Believe me I understand CG as I used to load cargo planes in the Air Force!

Think about where the heaviest item on your boat sits, the engine, on the stern. Then there's the outdrive which sits behind the stern. Then there's the battery(ies) which sits at the stern & the gas tank (in most boats) sits just in front of the engine (ie, towards the stern, maybe midship).

So CG might not be on the stern, but it's aft of midship.

 

[bonz_d]

Re: damage from keel roller brackets

the engine, on the stern. Then there's the outdrive which sits behind the stern. Then there's the battery(ies) which sits at the stern & the gas tank (in most boats) sits just in front of the engine (ie, towards the stern, maybe midship).

So CG might not be on the stern, but it's aft of midship.

I agree with ALL that on I/O's, though not every boat is an I/O. Will also agree that on every boat the CG is aft of midship but the question still remains how far aft? 50% aft, 75% aft? 90% aft? Not every boat is the same or balanced the same.

So even if the WEIGHT is only 60% aft once you extend the lenght forward from the CG you will move the fulcrum point forward also, therefore also moving the CG.

 

[superbenk]

Re: damage from keel roller brackets

I agree with ALL that on I/O's, though not every boat is an I/O. Will also agree that on every boat the CG is aft of midship but the question still remains how far aft? 50% aft, 75% aft? 90% aft? Not every boat is the same or balanced the same.

So even if the WEIGHT is only 60% aft once you extend the lenght forward from the CG you will move the fulcrum point forward also, therefore also moving the CG.

Fair enough, but I'm not really sure what the point is.

The OP definitely has too much boat sitting on the keel rollers and too little bunk. The original suggestion to re-distribute the weight still stands and will help loading significantly IMO.

 

[a70eliminator]

Re: damage from keel roller brackets

I don't know what your trailer looks like but if it's anything like mine (flat not V)
It's not a drive on easy load trailer, if someone tries to load it like one they will miss the mark about 90% of the time and the rollers brackets will gouge the keel every time, it happens sometimes even when guiding it on by hand, usually when someone tries to help me.
The keel rollers do support most of the weight on this trailer design, well these have been for 40 plus years.

 

[bonz_d]

Re: damage from keel roller brackets

The original post was for damage to the hull from the roller mounts, not the rollers, as I understood it. Which in my opinion would be caused by improper loading of the boat and not a fault of the trailer. Meaning somehow the keel got off of the rollers while loading.

It then was suggested that the trailer is set up wrong and there is too much weight on the rollers. But to me, sense the trailer was designed with SHORT bunks it was meant to be used as a Keel roller trailer were the magority of the weight is supposed to be supported by the rollers and not the bunks.

Look at it this way. Were there are short bunks (meaning up to or just past the CG) and the bunks are firmly fixed to the trailer fore and aft the forward edge of the bunk becomes a fulcrum. The further the CG is moved forward the more the weight come to rest on that forward edge of the bunk and less weight on the aft end.

If the bunks are mounted on a center piviot that point becomes the load point were the whole weight will be evenly distributed over the bunk and then placed on the piviot point. Just like the axle of the trailer is a fulcrum or piviot point. Some times the axle needs to be moved to get the proper weight distribution.

 

[jkust]

Re: damage from keel roller brackets

I can tell you damage caused on a roller trailer from those roller brackets is from having one wheel higher than the other and trying to load anyway. Usually from a bad back up job or uneven ramp service. The winch will yank the boat on but damage the bottom. You will hear the scraping sound however to warn you. The roller trailers while offering some superior technology to bunks have one of their downsides as the need to be pretty level to load.

 

[Cannondale]

Re: damage from keel roller brackets

Well, I've read the various posts about the OP's trailer and am astounded that it's being suggested his trailer is set up wrong.

Guess my late 1960's Dilly tilt trailer, which supports a 15' tri hull fish-n-ski boat, is wrong from Dilly, too. It uses a series of 5 keel rollers with a pair of 2 1/2 foot edge mounted bunks at the rear of the trailer. The bunks, which are only 20% of the length of the boat, are used to center the boat on the rollers, not support the entire weight of the boat.

Just like the OP's trailer, there are those older trailers that do use the keel rollers for weight support and very short bunks at the rear soley to keep the hull upright on the rollers. But these type trailers are very much an older style and, granted, are not really seen much these days or used any longer.

But to just dismiss the OP's setup as being wrong and such is just to demonstrate the lack of knowledge the poster of such drivel is displaying.

Sorry about that, but it is fact. Keel rollers being used for supporting the entire weight of the boat isn't strange, odd, or weird or wrong. It was just a way it was done waaaay back in the day.

 

[superbenk]

Re: damage from keel roller brackets

I didn't mean to say the trailer was set up wrong necessarily, but adding longer bunks can help with loading a boat and supporting it. Bunks have much larger contact area than any given roller, so I don't see how that could be disputed. Maybe that's how it was done way back in the day, but it's also possible that it's not done as much now for very good reasons.

Also, the OP was looking for suggestions to help keep that kind of damage from happening in the future and make loading a bit easier. Extending the bunks & adding wider rollers as I said could absolutely help that whether the original trailer technically needs it or not.

 

[bonz_d]

Re: damage from keel roller brackets

The OP definitely has too much boat sitting on the keel rollers and too little bunk. The original suggestion to re-distribute the weight still stands and will help loading significantly IMO.

By this statement you agreeing that the trailer is set up improperly and that it needs more weight on the bunks.

Please explain how longer bunks will help loading or are you converting a Keel roller trailer to a bunk trailer? Such as in my trailer there is no way to make the bunks any longer forward than they already are w/o a very large expenditure. In which case it would be cheaper to replace the trailer.

Yes I agree bunks have a larger contact area as long as the contact is uniform along the whole length as I tried to explain previously. I will stick with my thinking that with short bunks the bunks are not designed to support the majority of the weight but are meant to provide lateral support.

I have described my trailer and how it is set up too many times here already and believe it to be correct. This is a Keel Roller and loads and unloads effortlessly!

 

[Fed]

Re: damage from keel roller brackets

The trailer has 4 keel rollers that support the boat with short bunks on sides to stabilize it.

I guess that says it all.

Depends on how your going to load the boat on.
Winching all the way, no problem so long as the rear roller is at water level the winch will pull the boat straight as it goes over the back roller. Your trailer was made to do it this way.

Driving on or floating on could easily see you on the outside of the rollers.

 

[jeeperman]

Re: damage from keel roller brackets

Just got this boat cheap, 16' Ebbtide v-hull runabout. The trailer has 4 keel rollers that support the boat with short bunks on sides to stabilize it. The previous owner kept the boat in the water most of the time, but there is damage that looks like the keel roller brackets digging into the gelcoat when it was loaded. The rear roller is 12", the rest are 4". I'm afraid to repair the damage without adressing the problem first since I will be loading/unloading with every use. What is the best way to prevent that type of damage? I was looking at upgrading some or all of the rollers to 12" and maybe adding roller guides, or both. Any advise is welcome.

I am going to agree with Cannondale. Note the statement in the OP.
"Short bunks to stabilize", which could be merely be carpeted "bunk" style guide-ons.
Not short bunks under any part of the hull.

Maybe you (tcurtsinger) might look at larger diameter, wider and self-centering keel rollers.
Then look at making the brackets more fiberglass friendly via altering them to be smaller, smoother and maybe edge protected with some poly edging, etc. Maybe need some poly crossmember covering either side of the roller too.

But just being sure the boat is centered before it hits any roller should also eliminate damage. As posted, the trailer not being level from side to side is not going to help matters.

 

[tcurtsinger]

Re: damage from keel roller brackets

As I stated in the original post, the bunks are very short and no way they could support all the weight of the boat, but I'm sure they do support a little. The keel rollers are adjusted where all are contacting the boat while loaded. I understand a lot of people do not like these types of trailers but this is what I'm working with. It appears the boat is was coming off the second or third roller while loading causing hull damage. My question was for anyone with similar trailers and would larger rollers towards the front would help keep it on the rollers. Could have been backed in too far but no way for me to know. I am going to fix the damage this fall but I want to make sure I dont damage it again in spring. I would take it and practice loading but the motor is also a fall project. I think i will replace the back three rollers with good 12" poy rollers and then see how it goes from there, maybe guide posts later.

 

[bonz_d]

Re: damage from keel roller brackets

There are a number of reasons that could cause this. From loading with the trailer too deep to loading in a stiff current or crosswind to just plain poor practice or lack of concern.

Guides would help keep it in position though as stated loading the boat with the transom roller just under the water and wenching up will definately prevent it. Remember this is not a drive on trailer and if that is what you are intending to do then I suggest getting a different trailer.