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I dont think I buy the roller dimpling thing?
|Author||Topic: I dont think I buy the roller dimpling thing?|
posted 07-03-2002 01:07 PM ET (US)
SOME recent activity on bunk vs roller trailers. Many other post I read have me scrambling to West Marine to fix something I didnt know was broken.
My classic 16 is trailered about 5 months each year on ezload roller trailer (oversized for 2500 lbs). It has 16 rollers each about 8 inches wide, 3ft apart(front to back)2 ft apart(side to side)with only about 4 inches from keel and toed right under the transom. I figure my load is about 1600 lbs at worst.
Mathmatically, that places about 100lbs on each roller (or maybe 200 under the motor) and Im just not sure I can buy into the fact that this is causing hull dimpling and delamintation.
She is 39 years old, and been with this trailer about 10 years and appears as smooth as the day they made her.
Not trying to be argumentative, but common sense tells me atleast in my case that the unsinkable legend can handle 100+ lbs pressure without falling apart.
posted 07-03-2002 01:17 PM ET (US)
All I know is that on the 25-year-old 15' that I just bought, the hull goes in about an inch where it meets the aft-most roller. As soon as I bought the boat, I raised the bunks to take some pressure off of this spot.
posted 07-03-2002 02:35 PM ET (US)
I could be wrong, but I think you might not completely understand what the conditions are that caused BW enough concern to mention a warning about roller style trailers in their Owners Manuals.
You have to keep in mind how a Whaler is built and how it gains structural integrity, as opposed to the same factors in other boats. The Whaler basically has an inside skin and an outside skin with a layer of expanded foam between the two layers that is chemically bonded to both inside and outside layers at its birth. Of course the expanded foam is much less strong than either if the skins. Nonetheless, as long as all three components remain bonded together, and the foam itself remains intact, a structural unit is developed that is stronger than any of the three components by themselves.
The concern regarding rollers is that, (particularly when the trailer does not have keel support of some sort to take up the majority of the weight of the boat, as per BW recommendations), as the weight imposed on each of the rollers is shifted by the boat either being loaded or unloaded, the outside skin will flex and that flex will move along the hull, following the roller as the boat moves. The degree and amount of flex certainly is dependent upon a number of factors, (keel support, number of rollers, size of rollers, weight imposed, etc.) but in the worst case scenario, *and it does happen*, either the bond is broken between the outside skin and the foam, the foam itself fails internally (with similar symptoms to de-lamination), the foam compresses at the rollers, or some combination of the three.
The hulls of fiberglass boats that are not structurally similar to BW, that is that do not have an internal, bonded layer of foam upon which they rely for structural integrity, can roll and flex to their hearts content at the rollers, as long as the fiberglass holds up, *because there isn't anthing bonded to the skin that the flexing will detrimentally affect*.
The most conservative approach, and it is not for everyone, is to do exactly what BW recommended; support the weight on the keel (which is most easily done with rollers) and use bunks to keep the weight of the boat concentrated on the keel support. There are other less conservative approaches, and some of them will work fine over the life of the boat given certain assumptions and conditions, and some of them won't.
I don't know what kind of trailer your boat rested on for the first 29 years of her life, but I'd say so far you have beaten the odds as BW saw them.
posted 07-03-2002 03:04 PM ET (US)
Kingfish, you are stating that the roll effect (like a rolling pin)at launch and load is where alot of this damage occurs;a point that makes since.
I normally dunk the trailer and allow the vessell to float over most of the rollers. I never really "crank from dry" because I never wanted that much pressure on the front eye latch (had to replace it once)
My concern was that the weight once trailered would push the dimples in.
I will probably keep the trailer for now, add some keel rollers for better weight distribution, and keep my non stress launch and load procedures in tact.
posted 07-03-2002 03:12 PM ET (US)
Kingfish, Should I forget about my dimple or try to repair it somehow? The 15' does not have a keel at the stern so the roller there has caused an indentation that is about a foot in diameter and goes up maybe an inch in the center.
posted 07-03-2002 08:20 PM ET (US)
I am not looking to debate this but to share with you my personal experience. All roller trailers
that are worth their slat can have the rollers adjusted so that they are almost touching at the keel.
In my case I have a 78 Newport 17' on and EZ Loader all roller trailer. With the rollers adjusted
close together it resembles a keel roller at the keel, with the upper rollers acting as supports. I
have used this setup for several years and no dimpling at all. It loads very easy and unloads for a
joke.... Having said that I have worked for a local whaler dealer for years and we sold roller
trailers with most of them... and have not had any problems.... The biggest problems would arise from someone adjusting the rollers so it would dig into the chines on the 17 foot models... But if someone takes the time and sets it up properly a roller trailer can be very effective. I have to add that BW does recommend bunk trailers to clear the air.... just my 2 cents worth.
posted 07-05-2002 10:01 AM ET (US)
Thats true on the adjustment although I have never thought/done that. I could actually get the rollers to touch at the keel; Im not certain I would go that close but i will probably make some changes to give keel support
posted 07-05-2002 11:21 AM ET (US)
I've got a '74 Montauk on a '77 EZ Loader Roller trailer. My trailer is setup as newportguy describes with the inner rollers positioned very close to the keel. So far I haven't noticed any problems (of course now that I've written this...). However, after reading kingfish's post I'll probably be backing the trailer further in than before.
|The Chesapeake Explorer||
posted 07-07-2002 08:47 PM ET (US)
I just posted on the repairs page about my 87 17ft Montauk. It has been trailered at least 50 thousand miles. It has a bump in the hull from the center roller on a bunk trailer. Its about 1/8 at the most and the spot is about 2X6 in a oval The gel coat has come off in a spot about the size of a half dollar and there is a fine crack into the green glass which weeps a bit of water, though I do not think the hull has much water in it. I detailed what I think I will do for a repair on the repair page. The bottom line is that my bunks had gotten loose with rotted fasteners and I did not keep on top of it, so too much pressure was on the center roller. I will add another member to the trailer to give another roller support. Although I have caught this problem in a early state, If I had known this would happen I would have gotton extra rollers on the bunk trailer when the boat was new. It all boils down to taking care of the trailer.And I can understand the flexing situation of the all roller trailers.
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