T-top Crab puller question

Wow, what a bending moment that will impart to that hardtop leg.

Please post photos after it bends and ruins your hard top. :hmm

Brian

Sea Shift said:

You really think it will bend the hard top supports? There are two welded 2" tubes. I can hang on it and it doesn't even flex and thats 250 lbs. Hmm

Click to expand...

Hanging on it applies a compression load to the vertical support struts. They are very strong that way.

The arrangement you propose has a 45* support member and it will transfer a vertical load to the tube it is attached to, and a "bending moment". That bending moment is a load at the top of the tube pulling it outward in the direction of your puller, and an opposite force lower on the tube, where the 45* member attaches, in the opposite direction.

I can't tell you that the tube will bend, but I can say you be applying loads to it that it was not designed for. I certainly wouldn't do it on our boat.

http://www.lainefamily.com/CrabpotPullerProject.htm

http://www.go2marine.com/product/243199F/gunnel-mount-bracket-only.html

http://www.go2marine.com/product/243198F/kickplate-bracket-only.html

Good luck with your project.

Brian

I was thinking about this one myself, I like projects, but time we have left over to do projects is never enough!

To the link of the home made setup. Take the square tube SS and take it along the entire hardtop top straight across in line with frame bolted down into the frame in 3 places, and extend out like a boom to proper lenght over side, and add one vertical leg slightly tilted toward the hardtop with the foot on top of the gunnel and weld to the horiz tube, just weld to a flat plate at bottom, bolt down to gunnel top. Then like the link project add the plate at the boom end and hole for pulley,winch, etc The weight on the boom will tend to lift the hardtop which it is not likely, and lateral force shouldn't be that much but if so add a 2nd vertical leg going to an angle forward and land on same gunnel. As i think about it, the (not exactly) A shape vertical frame will be it, connected to the horiz tube, perhaps entirely removable A frame. I don't like alum for this but if so must be very heavy gauge. SS is right choice for me. Square tube works, the larger the tube dimensions the better.

I would make the tube extending past the vertical leg like a tube in a tube with some kind of pin to take apart so it doesn't stick out when not in use.

I'm done. Speedymetals.com etc for supplies, has specs too. And welder.

Me I'd like to convert my Sailfish OEM hardtop plus plastic window/canvas setup into a 3 sided pilot house designed with real glass to see out, open back with extender canvas on rear sides and across stern (like the Judge 27 setup). This vs. $3K or more for new canvas due soon, as well. I'm sure the boat may tend to roll more, glass is heavy, there will be more glass than now. How much more not sure. Need time on drawing board first, or find someone who did it. tired of looking out of plastic, never could ever be the same as glass. I have the glass marine window maker already with stock sizes.

The crab puller is easier. I'd use it for lobster traps here. With block and tackle, no motor.

John Carroll
Winterville Machine Works
252-756-2130

Call this person. He is the one that made your top.

I'm not sure I'd want to have that hanging off the pipes, they are fairly thin walled. An even 50 pounds of pressure probably wouldn't cause harm but all you would need is a wake to hit at the right time and give you a good roll. The line would go slack and then shock the system which might kink a pipe.

Why not put a davit through the gunnel into the deck?

I'm new to Grady Whites, but I would definatly mount it to the hard top poles, in fact Im going to liberate your idea and weld up some folding arms to do just about the exact thing you mentioned, I may be new to Grady's but not new to boating and I am an aluminum welder with many many years of fabrication experience behind me . Unless your pulling up comercial traps with the 1"thick steel rod across the trap for weight and 2 of them at a time, you should not have any issues with your design. :mrgreen:

http://www.acelinehauler.com/#nogo

Hello Guys, I guess you can't access these south of the border or can you? I have used one of these for about 6 years now for pulling prawn traps. Two traps on a string from 300 to 400 feet. Says it will hoist up to a hundred pounds, haven't been that lucky yet on a prawn haul. Anyway it fits on a scotty down rigger mount. I reinforced the underside of the gunnels with aluminium plate. Have had no issues with movement in the gunnels on my 208 (yea grady for well built). Have had days up here off Vancouver Island where 400 prawns (the daily limit for 2 licences) have been an easy haul. Thought I would give my 2 bits to this topic. Cheers trapper.