Which boat house bunk system/setup for tri-toon with ESP package?

Economy Mike

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Who knew? Anyone wishing to purchase or care for a Bennington or any pontoon boat should follow these forums daily. That alone would save a ton of money and heartache. And thank you Jeff for your prompt response to my question about lifts. My lake is part of the TVA system of impoundments along the Tennessee River and the water level fluctuates a lot: 5-6 ft drop in winter months and often a 9-10 ft spike in early spring. Depth at my new dock averages 12-15 ft. I have not seen any sea legs down here. For now, I am going to stick with the lift and look into some plastic bunks.
 

Vikingstaff

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Your welcome Mike. Yeah, just based on your water conditions, Sea Legs would not be a good fit. Either a bunk or platform lift will get the job done for you really well. I am partial to the V-bunks myself as they cradle the pontoons so well. However, it’s not necessary.
 

Economy Mike

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We got to move into the new (to us) lake house a few weeks ago...FINALLY! A big storm came through before we took possession and sent the top of a tree down through the roof. After 3 months, the seller's contractor still couldn't not finish the repairs so we withheld some funds at closing to get it done ourselves just so we could take possession. We had the chance to walk away from it, but I thought it was still a good deal (pre-foreclosure plus he left everything behind: furnishings, linens, skis, air compressor, tools, towables, etc. etc. - house and garage full) and it is located right where we want to be. Beautiful sunrises. Shade in the afternoon. Screen porch and sundecks. Covered dock. It was a long, stressful process, but at least not the 6 months Viking had to endure to get his house restored. I feel your pain, Jeff.
Anyway, once we closed on it, I began contacting local dock builders just to convert the lift from accommodating a Malibu ski boat over to our Benny. And of course they are all booked up well into the fall on other jobs. So I think I am going to tackle this one myself. Soon, the local labor force goes on what they call here "Pickwick Time," which is to say you won't be able to find anyone willing to do anything until they are good and ready. And you shouldn't even bother calling anyone if deer season is open. :)
But this can't be that hard to do. I have replaced trailer bunks a couple of times for a previous boat, so I get the concept. And I've seen other posts indicating that you need to fully support the rear end of the toons and that it's 77 inches between the centers of the outside logs. Plus, the seller left some extra bunk brackets in the garage. Am I missing something? Any reason I shouldn't take a swing at this? I am so ready to pull my boat out of the marina and have it right there at the house. Any suggestions? Thanks.
 

russerath

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Economy Mike,
Just bought a house on Lake Hartwell and "Pickwick Time" is well established here.
22 ft Benny tritoon with 150 hp and have to convert lift as you did. Can you share how you implemented the conversion?
Are 3 2"x8"s running the length of the tubes adequate or do I need to make V cradles for each tube?
Should I cover the wood with outdoor carpeting?
Should another material be used vs wood?
Can't seem to find and details from Bennington on supporting requirements.
Any info will help
Thanks
Russ
 

BaysideFMB

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We have three flat aluminum bunks with a rubber/vinyl covering on the top of them.
 

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Economy Mike

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Hi Russerath. When I posted my questions about this project, I got crickets. Then I understood why. Turns out my project was more involved than I was prepared for at the time but, fortunately, I was able to find a marine construction company that had just finished a big project and was able to fit me in. Back then, I did not understand the different bunk supports, as I have a bladder style lift and wanted a v-bunk setup to sit on top of it. In the back of the garage at the house we purchased, I found these brackets, which were just what was needed to convert the lift from supporting a ski boat to one that accommodated a pontoon. Pontoon bunk supports have very little rise. I recommend covering the bunks with marine grade carpet, but I am not a fan of wood products around water. Also, I have read on this forum that pressure treated lumber can cause pitting of the hulls. A construction grade alternative, such as Weardeck, which does not have a sawdust core like some of the others, would be my choice. Bunking the entire length of all 3 toons is preferred, although adequately supporting the rear of the center log is critical. Dimensionally, I think 2 X 8's are strong enough as long as you don't try to span too far without support. My v-bunks are twin 2 X 6's with supports at about 3-foot intervals. I later added three pairs of C.E. Smith guide-on posts to help me center the boat on the bunks. Good luck with your project.
 

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monica & mike

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help! new to boating, and bennington! just bought ourselves a 2017 SFX20 tri-toon for xmas and need to have our lift modified to accommodate it. the guy who put this lift in had some kind of massive v-hull boat, so the lift is rated for 13k lbs and has a hoist on each side. but the bigger problem is that most lift repair folks I speak to don't seem to know what to do to modify the v-hull cradle to hold the pontoon. i have a guy telling me it's ok to put 2 x 8 bunks in way to the left side and that the boat doesn't have to be balanced in terms of load on the motors. that doesn't make sense to me, but an engineer friend confirms that so long as the boat weighs less than what the left-hand side motor is rated for, we should be ok. also, some folks are saying we don't need to support the center toon individually... but i see lots of comments in this forum indicating most of the weight is at the back of the boat and that would seem to suggest that we for sure DO need to support the center toon. any recommendations?
 

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Yianni

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We were in the same situation when we bought our house. The previous owner had a 34' offshore boat on the lift.
I had every boat lift outfit in the area take a look to retrofit it to our tritoon. They all said it just wouldn't work for a conversion.
I had to bite the bullet and just buy a new lift designed for the pontoons. I sold the old lift on Craigslist.

Welcome and hope you have better luck than I did.
 

monica & mike

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difficult to remove/sell the lift because it's integrated into the frame of the boathouse. but i found a good guy who seems to know what to do. fingers crossed! will post photos when done.
 

russerath

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Thanks all for your responses.
Economy Mike: the weardeck composite sounds like a good solution. My problem is i have a 10 ft span between supports. Another contradiction is the Bennington Dealer says there is no need to support the center tube! They only support the two outside tubes.

Bayside FMB: It looks like you have a long span with the flat aluminum bunks. Is there a name brand of these bunks?
 

Economy Mike

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Everybody has an opinion, but the weight of your outboard plus the center log on an ESP has to be substantial. I absolutely would support the center log, especially at the rear. And a 10' span is way too long, IMO, to use wood or anything else that would sag over that distance. If you can't get some support intervals, you should probably use metal beams like BaysideFMB apparently did above. Good luck and safe boating!
 

monica & mike

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difficult to remove/sell the lift because it's integrated into the frame of the boathouse. but i found a good guy who seems to know what to do. fingers crossed! will post photos when done.
so... he placed two uprights (the right hand one slightly longer than the left hand one due to the angle of the cradle) and laid aluminum bunks on top. the bunks are between the toons, which both the lift guy and the dealer said would be okay (vs supporting the boat via the toons themselves). this also has the advantage of making it easier to hose off the toons. hope this helps someone! if you're in the st. pete/tampa area, happy to provide you with contact info for the lift guy. boat appears to be tilting right but i think that's some kind of optical illusion since it's actually level. ;)
 

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Bill N

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so... he placed two uprights (the right hand one slightly longer than the left hand one due to the angle of the cradle) and laid aluminum bunks on top. the bunks are between the toons, which both the lift guy and the dealer said would be okay (vs supporting the boat via the toons themselves). this also has the advantage of making it easier to hose off the toons. hope this helps someone! if you're in the st. pete/tampa area, happy to provide you with contact info for the lift guy. boat appears to be tilting right but i think that's some kind of optical illusion since it's actually level. ;)
That looks good and will most certainly be fine.
Addressing the misconception that the pontoons need to be supported.....
What about hydraulic legs which distributes the load over a few crossmembers, where a rack like above distributes the load over the majority of the crossmembers.
Clearly, the rack system is an acceptable option and it does not harm the vessel.
 

monica & mike

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That looks good and will most certainly be fine.
Addressing the misconception that the pontoons need to be supported.....
What about hydraulic legs which distributes the load over a few crossmembers, where a rack like above distributes the load over the majority of the crossmembers.
Clearly, the rack system is an acceptable option and it does not harm the vessel.
bucky/bill! we also hail from wisconsin and are long-time badger fans. are you still living there?
 
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