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Catalina/Capri 25/250 Sailor's Forums

General Sailing Forum

Boom Weight Limit

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justinkonecny
1st Mate

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USA
33 Posts

Initially Posted - 07/02/2015 : 15:24:39

Last crab season I scratched and dinged my hull pulling pots. I was thinking about putting a block and swinging the boom over to pull the pots up out of the water and then carry them back into the cockpit. Anyone got an idea on the weight limits for the boom?

Blog of my first boat: http://justinkonecny.wordpress.com

TakeFive
Master Marine Consultant

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2269 Posts

Response Posted - 07/02/2015 : 20:54:05

The main issue may be the size/strength of your topping lift, since that will bear more tension than your boom's compression. Do the force vectors and you'll see that there's a compressive force on the boom that is probably a lot less than the downward force from the weight of the pots. And chances are it's less than the compressive force created by a well-tensioned outhaul (which probably has at least 2:1 purchase). Do the calculations and you can probably figure it out for yourself.

Rick S., Swarthmore, PA
PO of Take Five, 1998 Catalina 250WK #348 (relocated to Baltimore's Inner Harbor)
New owner of 2001 Catalina 34MkII #1535 Breakin' Away (at Rock Hall Landing Marina)

Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts

Response Posted - 07/02/2015 : 21:05:25

How do you plan to keep the boom out away from the hull?

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

Kim Luckner
1st Mate

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USA
96 Posts

Response Posted - 07/03/2015 : 08:05:34

I can't imagine a crab pot could way any more than 25 to 30 lbs? It's just wire mesh with some critters inside.

Seeadler
'79 C25 SR/FK #1432
Mentor Lagoons

Voyager
Master Marine Consultant

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USA
5231 Posts

Response Posted - 07/03/2015 : 21:05:27

Frankly when I'm in the cockpit just standing around I put more weight on the boom's topping lift just by pulling myself up than a 30# weight applied out at the end of the boom. By force of habit whenever I walk up the companionway steps I grab the boom for support. The lever arm makes a difference of course - putting 30# in the middle of the boom creates only 1/2 the force a 30# weight creates when applied at the boom end.

Bruce Ross
Passage ~ SR-FK ~ C25 #5032

Port Captain � Milford, CT

Dave5041
Former Mainsheet Editor

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USA
3754 Posts

Response Posted - 07/04/2015 : 19:37:26

I hoist myself with the mainsheet into a kayak and am probably heavier than a crab pot. Tie the boom off to the cleat aft of the winch with a vertical line, not from the end of the boom. A clove hitch around the boom to a cleat hitch works well. As noted, the key is the topping lift.

Dave B. aboard Pearl
1982 TR/SK/Trad. #3399
Lake Erie/Florida Panhandle

TakeFive
Master Marine Consultant

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2269 Posts

Response Posted - 07/04/2015 : 19:53:55

quote:
Originally posted by Voyager

Frankly when I'm in the cockpit just standing around I put more weight on the boom's topping lift just by pulling myself up than a 30# weight applied out at the end of the boom. By force of habit whenever I walk up the companionway steps I grab the boom for support. The lever arm makes a difference of course - putting 30# in the middle of the boom creates only 1/2 the force a 30# weight creates when applied at the boom end.

Not to pick nits, but if the issue is how much force it would take to buckle the boom, applying weight at the midpoint of the boom may be more stressful than applying it at the end of the boom. In the latter case, the vast majority of the weight is borne by tension of the topping lift. In the former case, applying weight at the middle of the boom results in half the weight being borne by the topping lift (the other half by the gooseneck). But you still have the full downward force at the center of the boom, which could buckle the boom if there was sufficient weight. In fact, I would bet that it takes far less weight to buckle the boom if applied at the center than if applied at the end.

As for OP's original question, I think the weights we are talking about are far more than a crab pot is likely to have. But who knows, those Dungeness crabs are pretty big and heavy!

Rick S., Swarthmore, PA
PO of Take Five, 1998 Catalina 250WK #348 (relocated to Baltimore's Inner Harbor)
New owner of 2001 Catalina 34MkII #1535 Breakin' Away (at Rock Hall Landing Marina)

Stinkpotter
Master Marine Consultant

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Djibouti
9013 Posts

Response Posted - 07/04/2015 : 20:17:35

If the lift point is at the end of the boom, then indeed it's all on the topping lift and therefore the mast--all of which should be able to handle a lot more than a crab pot. It's also where people have rigged tackle to lift outboards and even crew-overboard. If at mid-boom, then the boom itself is a factor, but at least several people have rigged mid-boom sheeting on C-25s, which almost certainly puts more stress on the boom in heavy air than a crab pot ever will. But remember the disclaimers on this forum... The legal value of this advice is no more than you paid for it!

Dave Bristle
Association "Port Captain" for Mystic/Stonington CT
PO of 1985 C-25 SR/FK #5032 Passage, USCG "sixpack" (expired),
Now on Eastern 27 $+!nkp*+ Sarge

DavidBuoy
Admiral

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USA
707 Posts

Response Posted - 07/05/2015 : 04:42:02

Captain Rob & Admiral Alyson
"David Buoy"-1985 C25 SK/SR #5053

DavidBuoy
Admiral

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USA
707 Posts

Response Posted - 07/05/2015 : 12:09:05

Captain Rob & Admiral Alyson
"David Buoy"-1985 C25 SK/SR #5053

justinkonecny
1st Mate

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USA
33 Posts

Response Posted - 07/07/2015 : 10:19:11

Thanks for the help! It totally works and makes pulling the pots way easier. Without using the assistance of the winch, pulling six pots twice a day gets really tiresome.

Blog of my first boat: http://justinkonecny.wordpress.com

Lee Panza
Captain

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USA
465 Posts

Response Posted - 07/18/2015 : 20:18:10

Wow, David, where'd you trap that mermaid? And just a can of soda pop for bait?

I wanna go THERE next summer! Sure beats our West Coast Dungeness. ;)

The trouble with a destination - any destination, really - is that it interrupts The Journey.

Lee Panza
SR/SK #2134
San Francisco Bay
(Brisbane, CA)

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The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.