How much can transom overhang boat lift?
- Thread starter Chesagansett
- Start date
"Has anyone here actually witnessed this themselves occurring to a modern fiberglass boat?"
In my search of boats I have seen more than one which has hull issues due to the transom not being supported well near the stern on trailers. On any of my boats the boat is always supported at the stern - on higher powered outboards it is supported all the way to the stern nd in larger inboards the keel is supported as far back as practical and the hull at the very stern with at least two stands.
I would love to see some pictures of these boats not supported for 3-10' or more off they stern - If you have pics please post them. Perhaps others would buy a boat that was stored in this type of manner but it would not be a boat I would consider for myself or a friend.
In my search of boats I have seen more than one which has hull issues due to the transom not being supported well near the stern on trailers. On any of my boats the boat is always supported at the stern - on higher powered outboards it is supported all the way to the stern nd in larger inboards the keel is supported as far back as practical and the hull at the very stern with at least two stands.
I would love to see some pictures of these boats not supported for 3-10' or more off they stern - If you have pics please post them. Perhaps others would buy a boat that was stored in this type of manner but it would not be a boat I would consider for myself or a friend.
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Thanks smitty. Good info. As for boats overhanging bunks 3-10 feet, the 10 feet (or even more) is in the bow. For the sterns you see more like 3, maybe 4 feet on some. This is on lifts, not trailers. There are many mid-size boats on 14-16 foot bunks around here with some overhand in the stern, and more overhand in the bow.
I took the boat down the canal yesterday on the way to boat ramp I putit on trailer to be able to clean it better. I'm either trading it in, or putting it up for brokerage. Anyway, on the way down the canal, I pulled 0ut my cell phone to snap a couple photos. Not great quality photos, but they do show a bit of stern overhang.
This is a Bayliner that overhangs about 3.5 feet in the stern. You can see the end of the bunk an inch or two just to the right of the PVC guide pole, and probably about 3.5 to 4 feet short of the transom.
Here is a Glacier Bay catamaran that is not using bunks, and it looks like the sponsons (hulls) overhand the cross-beam by a foot or thereabout.
I'll try to get more pics next time I'm out on the water, but that likely won't be until around mid-January with the new boat. Maybe missnmountains or others in the area can snag a few photos while out on the canals.
Thanks smitty. Your input is appreciated, and I will be getting longer bunks.
We were back in Fla. this month searching for homes that will eventually have a lift for our boat as well. IMO and in our case at least the stern will be supported as suggested by the dealers we spoke with.
"As for boats overhanging bunks 3-10 feet, the 10 feet (or even more) is in the bow."
Based upon the title of this thread I would guess that we all agree we are only speaking about the stern and not the bow.
"This is on lifts, not trailers."
IMHO - I see not difference in the requirement to support a boats stern whether on a trailer, lift or in rack storage.
This is one of my last trailer boats with the bunks running all the way to the stern, as I have always practiced to protect the boats integrity.
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"As for boats overhanging bunks 3-10 feet, the 10 feet (or even more) is in the bow."
Based upon the title of this thread I would guess that we all agree we are only speaking about the stern and not the bow.
"This is on lifts, not trailers."
IMHO - I see not difference in the requirement to support a boats stern whether on a trailer, lift or in rack storage.
This is one of my last trailer boats with the bunks running all the way to the stern, as I have always practiced to protect the boats integrity.
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"This is on lifts, not trailers."
The only thing I can think of for it being more important on trailers is that it is an active, bouncy load .... but I'm not sure if that is the only reason.
The only thing I can think of for it being more important on trailers is that it is an active, bouncy load .... but I'm not sure if that is the only reason.
"When the boat is in the water the support is forward of the transom, what's the problem?"
Hello Mike,
I did not see this post until just now....
Perhaps an example of the loading of the boats hull with this comparison will help visualize what can/is happening to the hull material itself.
I am looking at a 29 foot boat with a bit over 10 foot beam that will weigh in at about 10,500 pounds when ready to run.
If that boats hull is in the water it will be supported by about 210 sq. feet of hull (about 30,240 sq inches)
If I put that boat on a set of bunks that are 3" wide by 20 feet long there will be about ten sq. feet (about 1,440 sq. inches)
That means my boat in the water will see about 50 pounds per square foot and on the bunks it will see about 1,050 pounds per square foot. The added problem of point loading caused by the bunks not being centered (for and aft tipping point) with the loaded weight will cause the loading to go up on some of the bunk area and down on other parts of the bunks. The further off you make the bunks from the centerline the more the load will be uneven on the bunks - a good guess would lead you to believe that some bunk areas will see twice that load even if they reach the back of the boat - about 2,000 lbs per square foot.
I know what happens when I take a sheet of 3/4 inch plywood and apply forces like that to it. And when their is no support for a 'couple of feet' on the plywood with loads in that range poor things happen very quickly.
Hello Mike,
I did not see this post until just now....
Perhaps an example of the loading of the boats hull with this comparison will help visualize what can/is happening to the hull material itself.
I am looking at a 29 foot boat with a bit over 10 foot beam that will weigh in at about 10,500 pounds when ready to run.
If that boats hull is in the water it will be supported by about 210 sq. feet of hull (about 30,240 sq inches)
If I put that boat on a set of bunks that are 3" wide by 20 feet long there will be about ten sq. feet (about 1,440 sq. inches)
That means my boat in the water will see about 50 pounds per square foot and on the bunks it will see about 1,050 pounds per square foot. The added problem of point loading caused by the bunks not being centered (for and aft tipping point) with the loaded weight will cause the loading to go up on some of the bunk area and down on other parts of the bunks. The further off you make the bunks from the centerline the more the load will be uneven on the bunks - a good guess would lead you to believe that some bunk areas will see twice that load even if they reach the back of the boat - about 2,000 lbs per square foot.
I know what happens when I take a sheet of 3/4 inch plywood and apply forces like that to it. And when their is no support for a 'couple of feet' on the plywood with loads in that range poor things happen very quickly.
Hey Chesagansett, can you ping me at Froggy3k at hotmail?
We are almost neighbors. I'm in Port Charlotte right off Charlotte Harbor but do work down your way in Ft Myers.
We are looking on up sizing our present boat to something like your Four Winns. Our lift is only a 4K at this time but shopping for a 10K to replace it with.
Happy new year from SWFLA!
We are almost neighbors. I'm in Port Charlotte right off Charlotte Harbor but do work down your way in Ft Myers.
We are looking on up sizing our present boat to something like your Four Winns. Our lift is only a 4K at this time but shopping for a 10K to replace it with.
Happy new year from SWFLA!
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Okay, will send off an e-mail to you. Not sure if you were looking to buy the Four Winns, but we already worked out a trade-in deal with the boat dealer. Look for email in a few minutes.