Bowed trailer bunks

[Frank O]

I have a mid-1990s two-axle Loadmaster trailer that came with my 1995 Boston Whaler 21' Outrage when I bought it three years ago. The year after I bought it I had new bunk carpets, LED lights and new brakes installed. I believe some or all of the bunk timber may have been replaced at the same time.

The boat is in a slip year-round, so for most of the year the trailer sits outdoors in a storage yard here in Southern California. It's only used once a year to pull the boat out of the water for annual maintenance.

Today when I went to check the condition of the trailer, I noticed that its bunks are bowed:

http://www.inkbox.net/whaler/trailer/bowed-trailer-bunks.jpg

As you can see at this link, the left center bunk is bowed the most, but all are to some degree. The carpet appears to be in good shape, though, and I don't see any evidence of rot in the wooden bunks.

What do you think? Will the bunks tend to straighten out when the boat is placed on them? Or should I really replace them before using the trailer this year?

 

[freddyray21]

Re: Bowed trailer bunks

the bunks will most likey conform to the boat, but where are your center rollers? Looks to be an odd set up if the keel is just resting on the cushioned pieces.

 

[Frank O]

Re: Bowed trailer bunks

Here's a view of the entire trailer:

http://www.inkbox.net/whaler/trailer/loadmaster.jpg

Just forward of the bunks is a V formed by a pair of PVC pipes on a metal fitting, but I don't think the boat rests on this -- I believe it's intended to help guide the boat up onto the trailer.

In my case, the bunks work fine with no rollers, as the boat is always placed on and taken off the trailer via a hoist. But the trailer is configured the same way it was when I bought it, and the previous owner used it this way launching from a ramp a couple of times a month for 10 years.

Is it normal to have rollers in addition to bunks? The only thing I remember on the topic was reading advice somewhere not to go with rollers alone, as supporting the boat only on them would cause the hull to delaminate.

 

[roscoe]

Re: Bowed trailer bunks

The pvc V at the front, is designed to keep the bow from scraping the trailer frame during launch and load only. If you would launch at a ramp, as you backed into the water, the stern would float, forcing the bow downward against the trailer and SCRAPE !!

Using the trailer as is, for your maintenance, would probably be ok.

If you were to use it to launch from a ramp, it would be difficult to load and center properly.

Doubt it would do any damage.

 

[Barnacle_Bill]

Re: Bowed trailer bunks

Not all trailers have both. The last 2 I had had bunks only.

 

[Al Kungel]

Re: Bowed trailer bunks

X 2. My shorelandr trailer only has the bunks, not both.

 

[Home Cookin']

Re: Bowed trailer bunks

whalers are designed to sit on rollers under the keel--at least the old ones are. but for temp use, and hoisting, don't worry about it.

 

[Texasmark]

Re: Bowed trailer bunks

Frank,

The white PVC appears to be a guide to help align the bow to the chock on the front of the trailer. Would appear to be a drive/winch on aid.

Appears the center bunks can pivot. No biggie, just a question/observation.

The starboard is obviously bowed, but hard to tell about the port one from the picture. If both are bowed the same it would lead me to believe that this conforms to the hull and would be ok.

Otherwise I'd say that over time, the weather has done a number on you. With the top of the bunk in the sun, any moisture collecting on the bunk would gravitate to the under side and the natural process of evaporation would favor expansion on the bottom due to the wet wood and shrinking on the top from drying out more easily which is what you have.

Rollers are only necessary for normal drive/winch-on operations with the trailer submerged in the water. Hoisting doesn't need them. They can cause hooks in the hull if not properly adjusted to the hull and the hull is of the type that is sensitive to spot pressure.

I didn't notice that you mentioned how far you travel when you remove your boat from the water. If you only pull it a short distance, it may not matter that the inner bunks are not correctly in contact with the hull.

Otherwise, I'd replace them, which probably is the best thing to do anyway as treated pine isn't that expensive and the procedure is straight forward. On the carpet, I never replace it when I change bunk material.....no carpet means the bunks dry quicker and have less chance to do what yours have done.

Good luck,

Mark

 

[eli_lilly]

Re: Bowed trailer bunks

The trailer is a standard float-on configuration and it's the most common trailer style here in South Florida. The two outer bunks support the majority of the weight. The inner bunks would support no weight.

During rigging, the front v-block is loosened and the boat is set on the outer bunks with the hoist still very slightly supporting everything. The vblock is then pushed up against the hull and tightened.

The two bunks in the middle are guides for the back, to keep the side of the boat from sliding off the main bunks while loading. They should be lightly against the hull and should not be supporting any weight.

The middle bunks are warped. If the warping conforms to the hull shape, it's fine, since these bunks should only touch the hull.

I can't tell if the main (outer) bunks are warped vertically or if its camera lens distortion. Vertical warping can be intentionally done during rigging to allow the bunks to conform to the hull's curve, you will know this is the case if the brackets in the front are further in than the brackets in the back. If the main bunks are warped horizontally, which I can't tell either, the bunks would need to be replaced.

-E