Malibu MXZ stern position on boat lift

[rjohn]

Any advice on positioning a Malibu MXZ on a boat lift?  I am interested in understanding the stern position on the bunks.  I talked to a Sunstream dealer he said look at your trailer which I get; however, the boat cannot be position with the bunks at the edge of the stern hull.  Is it safe long term for the the stern hull to sit over the bunks by 15 to 24 inches?  Will this cause fatigue of the hull with the weight of the engines etc.

 

thanks

[hethj7]

15-24” you are probably fine.  I am not sure what the max would be.  
 

This was my 25LSV on a newly installled Hydrohoist.  
 

 

[familyfun]

Based on the picture and it being a 25 LSV, I am guessing the lift is an 8800.  The 8800 comes standard with 14' bunks, which based on how far they stick out looks like what is there.  You can get them with 16' bunks which stick out further and have an angled brace.  I have the 8800 with 16' bunks for our 25 LSV and the bunks come within about an inch or two of the transom (the bunks go back almost to the end of the floats).  I have always wanted the bunks to come as close to the transom as possible.

Now having said that, it is based on info when I had my first boat 25 years ago.  Back then there were reports of people developing a "hook" in the transom if the bunks were too short (not specifically Malibu, but in general).  Boat building has advanced a lot since then I am sure, and I don't know if that same concern still holds true.  Regardless, I have always ordered bunks that were long enough to reach the transom or at least within a inch or two.

At a minimum, I would want the bunks to extend to, or beyond, the rear motor mount.  That can be measured and give an idea of what margin may exist.

Edited June 26, 2022 by familyfun

[hethj7]

Good info.  I will ask the lift dealer about this.  

[hethj7]

To close the loop, my lift dealer responded.   They state the recommended setting (I'm not sure whose recommendation) is the back of the transom sits 1-2' from the bunk.    They don't go to the 16' length until they get into longer 27-28' boats (they especially noted larger  double decker pontoons are a concern, which I would guess the toons stress easier under the added loads than the stringers on our inboards).    I'll sleep easy as if it was a prevalent issue with the hull, our lake would be flooded with complaints.   

 

I may check where the rear motor mount is, just out of curiosity.  Visualizing the space between the transom and motor, I would guess my motor mounts are probably still located over the bunks.  

 

[dalt1]

How hard would  it be to just change out to longer bunk boards? That's what I would do if pressuring dealer didn't get it done.

[hethj7]

I didn't pressure the dealer, I just asked about their thoughts and standard practice.  I'm sure the changeout isn't terrible, but it would be new angle bracing, etc.    I'm personally fine with how it is and don't see a reason to spend additional time or money chasing what seems to be a non-issue.   Whether a 21, 23, or a 25 LSV, the back position of the boat on all these lifts are set largely on how far you pull in before you can't clear the prop, so all the models probably have a bit of an overhang.   There are likely hundreds, if not thousands, of Malibu's and other inboards sitting just like mine.   

[G Spot]

I'd be careful about extending the bunks beyond the prop. You have to be very careful to not engage the prop because it can hit the bunk. 

Also, the further the bunk gets beyond the mount, the more it will flex and not provide the support you are seeking.

[familyfun]

I certainty have no data suggesting if it is an issue or not.  Even if it was an issue, it probably would not manifest until some number of years (if ever).  Having said that, my personal opinion is that dealer response sounds like it is more geared to justifying providing a lower cost more competitive product, then a higher cost configuration with the most margin.  But who knows. 

Before I upgraded our lift for the new 2022 25 LSV, I looked around our lake to see what other people did (with various brands of floating lifts).  Admittedly, I looked at a very small sample of 25 LSVs, G23s, and one Paragon (4 total I think) and they all had the bunks very close, or in one or two cases, just beyond the transom.  That, coupled with my previous research many years ago, prompted me to go with the 16 footers.  There could be thousands of boats sitting 1-2 feet beyond the bunks, I certainty don't know. Given the lack of any real data, it probably just comes down to personal comfort levels.  I personally have always preferred to over design (not limited to boat lifts).

[familyfun]

7 minutes ago, G Spot said:

I'd be careful about extending the bunks beyond the prop. You have to be very careful to not engage the prop because it can hit the bunk. 

Also, the further the bunk gets beyond the mount, the more it will flex and not provide the support you are seeking.

Very true.  Yea, we push our boat out a few feet before we engage the prop for just this reason (and coast in at the end when docking).  Maybe that why a dealer might recommend shorter bunks.  Maybe they get complaints of prop hits.

[justgary]

On 6/28/2022 at 4:32 PM, G Spot said:

Also, the further the bunk gets beyond the mount, the more it will flex and not provide the support you are seeking.

But surely it will provide more support than no bunk at all.  Trailer and lift manufacturers around here are using 4x8 juniper bunks stood the tall way, and they don't really flex under the boat.

Good loading guides can keep the boat from misaligning with the lift frame, and only lowering the lift enough to float the boat can keep the bunks out of the prop.

[G Spot]

On 6/30/2022 at 9:05 AM, justgary said:

But surely it will provide more support than no bunk at all.  Trailer and lift manufacturers around here are using 4x8 juniper bunks stood the tall way, and they don't really flex under the boat.

Good loading guides can keep the boat from misaligning with the lift frame, and only lowering the lift enough to float the boat can keep the bunks out of the prop.

Seems like the float lifts around here only use 2x6s, like a boat trailer. 4x8 would be much more rigid, I agree.

[EchelonMike]

Looking at my 6600# Hydrohoist for my 2008 247, the end of the bunks for me end at least a few feet from the transom, and end in front of the propeller.  There's no way a side to side swing would allow me to make contact with the propeller on the bunk or hoist mechanism, which I like a lot.  I installed a large pad to protect the bow of the boat in the slip, and before I raise it, I actually pull the boat forward so the bow is over the front edge of the dock deck, then raise it.  This gives me a very centered looking support of the entire boat from bow to stern.

[rjohn]

Thank you all for the feedback.  Glad to know their is margin!