Which type lift supports are best - under toons or decking?

[baswinfo]

I am new to this forum and haven't seen related topic.
I just bought a used 2005 24' Crest Savannah tritoon (26" dia toons) with 200 hp Merc EFI (2001). I am about to modify my lift at Smith Mountain Lake in Virginia to handle this beast. Existing lift cradles, motor, pulleys etc are too far into the dock to accommodate this boats center of gravity, so that stuff is being moved and newer 9'6" cradles obtained.

The installer fellow says we should do what the manufacturer recommends in selecting type of supports in the lift. Since I have not been able to get the folks at Crest to call me back with the answer, perhaps someone on this forum can tell me whether I should support the boat using under deck vertical supports with PT 2x10s or a set of three carpet covered Vee supports mounted on the cradles. The boat has aluminum sheet metal covering the underside of the deck.

The installer says the vertical "between the toons" support for the underside of the boat deck can serve as a better guide to berthing the boat. Would seem to make sense, but I am concerned about the flexing of the deck every time we take the boat out of the water and let the toons hang their weight. Would this not eventually loosen the joints between the toons and the decking?

Thanks for responses.

What did you end up doing my Tritoon will be ready tomorrow and I also have underskin panels and lift is configured to lift the deck vs the toons wandering if I should switch????

[Marc K]

baswinfo, that post was over 9 years ago and the original poster never came back.

I would check with the manufacturer of your boat. It occurs to me that pontoon boats are designed to ride with the weight on the tubes, so hanging the tubes unsupported from the deck members just doesn't feel right. That opinion is worth exactly what you paid for it!

Marc

[BobL]

so hanging the tubes unsupported from the deck members just doesn't feel right.

Doesn't feel right to me either. I would only use bunk style (just like a toon trailer).

I have also seen damage to boats that use strap lifts. If you don't have the spreader bar spaced properly, it will stress the tubes.

[steve1313]

99% of the lifts on my lake just have a single 2' x 8" laid flat across the lift crossmembers, positioned under the center of each toon. The only situation where this won't work properly is when the center toon is larger than the two outside toons. In those cases, they typically create the V bunkers under the two outside toons, raised high enough so that the center toon doesn't touch the crossmembers.

[Marc K]

Most lifts for pontoon here are v-bunks like a trailer, but there are several pontoons hanging on slings - including mine.

When I bought the house, the boat was already hanging in the boathouse on the slings and has been for over 13 years now. This is not how I would have done it, but I couldn't see why I should feel compelled to change it after so many years. I replaced the cables and pulleys, but the straps are obviously not very old. FWIW, the cables and slings are only slightly off of vertical, no serious angle at all.

[Puto]

How can I resolve this issue? My toon cradle bunks don't fully connect on the outsides because the lifting strakes are resting on them. For what it's worth, the brackets holding the cradle wood (PT Lumber) are fixed one piece, so there's no adjustment of the angle of the wood.

[steve1313]

Puto - It's tough to get those kind of "cradles" to line up perfectly. I think that's why everyone on my lake just uses the flat piece of 2 x 8s.

[Puto]

Thanks Steve. I just hope I'm not causing any damage to the tubes or strakes by the boat's weight resting there. :crossed fingers: The number of reliable, professional, competent dock and lift guys in this area (with two connecting lakes equalling over 30,000 acres AND a 625 mile river) can be counted on one hand. I asked my contact guy to prep the lift for a tritoon back in March. He showed up July 30 to do the work.

[steve1313]

Here's an example of how my lift is. It's the same basic setup as almost every other toon on our lake.

lift1.jpg (172.27 KiB) Viewed 4220 times

[BobL]

Pluto...not sure if those are 6” or 8” wide but for sake of discussion, I will use 6”. On the inside bunk, you could add a 2x4 the length of the inside bunk but come down 2” from the top so it won’t touch the strakes. On the outside bunk, it looks like the rear 1/3 of your bunks aren’t touching the toon. On that side, I would add another board in the last third section to increase the thickness in the area where the toon is not touching. Make sure to do a deep counter sink on your screws if you do this.

[Puto]

^ Thank you, I really appreciate your input and advice. I think that's a great idea. That should take up that gap and allow them to sit fully on the lumber. No issues with the inside bunks sitting on the weld of the strakes to the tubes?

Great forum filled with great people with great advice

[BobL]

No issues with the inside bunks sitting on the weld of the strakes to the tubes?

I dont think you should have any issues with the welds on the strakes if you set the second board in such a way that it raises the tube high enough in the middle. Hell, those welds will likely hold up fine the way it sits but I am anal (ha ha) so would do some modifications.

What I am suggesting is how to deal with your existing setup. If you think about it, 2 x 4's would accomplish this as they would be a long way from the strakes when the toon sits in them. Most people use 2x6 or 2x8 because they don't have to line up perfectly - lots of forgiveness room. In your case, the 2x6 (or 2x8) width and the angle is interfering with the strakes.

The way I see it, your options are:

If you don't want to replace or rip existing bunk.
1 - add wood to the bunk that is interfering with the strake (as previously suggested)

If you want to replace what you have.
2 - if those are 2x8, replace with 2x6 on the bunk that is interfering with the strakes.
3 - if those are 2x6, replace with 2x4 on the bunk that is interfering with the strakes.
4 - rip the board (make is less wide - cut 2" off) that is interfering with the strake.

DISCLAIMER - I am not an engineer but have spent a lot of time adjusting bunks.