boat lift for 2018 R27

[Matty]

Does the listed weight of the 2018 R27 per the site include the outboard motor weight? Site indicates a weight of 7,000. Adding fuel, water, personal effects I come to about 9,100 Ibs. This is with maximum fuel and water which I would not normally have but you never know. Would a 10,000 ib weight be cutting it to close? If so I imagine 12,000 should do it.

 

[mjq1987]

Matty,

I can't answer the specific R27 weight questions, but, in my opinion, 10% margin (in addition to whatever design factor is already incorporated into the lift design/construction) is not enough. As you get close to the lift capacity limit, the margin for error for having the boat's actual center of mass (CM) not in the exact center of the lifting points goes way down. The CMs shown for the hulls in the factory-provided diagrams are likely for dry weights. In our case, the boat's actual CM with full tanks and normal gear was 18" aft of the CM identified in the lift diagram. This makes a big difference in lift beam and cable loading (I won't bore you with the details, but I used a cable tension gauge and measured cable loads in various boat positions to take port/stbd and forward/aft weight measurements). Based on all of this, we went with a 20K lb lift for a 13K lb loaded boat...probably more margin than necessary, but I thought the price differentials for larger lifts are relatively small for the peace of mind.

If you went with a 10K lb lift with a 9.1K lb boat, a 1-ft misalignment of the actual CM from the center of the lifting points forward or aft would overload the pair of cables closest to the CM (over 2500 lbs each). This assumes you have a four post lift or similar configuration. Here's a good estimating tool if you don't want to manually calculate/measure everything: https://stokesmarine.com/load-lift-calculator

Mike

 

[Matty]

Thanks for the reply and link. Makes a lot of sense. I played with the calculator you sent and I can see how close I would be to be out of spec with a 10K. You plug 13K (next size up for the brand I am purchasing) and I can see the much greater margin of error. I think the difference in price is only $1,200 so I will go with it for the piece of mind as you say.