T&T: Boom electric winch/hoist

[Jim Gano via Trawlers-and-Trawlering]

I few weeks ago I started a thread about installing an electric boom winch/hoist on my 42 foot Grand Banks Classic to lift my 250 pound dingy/motor.  My boom hoist has a triple block arrangement (that is, the boom hoist line starts at the top of the mast, routes down to the end of the boom, back up (3 times) and then down parallel to the mast to a cleat at the base of the mast).  To raise the boom from a horizontal position to the up-angle position (about 35-40 degrees down from vertical) required to lift my dingy straight up requires me to pull about 45 feet of line though the block arrangement.  The hoist line is ancient so I have decided to replace it with Amsteel.  Rightly or wrongly, I am thinking of using 3/8 inch Amsteel (not for strength but because IMHO it will fit better in the existing triple block).
Doing as stated above, I will need an electric winch/hoist that will be able to pull-in/pay-out about 45 feet of 3/8 (12/32) inch Amsteel.  I do not need much winch/hoist pulling strength (that is a winch/hoist capable of 1000-2000 pounds of pull is way overkill but is about as small as they make them).  BUT these size winches/hoists only hold about 50 feet of 5/32 inch steel cable (I was going to throw out the steel cable and thread in the Amsteel).
Now my dilemma ..... 
In reading about winches/hoists, they state to leave at least 5 (or more) turns of wire on the drum when using them to pull-in (and I assume pay-out).  So if I need to pull-in/pay-out 45 feet of 12/32 inch Amsteel, I would need to have a winch/hoist capable of holding about 55 feet ???? (question marks on purpose)  of 3/8 inch Amsteel. 
I think I have a couple choices....
1) I can buy a hugely powerful and big winch/hoist ... something like this Warn (and yes I see this is a winch and not a hoist with a true brake).... it has a 12000 pound rating and holds 80 feet of 3/8 inch wire rope
   https://www.warn.com/truck/winches/VR12000_winch.shtml
2) I can use only 2 (or maybe 1 of the pulleys in the triple block) to lessen the amount of line it will take to raise the boom to near vertical; but this of course will increase the "pull" required to lift the 250 pound dingy/motor.  I could then get a smaller winch/hoist but I still wonder if required amount of 3/8 inch Amsteel will fit in the smaller winch and if the smaller winch will handle the load without overheating and shutting down.. That is I have also read about winch/hoist duty cycles.. some winches/hoists have a 5% duty cycle at full load... like I have read some winches/hoists state use them 45 seconds (at full load) and then have them off for 15 minutes ...  Finally winch/hoist speed is a concern... some spec out at 5 -7 feet per minute and others spec out at 25 feet per minute....  I cannot image using a winch/hoist at 5 feet per minute in my situation...
Jeez.... what do I do now?  Any advice? 
Specifically those of you using Amsteel (or any 3/8 inch fiber), what winch/hoist are you using?  How much line to pull-in/pay-out?  How much line (if any) do you leave on the drum?  
Jim Gano
_______________________________________________
http://lists.trawlering.com/mailman/listinfo/trawlers_lists.trawlering.com

To unsubscribe or modify your subscription options (get password, change email address, etc) go to: http://lists.trawlering.com/mailman/listinfo/trawlers_lists.trawlering.com
Trawlers & Trawlering and T&T are trademarks of Water World
Productions. Unauthorized use is prohibited.

[Mark Richter via Trawlers-and-Trawlering]

Jim,
I've added an electric hoist to one K42, and will be doing another in June.

I think you are making this hoisting a lot more difficult than it needs to be. Forget 3/8" line, it takes up too much room on the drum and is far stronger than needed. Get a real hoist of 1000 lb actual capacity, like a Warn DC 1000; the safety factor is already built-in. It can use 7/32 wire or advanced fiber rope, and can hold around 55 ft on the standard drum. Run the line from the hoist over a single sheave at the mast head, through a single block at the boom end, and fasten to an eye at the masthead for a 2:1 advantage. I'd do this mainly to slow the speed of lift of the boom, as you aren't lifting the boom as far as you would be lifting the dinghy from the water. As the boom lifts and gets close to vertical, you want fine control.

Check carefully the clearance of your boom gooseneck as the boom approaches vertical. Stress on this part gets large at high angles, and many are not designed for such high angles.

Warn also makes a DC 800 lb hoist with a shorter drum. You can probably use this one with the 2:1 advantage for the boom, and a 1000 lb for the dinghy with its larger drum capacity. Warn also makes this series of hoist in 1200 lb and 1600 lb sizes for big dinghies. All 4 come in 12v or 24v models.

If using a second hoist for lifting the dinghy, no mechanical advantage should be needed. Just run from the hoist drum to a block at boom end, and down to the dinghy attach point. Which brings up the next subject, lifting slings/spreader bars.

Mark Richter
Mark's mobile Marine
Ortona, FL on the Okeechobee Waterway

Sent from my iPhone

[Wayne Beardsley via Trawlers-and-Trawlering]

Jim,

I am of the opinion that 3/8ths Amsteel is way overkill for your boom lift
application. The breaking strength of this stuff is comparable to
stainless wire of the same diameter and your maximum loading is under 100
lbs with a 3 to 1 purchase. I'd be inclined to go with either 3/16ths or
1/4 inch which should give you plenty of turns on the drum. The biggest
issue I've found with Amsteel is that it is very slippery stuff which
requires extra care with knots.

By the way, Tractor Supply stores have some good 12 volt winches at
reasonable prices.

Regards,

Wayne Beardsley
GB49 Classic, Long Legged Lady

[Jim Gano via Trawlers-and-Trawlering]

Thanks all for the advice.... As I stated 3/8 inch Amsteel is way overkill for me... I think I will get smaller diameter Amsteel and use less passes on the triple block...
Mark Stated: 

"Which brings up the next subject, lifting slings/spreader bars. "

I had inherited from the PO a 4 foot long 2 x 4  "lifting slings/spreader bars" with chain/clips going down to 3 points to attach to my dingy (two stern; one bow) and two chains coming up to attach to the common lift point .  I am abandoning  that in favor of 3 nylon lines/with clips connecting up to a single lift point.  The old 2 x 4 worked fine but when used was (1) heavy and cumbersome (2) tended to bang my teak rail (3) difficult to store (4) a little dangerous as it swung around.... etc ect.  

[Robert Phillips via Trawlers-and-Trawlering]

< Forget 3/8" line, it takes up too much room on the drum and is far stronger than needed. >

I have used Spectra/Dyneema, called Amsteel by Samson, for ski-boat hoists on my sister's lake in Colorado and discovered uncovered Spectra/Dyneema to not have the chafe resistance needed for cheap pulleys and electric hoist drums. We went to New England Ropes' T900, which is a blended core of Dyneema and Technora with a polyester cover. The 1/4" is good for 4400 lb.

If needing a smaller line NER's Endura Braid, Dyneema core/polyester cover. 3/16" good for 2250 lb.

Another good value line is NER's Salsa Line, which is a combination Dyneema and polyester. The 6mm is good for 2850 lb. I use this for tying our hurricane protection screens as it doesn't slip when knotted like solid Spectra/Dyneema will under load; when tying Spectra/Dyneema you must put an overhand knot in the tail of the primary knot as close as you can get it to the primary knot.


Robert Phillips
Doyle Sailmakers BVI, Ltd.
b...@doylecaribbean.com
Mobile 284-541-2206
Office 284-494-2569

[TW Collins via Trawlers-and-Trawlering]

Jim,

On the subject of spreader bars (sometimes called strongbacks) for
lifting dinghies, their primary use is to minimize the clearance needed
between the dinghy and the hoist. Using cables or straps, as you
describe, from the dinghy lifting eyes brought to a single point creates
additional forces in the straps and in the lifting eyes, and also
produces a collapsing force on the dinghy itself. The greater the
angle of the lifting straps off of vertical, the less the clearance.
However, this angle also increases the total tension in the straps and
on the lifting eyes and the dinghy. The amount of increased force is a
cosine function of the angle of the lifting straps off of vertical.
Roughly, for a 45 degree angle, the force will be 1.5 times the vertical
force. For 60 degrees it is 2 times and for 70 degrees it is about
three times the force. Using a spreader bar overcomes this disadvantage.

Tom Collins - Misty Sea

[Eric Thoman via Trawlers-and-Trawlering]

>On the subject of spreader bars (sometimes called strongbacks) for lifting
dinghies, their primary use is to minimize the clearance needed between the
dinghy and the hoist. Using cables or straps, >as you describe, from the
dinghy lifting eyes brought to a single point creates additional forces in
the straps and in the lifting eyes, and also
>produces a collapsing force on the dinghy itself.

Reply:

Long straps, short straps, or no straps? I can tell you our experience. We
have a 7000 pound knuckle crane on board that we use to pick boats and
routinely pick a dock full of kayaks that we use in our charter business.
Our runabout is about 2000 pounds loaded with fuel and the dock full of
kayaks is about 1000 pounds. During the summer we load and offload the kayak
dock daily. After 15 years we still occasionally find a new trick or
technique. Most importantly, it takes good communication between the deck
person and the crane operator in order to be safe and efficient. And yes,
the deck person wears a hard hat. In any event, if you are using your crane
a lot, at some point you will experience a rolling boat and a suspended
dinghy. The challenge is to minimize the swing of that load. We found that
longer straps (12 feet) are easier for the deck person to hold the load
steady while the boat rolls. It is surprising how little effort it takes by
putting a steady force (leaning back) on two lines connected to the load.
We found that a spreader bar makes for a snappier load that is less
predictable and harder to control. The Bering Sea crab guys use no straps
at all. They hook the trap and suck it all the way up to the end of the
knuckle crane. A little cage at the end of the crane holds the trap in
contact with the crane. Given the extreme conditions they are in, straps and
a swinging load would be dangerous. The downside is the crane takes the full
force of the movement of the load as the boat rolls. Occasionally a crane
will break its turning gear and become loose as a result. The thought of a
runaway crane has always terrified me and we do our best to avoid anywhere
near that much sideways pressure on our crane. The long straps help.

Eric Thoman
Abyssinia

[Rich Gano via Trawlers-and-Trawlering]

Eric's discourse on the use of long straps (or bridle legs, if you will) and
steadying lines reminds me of my days as the first lieutenant in an
amphibious attack ship where we routinely used our boat and aircraft crane
to lift out our four landing craft and control boats. We used four-legged
wire rope bridles with a fairly small angle between the vertical and the
legs. Because we had to traverse the crane some 200-plus degrees to get
each of the 36-foot boats to the deck's edge where the crew was loaded
before lowering the boats to the water, we used a crew of eight men and a
boatswain's mate to handle the four 2-inch nylon steadying lines secured to
the four "corners" of the boats. Even a 2-degree roll of the ship could send
those boats wildly out of control unless each line was perfectly eased or
taken in as the crane traversed because they were at the end of probably a
50-foot pendulum.

Back then we also had another class of amphibious warfare ship which carried
all sorts of larger landing craft including the 60-ton LCM-8s. These ships
were fitted with large booms which were skillfully used in pairs to sway out
these big craft. The wire rope bridles used to move these vessels had legs
about as thick as a weightlifter's wrist.

My ship could also haul these big LCM-8s, but we had a floodable well deck
into which the craft motored, but the boats had to be carefully controlled
with eight 3-inch nylon steadying lines tossed down to the boat's crew as
they entered the well. The reason for the control was quite evident when
the ship would rise and fall on a swell creating 6-8 foot surf in the well.
An out of control LCM could end up beached on the steel ramp at the forward
end of the well with no way for us to lift it off or crashing into the boat
ahead since we held four boats in two rows of two.

Maybe the answer to all this is what our SEALs are employing in certain
vessels, a ramp you just drive the dink onto at full speed as the mother
ship is underway at speed! I am sure we will see more of this variation in
the civilian market.

Rich Gano
Calypso (GB-CL42 Hull 295)
Panama City, FL