Lost A Bunk

[cozilla]

Decided to try out Mountain Island Lake yesterday for the first time. When I launched the boat I saw a bunk floating in the water and didn't think anything of it. Then once we got the boat back on the trailer after a few hours of fun in the sun we trailered it back to the storage place about 15 miles away and I just happen to look under the boat and bam the starboard side outside bunk was missing. So now my question is what should I do to replace this lost bunk? Does anyone have the measurements for that outside bunk of a MFI trailer for a 2007 SX230?

 

[scokill]

How did you get it on the trailer without a bunk??/ What is the boat sitting on? The bunk will be the same measurement as the other side.

 

[1rjclark]

Decided to try out Mountain Island Lake yesterday for the first time. When I launched the boat I saw a bunk floating in the water and didn't think anything of it. Then once we got the boat back on the trailer after a few hours of fun in the sun we trailered it back to the storage place about 15 miles away and I just happen to look under the boat and bam the starboard side outside bunk was missing. So now my question is what should I do to replace this lost bunk? Does anyone have the measurements for that outside bunk of a MFI trailer for a 2007 SX230?

Measure the other side. It worked out great for me. I used pressure treated wood. My original bunk was pretty bad and I knew it wouldn't last another dunk. When I went to unscrew it it just lifted off. The carpet was holding on. It's not hard. Measure twice cut once. Good luck, I'm sure you got it

 

[Scottintexas]

my aft starboard outside bunk is 61 inches

 

[cozilla]

Measure the other side. It worked out great for me. I used pressure treated wood. My original bunk was pretty bad and I knew it wouldn't last another dunk. When I went to unscrew it it just lifted off. The carpet was holding on. It's not hard. Measure twice cut once. Good luck, I'm sure you got it

Thanks. Problem is I don't have the boat at my house. I can make a special trip down there which is probably what I will need to do anyways.

How did you get it on the trailer without a bunk??/ What is the boat sitting on? The bunk will be the same measurement as the other side.

Its sitting on the inner bunks and the port outside bunk.

 

[cozilla]

my aft starboard outside bunk is 61 inches

Are they just 2 x 6 inch boards?

 

[1rjclark]

Are they just 2 x 6 inch boards?

Yep

 

[cozilla]

Thanks @1rjclark

 

[Bruce]

I replaced the bunks on my trailer last week.

I would replace them all while you are at it.

Here is my writeup including dimensions and materials Replaced bunks on MFI trailer

 

[cozilla]

I replaced the bunks on my trailer last week.

I would replace them all while you are at it.

Here is my writeup including dimensions and materials Replaced bunks on MFI trailer

@Bruce this is perfect! Thanks!

 

[Glassman]

When you replace the bunk boards it's best to use through bolts (countersunk) instead of the lag bolts M.F.I. uses. You can build the boards in advance and then just pop them on the next time you launch.

To the OP: Be very careful when you launch - you'll have to rig up something to protect your hull from scraping on the steel posts that supported that missing board. If you can slide a temporary board between the post and hull that's even better.

 

[Ronnie]

When you replace the bunk boards it's best to use through bolts (countersunk) instead of the lag bolts M.F.I. uses. You can build the boards in advance and then just pop them on the next time you launch.

To the OP: Be very careful when you launch - you'll have to rig up something to protect your hull from scraping on the steel posts that supported that missing board. If you can slide a temporary board between the post and hull that's even better.

x 2 and maybe duct tape it in place to hull and / or post for now.

 

[maboat]

Are they just 2 x 6 inch boards?

2 x 6 yes, but be sure to use pressure treated lumber, not just standard 2x6's

 

[Bruce]

@Bruce this is perfect! Thanks! Where did you get the bunk carpet?

A local sporting goods store had it on a roller already cut to width.

Others have bought from this seller on Ebay http://www.ebay.com/itm/BLACK-12-x-..._Accessories_Gear&vxp=mtr&hash=item2ec8f60381 .

@Glassman, I considered countersunk through bolts. But decided it was not worth the extra preparation. I would prefer to replace the bunks frequently enough to avoid the issue of the lag bolts coming through the bunks. Knowing that I can change the bunks in a couple of hours for around $70 I will change them as often as they start to look bad.

 

[Bruce]

2 x 6 yes, but be sure to use pressure treated lumber, not just standard 2x6's

When I was looking for materials to replace my bunks I searched for information on bunk board materials. The chemicals currently used in treated lumber can cause corrosion in metals and might otherwise cause staining. The factory bunks were not treated. I decided to use untreated spruce and change them more frequently if needed.

 

[cozilla]

Thanks everyone for the info!

 

[Glassman]

A local sporting goods store had it on a roller already cut to width.

Others have bought from this seller on Ebay http://www.ebay.com/itm/BLACK-12-x-..._Accessories_Gear&vxp=mtr&hash=item2ec8f60381 .

@Glassman, I considered countersunk through bolts. But decided it was not worth the extra preparation. I would prefer to replace the bunks frequently enough to avoid the issue of the lag bolts coming through the bunks. Knowing that I can change the bunks in a couple of hours for around $70 I will change them as often as they start to look bad.

I understand your point, however, if you have to drill one hole for a lag bolt you can just as easily drill that hole all the way through and then just change bits and enlarge the top side so that the head of the through bolt drops below the surface of the wood. Then just a dab of 5200 or whatever sealant you have handy on the bolt head as a precaution and then wrap and staple your carpet (SS staples if you can find 'em) and you are done.

If my OEM boards had been through bolted they would have stayed put - instead the damn little lag bolts just dropped out of the wood. Fortunately one lag bolt hung in there long enough so that I could see the board bobbing around as I pulled off the trailer. What I find amazing is that one board out of four was shot. All the others just fine and the lag bolts were tight. The carpet was actually ok....worn in just a few spots from not putting the trailer in deep enough first to wet the bunks.

 

[jetboater4life]

Some info on pressure treated lumber and the hardware used with it.
http://woodworking.about.com/od/safetyfirst/p/SafeACQLumber.htm
http://www.postcaps.com/literature/acqfastener-216.pdf
http://www.popularmechanics.com/hom...working-with-pressure-treated-lumber-15655848

 

[Bruce]

Changing bunks is a very debatable task with lots of opinions, most of which are correct in their own way. I do not claim that the method and materials that I chose are the best way to do it. It was quick, easy, cheap and I would not mind repeating it in five years.

@Glassman, my carpet gave out first. The lag bolts were rusty but holding fine. So my assumption was that I would be making the next change based on carpet wearing out again. My plan to use through bolts had been to measure accurately then drill the holes on a drill press, then install the carpet. I worried about what would happen if the bolt head spun or if my measurements were a little off.

@cozilla, I wonder if you may have had treated bunk boards from a previous change and if the treatment might have eaten the lag bolts.

 

[maboat]

The factory bunks were not treated. I decided to use untreated spruce and change them more frequently if needed.

I forgot to mention that galvanized (or stainless) bolts should be used too.

The factory boards rot and the factory bolts rust. When it came time to replace I chose to replace with something intended on getting wet