Dingy Lifting Straps

[FWT]

Improve on my plan if you can.

Helmsman 38 is the mother ship, on order with delivery expected next spring. I'll be keeping the dingy up top, with a Jackson low profile davit crane installed.

The dingy and motor have been purchased, and absent the mother ship now just sits in my garage. ePropulsion Spirit 3hp will not be kept on the dingy, but rather will be stowed elsewhere and installed as used. The dingy is the Polycraft 10 ft. hard dingy, selected for its stability. Its heavy at 235lbs empty, but that's about the weight of a rib plus motor for popular models of both when the engine is left attached, which of course is the common choice. I'm planning to go with Soft Chocks at least initially. Following is a link to the dink that contains pics.

https://www.polycraft.com/300-tuffy

There are no installed lifting eyes. And frankly no good option to install them. Though the dealer advises one can use the handles (2 per side), and / or a similar towing point at the point of the bow at the top of the bowstem, from the start that seemed a bit less secure than I'd like. Probably OK. Safer to go another route.

So my plan is to use lifting straps that circle under the boat, thread them under the handles to a central ring or heavy shackle the crane hook can then lift. Two straps, 4 ends brought to a central ring. Use snap shackles at the ends of the straps for speed and ease, to attach to the ring. Threaded under the handles solves any risk of the straps sliding into an unbalanced condition.

Looking at the load numbers, its astonishing just how much more load straps can handle compared to fairly heavy lines.

I'm wondering if the addition of a lifting bar / spreader bar would be needed or useful? Or just another piece of gear to deal with? The advantage, if any, would seem to be to keep the load on the straps vertical. With straps threaded under the handles I can't see it doing much to mitigate slipping of the straps.

Its my best guess that the location of those handles is pretty good for weight distribution. Its definitely heavier at the stern, so those handles fairly far aft make sense. And the forward handles are at a point of a pretty good guess of the load balance of the weight forward of the rear strap. If used, the spreader bar would be 3-4 ft, and most likely 3 ft. If used, each pair of straps would terminate at an end of the bar, and then attach the bar to the crane hook at the center of the bar.

Thoughts?

 

[mvweebles]

Improve on my plan if you can.

Helmsman 38 is the mother ship, on order with delivery expected next spring. I'll be keeping the dingy up top, with a Jackson low profile davit crane installed.

The dingy and motor have been purchased, and absent the mother ship now just sits in my garage. ePropulsion Spirit 3hp will not be kept on the dingy, but rather will be stowed elsewhere and installed as used. The dingy is the Polycraft 10 ft. hard dingy, selected for its stability. Its heavy at 235lbs empty, but that's about the weight of a rib plus motor for popular models of both when the engine is left attached, which of course is the common choice. I'm planning to go with Soft Chocks at least initially. Following is a link to the dink that contains pics.

https://www.polycraft.com/300-tuffy

There are no installed lifting eyes. And frankly no good option to install them. Though the dealer advises one can use the handles (2 per side), and / or a similar towing point at the point of the bow at the top of the bowstem, from the start that seemed a bit less secure than I'd like. Probably OK. Safer to go another route.

So my plan is to use lifting straps that circle under the boat, thread them under the handles to a central ring or heavy shackle the crane hook can then lift. Two straps, 4 ends brought to a central ring. Use snap shackles at the ends of the straps for speed and ease, to attach to the ring. Threaded under the handles solves any risk of the straps sliding into an unbalanced condition.

Looking at the load numbers, its astonishing just how much more load straps can handle compared to fairly heavy lines.

I'm wondering if the addition of a lifting bar / spreader bar would be needed or useful? Or just another piece of gear to deal with? The advantage, if any, would seem to be to keep the load on the straps vertical. With straps threaded under the handles I can't see it doing much to mitigate slipping of the straps.

Its my best guess that the location of those handles is pretty good for weight distribution. Its definitely heavier at the stern, so those handles fairly far aft make sense. And the forward handles are at a point of a pretty good guess of the load balance of the weight forward of the rear strap. If used, the spreader bar would be 3-4 ft, and most likely 3 ft. If used, each pair of straps would terminate at an end of the bar, and then attach the bar to the crane hook at the center of the bar.

Thoughts?

I am about to go through a similar exercise to determine the length of each leg for a lifting bridle for my AB310AL, though it has four lifting eyes welded into the hull interior. Not sure how much it helps, but my plan is to use adjustable lashing straps (such as THESE from Harbor Freight) to get the balance right. From there, I can have a permanent bridle fabricated. Defender has a rigging shop that I'll probably use.

Given the way the handles capture the lifting straps, I don't think a spreader bar would help, and it might encourage the boat to rock for/aft more than if the bridle were just four legs.

I agree with you that using the handles for lifting might be a bridge too far for an extended lift. But the manufacturer might have a better point of view.

Looks like a cool little dink. I would have never thought about lifting eyes. As long as it's sitting in your garage and I'm sure you're itching to do anything to move the ball forward on your project, maybe grab a buddy, a six-pack of beer, and put a giant eyebolt in your garage ceiling and see how it goes. What could possibly go wrong?

Peter

 

[tiltrider1]

I don’t like the strap idea. I think there is to much potential for the boat slipping. This of course doesn’t mean it won’t work. I see no reason why you can’t put lifting eyes in your current choice of boat. All you would need to do is drill through the bottom of the boat and install a stainless steel backing plate. 3m 5200 would seal everything and then you could then safely hoist your dingy.

 

[FWT]

Thanks for that Peter.

I had my eye on something like this, with sewn in loops:

https://www.amazon.com/dp/B00I5HRMJ2/ref=sspa_dk_detail_1?psc=1&pf_rd_p=bff6e147-54ad-4be3-b4ea-ec19ea6167f7&pf_rd_r=CXCHBVB3QQGDRQ94QEN4&pd_rd_wg=mrxwp&pd_rd_w=JM20I&content-id=amzn1.sym.bff6e147-54ad-4be3-b4ea-ec19ea6167f7&pd_rd_r=a782c9f3-661a-433d-8c4d-790dd716fb0d&s=hi&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWwy&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUE0Qk5JVVBUQVBTMjAmZW5jcnlwdGVkSWQ9QTA4Nzg3MTcyWEdJS0NQMUdZMkFXJmVuY3J5cHRlZEFkSWQ9QTAyNjk4MzVZTTQ3V0hYTlgzRzcmd2lkZ2V0TmFtZT1zcF9kZXRhaWwyJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

And yeah, no question there is an itch to mess around with a boat I don't yet have. To do something to scratch the itch.

I finalized my plans on the electronics package last night and this morning.

But its more than that. When I start making lists of things to do to finish the job of squaring away things once the H38 arrives, its a LONG list. The more I can do ahead of time, the better.

 

[FWT]

I don’t like the strap idea. I think there is to much potential for the boat slipping. This of course doesn’t mean it won’t work. I see no reason why you can’t put lifting eyes in your current choice of boat. All you would need to do is drill through the bottom of the boat and install a stainless steel backing plate. 3m 5200 would seal everything and then you could then safely hoist your dingy.

Can't.

Look at the link to the dink. Its molded plastic. And essentially double walled, with hollow space between the sides and exterior, or floor and hull. Drilling holes in the BOTTOM of the boat isn't an appealing plan.

Hard for me to see how the straps will slip when held in place by the handles, but maybe I'm missing something?

 

[FWT]

Peter:

"Given the way the handles capture the lifting straps, I don't think a spreader bar would help, and it might encourage the boat to rock for/aft more than if the bridle were just four legs."

It took me a few minutes to really grasp that important point. The fore and aft pitching could well be big. Deal killer for the bar.

Thanks for pointing that out.

 

[mvweebles]

Thanks for that Peter.



I had my eye on something like this, with sewn in loops:



https://www.amazon.com/dp/B00I5HRMJ...jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==.

I started to look at stuff like that too. For this one though, I'd go to Sailrite. Here's a link to seatbelt webbing that has a 6700 lb breaking strength and is UV stable. If you have a sewing machine (or can borrow one), you could make this up in an hour or so. Just make sure you get UV stable thread to go with it.

https://www.sailrite.com/2-Yellow-Polyester-Seat-Belt-Webbing

Also comes in dyneema, which is overkill for your application.

I urge you not to give up on hanging in the garage with a buddy and a cooler of adult beverage. Proves that guys really don't mature past age 14 or so. We just polish our game a bit.

Peter

 

[FWT]

I started to look at stuff like that too. For this one though, I'd go to Sailrite. Here's a link to seatbelt webbing that has a 6700 lb breaking strength and is UV stable. If you have a sewing machine (or can borrow one), you could make this up in an hour or so. Just make sure you get UV stable thread to go with it.

https://www.sailrite.com/2-Yellow-Polyester-Seat-Belt-Webbing

Also comes in dyneema, which is overkill for your application.

I urge you not to give up on hanging in the garage with a buddy and a cooler of adult beverage. Proves that guys really don't mature past age 14 or so. We just polish our game a bit.

Peter

Thanks. The straps were not a particular selection, merely showing a selection with loop ends. I guess I could go with blank strap ends, and find the hardware to install metal ends, some clips (or whatever you call those gadgets you thread straps through) behind them, and make each strap adjustable in length. Nope, no sewing machine in the house.

The garage in the house where the dink now sits isn't a practical spot to organize a hanging party. It would take more work to organize the hanging than to rig the dink, and ladders taller than I own to rig it from the ceiling. My other house that has the perfect garage is 4 states away. I have a mismatch of garage and dink location.

Of course, a cooler of beer while guys sit around and stare at it and pitch ideas is always an option. We might not remember any of them, however.

 

[mvweebles]

Two critical questions

1. What's your plan for a cradle for deck mount and fastening? Might be possible to use lifting straps as double purpose to secure the boat to deck. Attached pic is a D-ring from Sailrite that would easily accept a carabiner

2. What color did you go with? Taxi-cab yellow is super cool, but I could live with lime green.

Peter
View attachment 131784

 

[FWT]

Two critical questions

1. What's your plan for a cradle for deck mount and fastening? Might be possible to use lifting straps as double purpose to secure the boat to deck. Attached pic is a D-ring from Sailrite that would easily accept a carabiner

2. What color did you go with? Taxi-cab yellow is super cool, but I could live with lime green.

Peter
View attachment 131784

Cradle: Going with Soft Chocks, at least to start. I can mess with just how I want it located without drilling holes in the deck only to find I wished I'd done something a bit different. I can take my time being fussy with it. And, its surrounded by enough rails to tie it down I should be OK on that score. Eventually I'll likely want to install some recessed / folding D rings for tie-down.

Retaining flexibility is part the awareness I don't KNOW this dingy from experience. I'm happy with what I see in the garage and stepping aboard one at a dock. But if in use I get unhappy with it, I don't have screwed in chocks selected for this dink to have to un-install.

Color: I went with Gull Grey, the lightest grey. These boats are poly, not fiberglass. No compounding and wax. Which also means they can show dirt and dark scuff marks. White will show that the most, but the darker you go the hotter they get on the seat of your pants. So Gull was the lightest non-white. After the purchase was made I stumbled by accident into a Facebook user group, and Gull was the concensus go-to color, but I just got lucky I guess with that pick. You can clean up a bad patch with fine grit paper, then hit it with a heat gun to shine it back up, but I don't think one would want to do that often or casually. Deeper gouges can be repaired with poly cord material you melt with a gun, smooth into the spot, sand it smooth, and then again hit it with a heat gun for shine.

 

[DNT99611]

You can get straps made for lifting with eyes in both ends from places like McMasterCarr. They will be longer than one thinks. Use a piece of line to run under the hull and up to the lifting point to get a measurement.

 

[FWT]

Thanks. And there seems to be a lot of sources for straps that focus on truckers.

 

[mvweebles]

I'll look forward to seeing what you end up with. I would think the challenge with off-shelf (vs bespoke) would be length to fit snugly under the crane boom.

This has been helpful for me. As mentioned, I'll be going through a similar exercise shortly, though I have four lifting eyes. I think I'll use 1-inch tubular webbing - has 4100 lb breaking strength. Two lengths sewn onto a large lift-ring with appropriately sized carabiner shackles to attach to dinghy. Lightweight, string, abrasion resistant, and UV stable.

https://www.sailrite.com/1-White-Polyester-Tubular-Webbing

Good luck and thanks for posting.

Peter

 

[Bmarler]

I think the rigging straps with built in loops are a simple option. I’d rig a three point lift. Two rigging straps through the rear handles, loops on the lifting eye. (Or shackle if the eye is too small.) third point to the bow position. Use a high quality adjustable strap to balance position of the bow. Seems pretty simple.
Those handles are designed to hold the weight of the dink, I’d use them with confidence.

 

[FWT]

I think the rigging straps with built in loops are a simple option. I’d rig a three point lift. Two rigging straps through the rear handles, loops on the lifting eye. (Or shackle if the eye is too small.) third point to the bow position. Use a high quality adjustable strap to balance position of the bow. Seems pretty simple.
Those handles are designed to hold the weight of the dink, I’d use them with confidence.

Curious if you are familiar with that dingy or making an assumption about handle strength?

 

[rslifkin]

Curious if you are familiar with that dingy or making an assumption about handle strength?

As long as you're not lifting the dinghy with a bunch of added weight (engine might be a concern), I'd agree with the logic that built in carrying handles are strong enough to lift the thing (as they expect you to pick it up by the handles).

 

[FWT]

The odds are you are right. The cost of being wrong could be huge to anyone below if 235 lbs gets loose.

 

[rslifkin]

The odds are you are right. The cost of being wrong could be huge to anyone below if 235 lbs gets loose.

It's one of those cases where I'd definitely want to monitor for signs of fatigue or issues over time. And I wouldn't hang a dinghy in davits by the lifting handles. But to lift and place on deck I'd consider it within the expected use of the handles.

 

[psneeld]

Lifting handles my not be designed for dynamic forces.

I too would be tempted but would have to give them a good eyeballing first to even consider.

 

[DCDC]

I recently built a lift harness for a new dinghy with a similar crane height and a stern rail to clear:

Dinghy is a AB 11.5 aluminum RIB with 25hp outboard and battery. With full tank and all the extra stuff probably weighs close to 450 lbs. It has eyes on the frame for lift points slightly above the waterline. I made the four-leg harness out of vinyl covered SS lifeline cable with SS thimbles and hand crimped sleeves.

The challenge was to obtain the best vertical harness height. Given the available lift height, keel depth, lift hook/weight, and the need to lift over a rail there wasn’t a lot of remaining height left. In your case the height of the handles will further reduce clearance. Maybe not a problem if your lift extension is higher.

The first setup worked well until a gust of wind flipped the dinghy around the fore and aft axis. Scary but it stayed connected and we managed to flip it back. Battery and gas tank were tied down to wood mounts glued to the hull with Loctite polyurethane adhesive and thankfully stayed in place. The lift ring on the harness was too close to the dinghy’s COG so it didn’t take much force for it to pivot. Added a few inches to the harness height for stability. Acceptable but it rubs along the top rail when swinging it in or out and we are apprehensive of lifting with winds above 20 knots.

Good luck with your lift system!

 

[mvweebles]

The odds are you are right. The cost of being wrong could be huge to anyone below if 235 lbs gets loose.

My thinking too. Would definitely talk to the manufacturer before using them as lifting points. It's one thing to drag up a beach. Another thing altogether to have it 15 feet on the air on a gusty day. The kicker would be one would break, then send the dinghy wildly swinging. It would not just drop down. Would be a kamikaze spiral.

That said, I wouldn't be surprised if the handles are beefed-up to serve as proxy for lifting points or tie-down points. No way to tell without talking to manufacturer.

Peter.

 

[FWT]

DCDC:

Thanks for that. I am indeed "worried" for lack of a better word about the vertical height. But the COG issue isn't one I thought of. Since no matter what on my dingy, the center lift ring has to be above the side rail I think I'm OK on that one. Thank heavens, because I sure don't want to experience that sort of flip in mid-air.

Flip or no flip, a lift in 20 kts would not be much fun.

But back to height. I doubt I'll arrive at a satisfactory answer on how much I have to play with, before I have the mother ship. So the more I think this through (with everyone's help), the more I think that on Day1 I'll either be prepared to do something temporary, or if more ambitious get straps organized to be adjustable. And just play with it in real time.

 

[FWT]

My thinking too. Would definitely talk to the manufacturer before using them as lifting points. It's one thing to drag up a beach. Another thing altogether to have it 15 feet on the air on a gusty day. The kicker would be one would break, then send the dinghy wildly swinging. It would not just drop down. Would be a kamikaze spiral.

That said, I wouldn't be surprised if the handles are beefed-up to serve as proxy for lifting points or tie-down points. No way to tell without talking to manufacturer.

Peter.

Thanks

In one sense, there's nothing to be gained by lifting from the handles since if threading lines under it would keep the angles to the central ring almost the same.

Of course, using the handles would save the task of getting the straps under the boat.

This dingy is pretty new to the US. Most buyers use it for shallow water fishing, not as a tender. With not many around I have yet to find an owner with lift experience, to pick their brain. There is one video out there of it used as a tender on a rather large boat, with the cradle on a rather large swing platform. That's not a comparable situation for me.

 

[thataway]

I have found with dinghies and lifting with a davit, both a side to side spreader bar, and longitudinal spreader bar worked to keep the length of the bridle down to a manageable distance. This works even with a single point lift forward. The for and aft bar allows precise location of the lifting point. For small boats, a piece of square aluminum tubing, and inserting a wooden dowel with epoxy to secure it in place works well. Drill for eye bolts when then proper balance point (points, if you are going to leave a fuel tank, motor or battery in the boat at times.). I have used this system with dinghies up to about 200#. There are many other ways, in aluminum or SS with two L brackets , to make these types of spreader bars for heavier boats--and then can save several feet of bridle length; enough to lift over railings easily.

These polypropylene boats are almost indestructible. Think of the ubiquitous "Sport Yak" which someone coined the phrase, so ugly no one would want to steal it (does not apply to this mentioned dinghy), and so indestructible that you cannot get rid of it. Several of these ran the entire Grand Canyon from Lee's ferry to Lake Meade (with modification for better oars).

 

[henrymei]

If the handles aren’t reliable lifting points per the manufacturer, I’d consider reevaluating your choice of tender. Trying to thread a sling under the dinghy will probably be a pain if you use it with any regularity. In fresh conditions it might be close to impossible. Full disclosure: I am biased towards aft mounted dinghies. We have dogs and love being able to quickly raise and lower our tender on a hydraulic lift. Good luck with your project. Please post your solution.

 

[mvweebles]

I have found with dinghies and lifting with a davit, both a side to side spreader bar, and longitudinal spreader bar worked to keep the length of the bridle down to a manageable distance. This works even with a single point lift forward. The for and aft bar allows precise location of the lifting point. For small boats, a piece of square aluminum tubing, and inserting a wooden dowel with epoxy to secure it in place works well. Drill for eye bolts when then proper balance point (points, if you are going to leave a fuel tank, motor or battery in the boat at times.). I have used this system with dinghies up to about 200#. There are many other ways, in aluminum or SS with two L brackets , to make these types of spreader bars for heavier boats--and then can save several feet of bridle length; enough to lift over railings easily.

These polypropylene boats are almost indestructible. Think of the ubiquitous "Sport Yak" which someone coined the phrase, so ugly no one would want to steal it (does not apply to this mentioned dinghy), and so indestructible that you cannot get rid of it. Several of these ran the entire Grand Canyon from Lee's ferry to Lake Meade (with modification for better oars).

Spreader bars to reduce vertical height of harness is an interesting idea. My dink has 4 lifting points so an H-frame with an aluminum T-bar longitudinally and two short L-angle bars crosswise. Could drill several holes in the main longitudinal bar to easily adjust for balance. I still would think it would rock fore/aft fairly easily, but worth a try.

OnlineMetals.com has a great assortment of stainless and aluminum metals. Shipping isn't awful either.

Peter

 

[FWT]

I have found with dinghies and lifting with a davit, both a side to side spreader bar, and longitudinal spreader bar worked to keep the length of the bridle down to a manageable distance. This works even with a single point lift forward. The for and aft bar allows precise location of the lifting point. For small boats, a piece of square aluminum tubing, and inserting a wooden dowel with epoxy to secure it in place works well. Drill for eye bolts when then proper balance point (points, if you are going to leave a fuel tank, motor or battery in the boat at times.). I have used this system with dinghies up to about 200#. There are many other ways, in aluminum or SS with two L brackets , to make these types of spreader bars for heavier boats--and then can save several feet of bridle length; enough to lift over railings easily.

These polypropylene boats are almost indestructible. Think of the ubiquitous "Sport Yak" which someone coined the phrase, so ugly no one would want to steal it (does not apply to this mentioned dinghy), and so indestructible that you cannot get rid of it. Several of these ran the entire Grand Canyon from Lee's ferry to Lake Meade (with modification for better oars).

Thanks for that thoughtful answer.

I can't KNOW for sure what will and won't work until the mothership on order arrives next spring.

That H frame lifting bar arrangement would certainly keep any vertical height challenges at bay. What I am coming to THINK the case is, that I can't go crazy using up a lot of vertical height, but that I'll have "enough" to play with.

But, your H frame idea may well become a go-to for a Plan B if needed.

So thanks for that.

 

[FWT]

If the handles aren’t reliable lifting points per the manufacturer, I’d consider reevaluating your choice of tender. Trying to thread a sling under the dinghy will probably be a pain if you use it with any regularity. In fresh conditions it might be close to impossible. Full disclosure: I am biased towards aft mounted dinghies. We have dogs and love being able to quickly raise and lower our tender on a hydraulic lift. Good luck with your project. Please post your solution.

There are a bunch of reasons why I won't be going on a path of hanging the dingy off the swim platform.

But your point about running the straps under it getting old may well be the experience. It gave me pause in considering it. We'll just have to see.

Installation of lift eyes would solve a lot, if it were possible. But the specifics of that present challenges I doubt can be solved in a satisfactory way. I plan to investigate this path more.

 

[koliver]

Installation of lift eyes would solve a lot, if it were possible. But the specifics of that present challenges I doubt can be solved in a satisfactory way. I plan to investigate this path more.

I have a pair of kayaks made in ABS plastic. I hung one from its lifting handles for a short while and it pulled the lifting handle attachment out of the kayak. I have looked at a repair and abandoned the task, as I don't have access adequate to get inside and anything done from just accessing the outside would not answer at all. Luckily the kayaks live on the boat, so the handle at the stern never gets touched.

 

[FWT]

I have a pair of kayaks made in ABS plastic. I hung one from its lifting handles for a short while and it pulled the lifting handle attachment out of the kayak. I have looked at a repair and abandoned the task, as I don't have access adequate to get inside and anything done from just accessing the outside would not answer at all. Luckily the kayaks live on the boat, so the handle at the stern never gets touched.

No way would I attempt to leave this particular boat suspended from the side carry handles. I question them for the loads in a lift. The shock loads from being left suspended would be out of the question as far as I am concerned.

So yeah, I don't know your boat, but I sure get what you are saying.

I have serious doubts lift eyes can be "welded" to the poly material sufficiently strong to do the job. But if anyone has info on that, I'm interested.

And I am even more sure lag bolting eyes into the wall of it would not work. There is a small cleat on the bow, screwed into the wall. I've heard reports some tried to tow the dink using that cleat in an earlier model and just ripped the cleat out. The later model, my model, has a smaller version of the lift handles on the bow now, to be used for towing and pulling onto a trailer.