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 How much can transom overhang boat lift?
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Chesagansett

RO# 9880



Posted - Dec 18 2016 :  22:46:28  Show Profile  Reply with Quote
I'm considering the purchase of a center console boat that is a little bit long for my dock/boat slip / boat lift. The transom of this boat would end up being about 3.5 feet rear of the boat lift's rear cross-beam. The lift's bunks extend 1.5 feet rearward of the lift's rear cross-beam. So, the boat transom would overhang the end of the bunks by a total of about 2 feet.

Two questions: 1.) Is this too much of an overhang, considering the boat would have a pair of 562-pound outboards hanging off the transom? 2.) If that's too much overhanging weight, can this issue be solved simply by replacing the lift bunks with longer bunks that would extend farther rearward? To me, it seems that would work as far as supporting the boat. The one negative is that no matter what, it would put more weight on the rear beam, so I might need to beef up the rear cables with heavier cables to support the extra weight.

There is no issue for the lift motors, as they already are overkill for that lift. Note: There is no issue with the boat sticking out into a fairway or anything like that. This is on a canal behind my house, and the dock/slip/lift roughly parallels the seawall. I have an 80' sea wall, so plenty of room. Just not thought out well for size and positioning, etc. As this dock is approaching 18 years old, eventually I'll probably rebuild the dock / slip / lift so that it is better arranged.

Thanks for any thoughts, input, replies, etc.

Glenn
Cape Coral, FL
Four Winns Sundowner 245

Edited by - Chesagansett on Dec 18 2016 22:52:39

Homeport: Cape Coral, FL

Radioactive

RO# 3238



Posted - Dec 18 2016 :  22:53:08  Show Profile  Reply with Quote
a) Boat should be fully supported. If you have an overhang, over time, the hull is likely to develop a "hook", which you definitely do not want.

b) While simply "beefing up" the rear might work, the right way is to re-position the lifting array so that the load is properly balanced.

----

At this point, ask a pro, which I am not.




Bill

"No matter where you go, there you are." -- Buckaroo Bonzai
"There is nothing, absolutely nothing, half so much worth doing as simply messing about in boats." - Kenneth Grahame

Homeport: MS Gulf Coast Go to Top of Page

Padraig

RO# 4792

Posted - Dec 18 2016 :  23:20:15  Show Profile  Reply with Quote
Zero

Padraig

Homeport: Western NY Go to Top of Page

jtybt15

RO# 3300



Posted - Dec 19 2016 :  01:41:47  Show Profile  Reply with Quote
Is there a way to load the boat stern first? That way, up to 1/4 of the bow overhanging shouldn't be a problem.




Charlie

There is much to be said, in a world like ours, for taking the world as you find it and fishing with a worm.-Bliss Perry, 1904



Homeport: Ca Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 19 2016 :  03:45:04  Show Profile  Reply with Quote
quote:
Originally posted by jtybt15

Is there a way to load the boat stern first? That way, up to 1/4 of the bow overhanging shouldn't be a problem.




That was a thought I had considered, but there are a couple hindrances to that. The boat has a big bow flair with a beam of 9'8" at it's widest. The beam is several inches less toward the rear. I have 10 feet of width between the insides of my pilings, but my lift motors stick inward of the pilings, giving me only about 9'6" between the motors which are mounted on the rear pilings. If I go in stern first, the beamier front part of the boat will be wider than the width between the lift motors, and it will limit how high I can lift the boat without it bumping up into the lift motors. It would work most times, but if there was a particularly high tide with some surge, I wouldn't be able to lift the boat high enough without that beamy area of the boat hitting the bottoms of the lift motors. If I go in the traditional bow first, the narrower rear third of the boat would be able to fit between the motors, and I would be able to lift the boat plenty high enough when needed. Yup, I measured that boat's beam carefully along that rearward area after I noticed that it was less beamy back there, and thought it might fit between the lift motors when boat is raised. The measurements confirmed my thought.

Even if space was not an issue, going in stern first is a PITA. Have to raise the motors each time to get the motors past the cross beams, etc. Then lower motors to flush them. Then raise them again next time you want to leave lift/slip. Then lower them again to take off. Lather, rinse, and repeat every time you want to leave and return to slip / boat lift.



Glenn
Cape Coral, FL
Four Winns Sundowner 245

Edited by - Chesagansett on Dec 19 2016 04:02:51

Homeport: Cape Coral, FL Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 19 2016 :  03:57:01  Show Profile  Reply with Quote
quote:
Originally posted by Radioactive

a) Boat should be fully supported. If you have an overhang, over time, the hull is likely to develop a "hook", which you definitely do not want.

b) While simply "beefing up" the rear might work, the right way is to re-position the lifting array so that the load is properly balanced.

----

At this point, ask a pro, which I am not.







Yup, my next move is to get the lift company over here before I do anything regarding the boat purchase. If it's just not going to work without major dock re-construction, I'm going to hold off on the bigger boat purchase and stick with my 25' cuddy until I do something with the dock.

Thanks.




Glenn
Cape Coral, FL
Four Winns Sundowner 245

Homeport: Cape Coral, FL Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 19 2016 :  19:28:54  Show Profile  Reply with Quote

Well, today I went straight to the source. I drove over to the office of the company that installed my lift (long before I moved here) which is one of the biggest, if not the biggest, lift installer in the region.

What I somewhat suspected, but did not mention here earlier, was confirmed by the lift company. "The boat will develop a hook" is an old wive's tale (old mariner's tale?) that refuses to die. I was more worried about needing heavier cables in the rear than I was about a "hook". I recently looked around at many of the the 24'-30' boats in the canals around here that are supported with 14 foot and occasionally 16-foot long bunks. The lift guy says that for the 28' boat I am considering, it would be reasonable to have it overhand the rear cross beam by 3.5 to 4 feet, which would overhang the end of the bunks by about 2 feet. The front and rear cross beams are separated by only 11 feet, so it would overhang the front cross beam by about 13 feet and the bunks by about 11.5'. The current bunks are 14 feet long, so there is 1.5 feet of bunk past each cross beam. He said most boats' transoms do overhang the bunks by a foot or two, and are fine. The bows of many of the boats hang over the bunks by 10-12+ feet. Sure, there are not motors on the bow, but compare 12 feet of a "lever" of all that fiberglass weight versus 1.5 to 2 feet of lever with the motors. He said that having a 28' boat sit about 3.5 to 4 feet rearward of the rear crossbeam should roughly balance it out equal to the 12.5 to 13 feet of bow forward of the front crossbeam.

I do need to re-do my bunks soon, so I will likely order 16-foot bunks to be "extra sure" if I buy this 28' boat. I also am due for cables, so will upgrade from 1/4" to 5/16" which will increase capacity from 8.K to 10K, for "added insurance".

That was a relief today to learn that this will work.

Thanks all.




Glenn
Cape Coral, FL
Four Winns Sundowner 245

Homeport: Cape Coral, FL Go to Top of Page

smitty477

RO# 31913



Posted - Dec 20 2016 :  13:43:03  Show Profile  Reply with Quote
"What I somewhat suspected, but did not mention here earlier, was confirmed by the lift company. "The boat will develop a hook" is an old wive's tale (old mariner's tale?) that refuses to die. I was more worried about needing heavier cables in the rear than I was about a "hook". I recently looked around at many of the the 24'-30' boats in the canals around here that are supported with 14 foot and occasionally 16-foot long bunks. The lift guy says that for the 28' boat I am considering, it would be reasonable to have it overhand the rear cross beam by 3.5 to 4 feet, which would overhang the end of the bunks by about 2 feet"


IMO - this is a poor answer and from the wrong source(s) to protect the investment you have in your soon to be new boat.
I have recently been shopping for a boat that would seem to be very similar to the one you have described. A larger 'trailerable' boat with larger twin outboards and have visited a number of boat manufacturers as well as trailer distributors.
All of them want the transom of the boat to be supported or at least in close proximity to a bunk support (maybe within a few inches max).
Now this is coming from the boat builders as well as the bunk trailer manufacturers I have spoken to - most of the trailer sites have 'guides' online that show this is required.
I would ask that you get some good answers from folks that are concerned only about the boat and leave the lift design and capability to the lift folks.
Good luck with the new boat and lift whatever you end up with...



Homeport: NY Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 20 2016 :  14:54:47  Show Profile  Reply with Quote
smitty477 - Thanks for the reply. When I replace the bunks, I am going to get the longer bunks so that there will be minimal overhang at the transom end. No matter the bunk length, it will still have just as much weight on the rear cross beam, so will be upgrading the cables, as well. I'll still have a lot of overhanging length forward of the front cross beam, as does every boat on a lift around here does. Not much I can do on that. These 10,000 pound lifts are done in a 10x10 or 10x11 box pattern of the main and cross beams, with 14-16' bunks, and there aren't any boats that short that are 10K pounds, ... so they do count on some overhang ... at least up front.

Boat trailers are a slightly different animal, as you don't have a static load. It can be bouncy, and they have potential shifting loads to worry about, as well.

I might try to call the boat manufacturer to see what their opinion is for static load lift storage. I do plan to get a trailer, as well, which as you indcated should be supported most of the way.

Thanks for the reply. Much appreciated. If I get a response from the manufacturer, I'll let y'all know how it went.








Glenn
Cape Coral, FL
Four Winns Sundowner 245

Edited by - Chesagansett on Dec 20 2016 14:57:50

Homeport: Cape Coral, FL Go to Top of Page

Sandy

RO# 1159

Posted - Dec 21 2016 :  01:24:28  Show Profile  Reply with Quote
I wouldn't trust anything else said by someone who claims it is an "old wives' tale" that an unsupported stern section/transom with at least 1124 lbs of (dry?) motor weight can develop a hook. If you've ever ridden in a very wet boat which had developed a hook you would not be so trusting. And it doesn't just pop back out later once the boat is properly supported.

Sandy

Homeport: The Vineyard Go to Top of Page

missnmountains

RO# 22737

Posted - Dec 21 2016 :  09:28:52  Show Profile  Reply with Quote
There are boats all over south Florida including here in Cape Coral that are close to 50,000 pounds that are on lifts. Quite a bit of the boat is off the bunks. I have never seen a boat develop a "hook" while on a lift. It is interesting because most of the boats don't come off their lifts but a couple times a year.

There is one owned by a high end builder here in town that is 44,000 pounds. He lives on the river. Take a look at it. I bet 20 feet of the boat hangs off the lift.

Ken


2008 58 Sedan Bridge

Homeport: Cape Coral, FL Go to Top of Page

smitty477

RO# 31913



Posted - Dec 21 2016 :  09:40:07  Show Profile  Reply with Quote
"I might try to call the boat manufacturer to see what their opinion is for static load lift storage. I do plan to get a trailer, as well, which as you indcated should be supported most of the way.

Thanks for the reply. Much appreciated. If I get a response from the manufacturer, I'll let y'all know how it went."

M future plans include a bunk trailer as well as a boat lift with a boat type similar to what you describe - about 26-29' with twin
outboards. I have spoken to a few trailer dealers and they said keep it within a few inches of the transom. One dealer supplied a good idea about easily finding the approx. 'tipping' point fwd and aft - he said just google pictures of your desired boat make a size with the words "on a trailer' following it. You will likely see many pics of the boat you are interested in with the location of the trailer wheels (2 or 3) indicating how far back the fore/aft weight center really is. On these twin engine boats of this size it is often within 1/4 the length near the stern with the bow itself having very little weight. Engines, fuel tanks, water weight, fish wells etc are all carried well aft with the lever arm for the outboards past the stern just adding to the mix.
So far I have also spoken to dealers of Robalo, Sea Swirl, and Hydra Sports boats which all say you really want to support the stern well. As much as the first 10' of the boat from the bow needs no support and some even further aft with no support.
Good luck with your search and new to you boat.....



Homeport: NY Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 21 2016 :  15:20:48  Show Profile  Reply with Quote

Thanks all for the replies. It does seem to make logical sense to support the boat as well as possible. On the other hand, as missnmountains indicates, there are tons of boats around that are only partially supported, and we just aren't seeing any accounts of "hooked" boats. Also, every boat lift manufacturer makes them so they only support a portion of the boat. It would seem that if this causes issues, there would be lots of backlash against lift manufacturers, and the market would force them to change design. That hasn't occurred. That being said, I'm still going to do the best I can to support the boat, and get longer bunks when they get replaced (soon). There will still be "some" overhang of the boat, but I probably won't lose much sleep over it, as most boats here do the same without issue.

Much thanks, all.



Glenn
Cape Coral, FL
Four Winns Sundowner 245

Homeport: Cape Coral, FL Go to Top of Page

Padraig

RO# 4792

Posted - Dec 23 2016 :  08:17:07  Show Profile  Reply with Quote
IMO, just get the longer bunks and redo the cables if needed.
You will sleep better.


Padraig

Edited by - Padraig on Dec 23 2016 18:24:42

Homeport: Western NY Go to Top of Page

Padraig

RO# 4792

Posted - Dec 23 2016 :  08:17:08  Show Profile  Reply with Quote
Duplicate

Padraig

Edited by - Padraig on Dec 23 2016 18:26:59

Homeport: Western NY Go to Top of Page

Veebyes

RO# 11224

Posted - Dec 23 2016 :  09:15:51  Show Profile  Reply with Quote
Not a lift user but very much a blocked dry storage guy. When supporting the two main things I consider are where the boats center of gravity is & making sure it is supported directly under strong points inside the hull such as engine stringers & bulkheads.

An OB will have its center of gravity well aft. My OB boat is supported almost right under the transom.



Homeport: Bermuda Go to Top of Page

pdecat

RO# 842



Posted - Dec 23 2016 :  15:59:07  Show Profile  Reply with Quote
I am very surprised and sceptical that FG boats can hook like Wood boats did.

I had several boats on lifts with 2-3' of overhang without problems however I didnt have 1000# of OBs on them. My concern was that the balance point not be anywhere near aft so that the boat was steady on the bunks.

I always backed into the lift because that gave me easy acess to the engine and drive leg. Raising the leg a little to clear the lift was not a bother.


Bruce



Homeport: Gulf Coast FL Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 23 2016 :  20:11:53  Show Profile  Reply with Quote
quote:
Originally posted by Padraig

IMO, just get the longer bunks and redo the cables if needed.
You will sleep better.




Yes, that is what I plan to do. Support as much as possible with longer bunks, and beef up the cables. Interestingly, I did more searches on this topic, and one of the searches that came up was a guy trying to support his Sea Ray. He quoted the Sea Ray manual saying that THE best way to support that boat is to craddle it at the sling points. The rear sling location mark was one-quarter of the way from the transom to the bow. Very interesting, as that would leave several feet of transom overhang, and it was suggested by the manufacturer themselves in a written statement in the manual. Here is a quote from that guy quoting the manual (this was from 2002):

His quote of Sea Ray's manual:
"A cradle is the ideal support for the boat whenever it is not in the water. Properly designed and constructed, it will provide support at the proper points, which is essential to avoid stress on the hull. Boat placement on the cradle should line up as closely as possible to the sling tags on the side of the deck. Do not rest the boat on underwater fittings."

Quote of guy who was inquiring about transom support:
<<<...."The picture shows the cradles (two) at roughly 1/4 and 2/3 the distance from transom to bow. Notably absent is any support under the transom."....>>

Interesting to ponder, as many boats in boat houses are stored in slings all year long, and the sling alignment marks are not at the transom, but several feet forward of there. I'm starting to believe the lift guy that it is an old wives tale, ... and am hearing lots of "hook" stories, but nobody has actually seen a hook in a modern fiberglass (not wood) boat, ... And everybody along the canals in the land of 1000s of boat lifts hasn't seen the problem, either. Has anyone here actually witnessed this themselves occurring to a modern fiberglass boat?

Thanks.


I;m still going to support mine as much as possible, but not lose a bit of sleep if I get it to within 6-inches of the end of the bunks.




Glenn
Cape Coral, FL
Four Winns Sundowner 245

Edited by - Chesagansett on Dec 23 2016 20:26:03

Homeport: Cape Coral, FL Go to Top of Page

Veebyes

RO# 11224

Posted - Dec 24 2016 :  19:07:30  Show Profile  Reply with Quote
Depends on the type of boat for where the slings/weight is supported. An OB needs support at or near the transom. The bulk of the weight of a straight IB is in the area of the engine. Typically not much weight aft.


Homeport: Bermuda Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 24 2016 :  23:00:24  Show Profile  Reply with Quote
quote:
Originally posted by Veebyes

Depends on the type of boat for where the slings/weight is supported. An OB needs support at or near the transom. The bulk of the weight of a straight IB is in the area of the engine. Typically not much weight aft.




Excellent point!




Glenn
Cape Coral, FL
Four Winns Sundowner 245

Homeport: Cape Coral, FL Go to Top of Page

mdoherty

RO# 12220



Posted - Dec 24 2016 :  23:15:12  Show Profile  Reply with Quote
When the boat is in the water the support is forward of the transom, what's the problem?

Mike

Homeport: Leesburg VA/Edgewater, MD Go to Top of Page

smitty477

RO# 31913



Posted - Dec 26 2016 :  15:32:42  Show Profile  Reply with Quote
"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.



Homeport: NY Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 26 2016 :  22:10:40  Show Profile  Reply with Quote
quote:
Originally posted by smitty477

"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.





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.




Glenn
Cape Coral, FL
Four Winns Sundowner 245

Edited by - Chesagansett on Dec 26 2016 22:11:49

Homeport: Cape Coral, FL Go to Top of Page

smitty477

RO# 31913



Posted - Dec 27 2016 :  15:43:42  Show Profile  Reply with Quote
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.

[/URL]




Edited by - smitty477 on Dec 27 2016 15:47:08

Homeport: NY Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 27 2016 :  18:29:34  Show Profile  Reply with Quote
"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.







Glenn
Cape Coral, FL
Four Winns Sundowner 245

Homeport: Cape Coral, FL Go to Top of Page

smitty477

RO# 31913



Posted - Dec 30 2016 :  12:18:54  Show Profile  Reply with Quote
"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.





Homeport: NY Go to Top of Page

froggy3k

RO# 4247

Posted - Dec 31 2016 :  09:09:17  Show Profile  Reply with Quote
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!



Homeport: Sunny SW FL Go to Top of Page

Chesagansett

RO# 9880



Posted - Dec 31 2016 :  16:22:42  Show Profile  Reply with Quote
quote:
Originally posted by froggy3k

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!



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.


Glenn
Cape Coral, FL
Four Winns Sundowner 245

Homeport: Cape Coral, FL Go to Top of Page
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