Boat Lifts with Stepped Hulls
 

Maybe there is a thread out here on this topic, but I did not find it. I have a Donzi 27ZR with stepped hull (2 steps). I am thinking about purchasing a boat lift. Probably a Shorestation. My question relates to the bunks on the lift. On my boat trailer, the bunks are stepped to match the hull. This way no weight is being put at the point of the steps. I would assume that I would have to have a similar setup on my lift.

I called my Shorestation dealer here, and he had asked Shorestation corporate about this issue before, and they didn't really match the bunks with the hull steps. They simply set up the bunks on the lift so that they angle up towards the back of the boat, so the boat sits level once hoisted (in other words, the bunks on the lift are straight, and not stepped to match the hull). This would seem to me to not be the ideal set up. Seems to me that there might be too much weight on the point of the steps, which I wouldn't think is good for the hull.

Any thoughts on this?

Rick

I was worried about that too. So, I took all the measurements and put the steps in my bunks on my lift. Just to ease my mind. Not sure if it effects the hull but i would think it does if its out there all season or longer.

My .02c

From a pure engineering standpoint, matching the bunks on the lift to the hull is very desireable so as to evenly distribute the force / weight. This is important not only for the hull, but the bunks as well.

Just remember that you will have more of a "one way ratchet" effect on the lift where the boat will not want to back out - because of the steps - until the bunks are fully clear. You occasionlly see this on trailers in a shallow launch, but the trailer is angled. Your lift bunks will be horizontal.

I assume for a 27' Donzi or any other smaller lift, like ours. You will have (2) mainframe members that your bunks bolt to. If the shorestation lift bunks is built anything like the hydrohoist or boatfloaters - they just flex and bend with the boats bottom (not step) contour. Most of the boats weight is carried right at the bunk mount to the mainframe area.

Unless you have a step within a foot..., foot and a half, from the bunk mounting point - i wouldn't sweat it.

Absolutey cut or add to your bunks to make it match your step bottom. If your lift manufacturer won't do it, they are lazy.

You run the risk of chipping the edge of your steps due to the weight stress, or worse, deforming the hull over time.

The bunks on your lift should be narrow enough not to hit your steps. My sunstream lift bunks are only 30" apart.

I have a 35ZR on a ploy lift ay LOTO
I called the factory, got a drawing from them used to set up trailers.
The drawing gave exact mesurments for the size of the steps.
Got some pressure treated lumber.
Had a buddy with a plainer cut them down to the proper thickness.
Mount to rails, new carpet on bunks.
Problem solved, perfect fit.

Sorry, but this is common sense, and shorestation has none apperantly. Your boat doesn't know if it's sitting on a trailer or lift. It does know if it's sitting on an edge. Match the bunks to your boat, as your trailer is.

Mine just took an extra 2x4 on top of the lift bunks to match the step height. They do not have to be the full length of the steps. Keeo them a little short towards front so the boat has a little room to move w/o catching the edge of your step as it raises or lowers. Mine start a approx 12" back from step.

Um, my boat lift is not pulled behind my truck at 60 mph around corners and over bumps. A lot of us have our boats on lifts without custom bunks. Just enjoy. Common sense??

Do you like the bottom of your boat the way it is??? Proper support is critical.. your money..