Trailers : "Tilt Bunks" vs "Fixed Bunks" ?

[RebelYell]

..

Howdy everybody.

I am looking to buy a new trailer for my 20' 1990 Osprey and I would like to get some opinions before shelling out $$$...

I am looking at a dual axle galvanized trailer that has tilt bunks......what are the advantages / disadvantages of tilt-type bunks vs fixed bunks ? I would appreciate your valued input !

Thanks -

 :jocolor:

[fitz73222]

Good morning RebelYell,

I like tilt bunks over fixed bunks because rarely have I seen fixed bunks that actually matched the hull angle correctly. The result is a single point of contact due to the disimilar angles and will cause gelcoat abrasion and bunk carpet wear thru very quickly. Plus the hull is not supported across a broad surface as it should be. I just had to repair the gelcoat and replace my bunks and brackets for that reason. The previous owner was not bunk savy and the wear on the hull was through the gelcoat and a 1/16 into the glass for a 4 foot stretch! Not pretty!

Fitz73222

[Circle Hooked]

Tilt bunks allow you to launch or load in less water,that's what there designed for, with fixed you need adequate water to cover the bunks or you'll get wear on the hull like fitz said,you'll get alot more life out of fixed bunks,no moving parts, and as with any bunks if you start seeing ware on the carpet you need to replace the carpet.

fitz please don't take any of that the wrong way.

[GoneFission]

If fixed bunks are properly adjusted, you get solid contact with the hull for a very long length.  Also, I think fixed bunkks can work better in shallow water because you can mount the bunks lower on the trailer - you don't need the height of the pivots under the bunks.  

Regarding hull wear and carpet, go with the Slik-Sticks over the carpet or just replace the carpet with the sticks.  The boat hull slides easily on the sticks - in fact, you've gotta be careful when you are launching to not disconnect the winch before you are ready for the boat to slide off the trailer.  The boat slides so easily that it will slide right off the trailer on the ramp incline.  

Just my $0.02...  See ya on the water!

[gran398]

Good points guys. To me, guess it depends on what the main use is.

If the boat is left on the trailer all/most of the time, then I'm with Fitz; You'll have much better support, in a myriad of strategic places, with the roller bunks. The boat keeps it's shape with no stress.

But if the boat stays in the water a lot, or on a lift or dry-rack, then the trailer becomes more of an ease of use consideration, a "yard trailer", if you will. That's where a float-on shines, piece of cake to load, easy maintenance.  Them I'm with CH.

How's that for Politricks?....

PS

Ditto with John, especially on the "Slik-Sticks".....they make a BIG difference.

[fitz73222]

Hey Guys,
One other thing we need to consider in offering aid to our brother here is what type of trailer should he buy. The only reason I say this is because I have a center roller support trailer on the 22-2 and i realize it is a little outdated and definately higher maintenance but its what came with the boat and is in remarkable shape for a 77` vintage. That said, and beyond the additional maintenance there are distinct advantages to this trailer type over a drive on type. First, they are much more lousy ramp friendly than a drive on and require far less water to load and unload, the issues are powerwinching and more time clogging up the ramp. I have a drive on with fixed bunks for my Baycraft flats boat and I can be in and out of the water in under 5 minutes which is great for everyone. So I wanted to qualify my desire for tilt bunks verses fixed bunks. OK guys, the waters great! Jump in!

Fitz

[gran398]

Fitz, good thinking.

As Fitz and I own twin sisters, it immediately comes to mind that how can these hulls (our two at least)  be so well-preserved/intact, without rebuild, through the last 35 years?

Mine was babied, pampered. On a covered lift, or in a garage.

Fitz has been a 22-2 aficionado since he was 16 years old. He knew the brand way back when, and searched for and bought a cupcake, he owns one of the only surviving  (quality) 22-2's with original twins.  

I've seen pics of his boat, its a specimen, its perfect. And like any other rarity, less is more. I'm all about an open transom, keeping it classic, keeping it true.

May well be that the reason these hulls are still tight is that they were kept on roller trailers, per issue.

As brother Fitz says, "what came with the boat."

good deal.

[GoneFission]

I've had roller trailers and bunk type - I guess I just prefer the bunks.  One problem with roller trailers is the rollers present stress points on the hull.  If you read instructions for setting up a roller trailer carefully, you will see they want the rear roller directly under the transom, not forward of it.  The reason is that a roller in front of the transom can put a "hook" in the rear of the hull - not a good thing.  

OK, so here's the engineer coming out:     Rollers provide about 1 square inch of contact area per roller.  Lets say you've got 32 rollers on your trailer - that's 32 square inches of contact area for the boat.  Take my CCP at 3500 lbs wet, and divide the weight by the contact area, and you've got just over 100 lbs./sq. in. to support the boat on the rollers.  Now consider a bunk trailer with at least 10 feet of contact area on each bunk and even though the bunk is 4" wide, let's say only 1" contacts the boat hull.  That is 120 square inches of contact area per bunk, times 2 bunks, equaling 240 square inches.  Divide 3500 by 240 and you get about 15 lbs./sq. in. - 85% less stess on the hull than rollers!    

Bunks sometimes get a bad rep because owners don't adjust them to fit the boat.  Also, a long bunk should only be supported at two points so it can flex to match the shape of the hull curve.  That gets rid of the "hot points" on the boat hull and provides longer support.     Here's a shot of my CCP on the trailer - note almost full contact for the length of the 12' bunks:


The front bunks are more for centering the boat when powering back on the trailer, and yes the side bunks help too!  The boat really goes straight on the trailer by herself - which makes Cap'n John look good at the ramp...  I need the help, because I only trailer the boat 3-4 times year, so not much practice...  

 

Hope this helps - see ya on the water!

[gran398]

Your points are spot-on, good post.

Following the logic re the transom-hook, guess in that instance more support (short of the stern) becomes less.

And with the majority of the hull weight to the rear, guess forward support isn't the concern it would first appear.

I've always liked a float-on too, and doesn't leave roller-marks.

Thanks for the good analysis.

Guess in the end it comes down to buyer preference.

[John Jones]

I have to go with Capn John.  A properly set up bunk trailer is the way to go.  I don't remember now which one but I was looking around several years ago and one major boat manufacturer would not warranty their hull on a roller trailer due to the possibility of hull deformation.  

You can't believe how good front bunks make you look at the ramp.  
In fact, these short blocks changed loading my CCP from a royal pain in the butt to a one man job.

[Hardwater]

The trailer under my 222 CCP when I bought it was a good example of the need for the rear rollers being directly under the transom - and why rear rollers being too far forward could lead to a problem - over time.



On our previous boat, we replaced a painted steel roller trailer with an aluminum fixed bunk trailer.  In seven years with the bunk trailer (after 4 years with rollers) we never had problems launching at any ramp we could access.  Looked for a bunk trailer for the CCP and found this barely used galvanized Load Rite for under $1500:



After a year + with this one, there may be times the tilt bunks help out some but it would be a matter of degrees.  Haven't run into a situation yet where the tilt made the difference in being able to launch or haul out.  If price, construction quality, etc. is the same - flip a coin.  If it's a big price difference, I wouldn't hesitate going with fixed bunks.

[flkeysaqua]

Price is definitely different between the two there is more moving parts like others have said with tilt trailers thus more to break and no real benefits in my opinion. So why pay more for a trailer that in my opinion does nothing extra. I just bought a brand new fixed bunk trailer from Rocket the dealer set it up for my boat and she slides off like she has butter on the bunks