Boom extension for lifting.......

jviss · Mar 1, 2022

I like these kind of problems, but I must say, with a new genset, and the risk of damage to your boat, and injury to yourself, I strongly encourage you to go to a boatyard that has a crane and can just drop it in for you.

My yard uses a crane to launch boats and set masts. They have lifted the engine out of my C36 and dropped it back in, with ease. It would have been a dangerous nightmare for me to do it myself.

sailme88 · Mar 1, 2022

If your boat is on the hard, go to an equipment rental center , Lowes or Home Depot and rent a bucket lift. 1000lb capacity. Attach your block and tackle beneath the bucket. 4 hr rentals around $150.00 depending on the market...

smokey73 · Mar 1, 2022

What could possibly go wrong? It might be a good way to test the impact strength of fiberglass or prove you earned your Boy Scout lashing merit badge. If you do it yourself with the lashed on boom extension, be sure to take good videos so you can submit them for the Annual Darwin Awards if something does go wrong. :beer:

Just kidding, but is the risk really worth the reward?

JamesG161 · Mar 1, 2022

NYSail said:
The units weight is 200lbs

Are you sure it is not 200 kilos?

Most engines for a genset weigh 200 lbs.

Jim...

jssailem · Mar 1, 2022

While the boom looks convenient, lashings can be mostly secure, and with leverage working against you putting the boom/boat/ and you if you are beneath the system - DON'T DO IT MAN... YOU HAVE YOUR WHOLE LIEF AHEAD OF YOU.

If this is a test you feel compelled to attempt, then get the genset on the boat, and rig a Tripod out of 2x4's or better 4x4's positioned over the hole. Use your block and tackle skills to raise the genset up and lower it beneath the rigging. You can then raise and lower the genset with out being under it.

smokey73 · Mar 1, 2022

I have installed a Nextgen 5.5KW myself but was able to use a manual chainfall crane that our club used to launch and retrieve small sailboats. I could position the boat directly below the drop point and slowly and very carefully lower it into port lazarette with only about 1/2 inch clearance. Worked great. I considered the boom idea but wasn't comfortable with the potential "point loading" on the attachment point on the boom

Since you are on the water and can pull up to a dock could you use an auto engine lift on the dock. Not sure if it will have the reach from the dock but its worth looking at.

I've lifted a 4 cylinder engine from a Lotus car with a strong iron pipe, nylon strapping and two strong young men. I"d be more comfortable with that than some jury-rigged lashed extension to your boom. Even with the boom extension (I assume to get it from the dock to the boat) you'll still then have to repositon it on the boat to get it down the hatch. Why not the strong young men, iron pipe and a little brute force method to get it on the boat and then the boom or some other rig to get it down the hatch?

JamesG161 · Mar 1, 2022

NYSail said:
200 lbs. Nextgen 3.5kw

Nice find.
I am replacing my 9KW Kolher and that shows theirs at 330lb or the same weight as my new Kolher with Sound Enclosure.
_____
To answer your question, I am an Engineer, boom lift use = NO.

Why?
The connection to the Mast is undersized for that weight.
Jim...

PS: I will have to separate the Engine from the Generator Head to get inside my boat. Two strong dudes will help me.

dLj · Mar 1, 2022

NYSail said:
OK so this is a question for the engineers......

I am purchasing / installing a new genset. The units weight is 200lbs and I am dropping it into the boat myself. Getting it there is no issue, however, it has to go down the cockpit lazerette and I was hoping to use my boom to attach a block and tackle to help ease it in. However the boom is about 3 feet too short. Question: If I lash / connect an extension onto the boom, then place the topping lift on the end of the extension where the block would be attached, would this give adequate strength? Seems like it should be no issue to me, but then again I am not an engineer. btw topping lift is new and plenty strong

Thanks
Greg

200 pounds is not to bad. I don't see a concern with loading but I'd really have to look at your boats set-up. You'll need enough height to hang eh genset, plus your block and tackle or however you'll raise and lower the genset. Takes a lot more space than one may think.

I'd be looking at taking two beams running down each side of your boom, lashing them in two places on the boom. You might need to make spacers/wedges to add stability. Then I'd cut spacers to fit into the free end. One spacer I'd put right at the end of the boom, one mid way, and then another where you'll hang the genset and connect the topping lift. These spacers I would lag bolt to the beams running along the boom. Pretty easy to build.

If you would like help, I'm not overly far from you...

dj

dj

jssailem · Mar 1, 2022

NYSail said:
I hear of people lifting engines all the time with their boom so just assumed it would be fine to do.

They do. There are not many posting, Man I hooked up the engine to the Boom. It broke in two , now I am looking for a new boom and repairing the damage to my boat... Watch it on YouTube.

The successful ones get bragged about. It is a common trait for humans.

Greg. There is a chance that you could do it successfully. There is also a chance you could win the TriFecta at Belmont. What you need to determine is what are the odds and are they in your favor.

JoeWhite · Mar 1, 2022

I lifted my 4D 90lb batteries this way and lowered them down into the cockpit. There was just enough room to lift them with unmodified boom from the dock into the cockpit. The blocks themselves require certain amount of length, so the batteries just cleared the combing, the boat tips when you lift it then when the boom is centered the boat straitens up causing an unexpected swing.
I would not want to try this with an extension and 200lb at the end.

markwbird · Mar 1, 2022

If you do it right then, yes. Realize that the attachment to the boom must be very strong as I assume the boom will not be supported by an additional topping lift. If I were going to do it I would use my spinnaker pole as the extender so I could lash it to the boom at the end of the boom and also at the forward end of the spin pole. Then I would have to decide how to support the boom. It may be better to support the boom with the topping lift at the end of the boom rather than at the end of the extension and just let the extension cantilever out. The other option would be to support it at the end of the extension AND at the end of the boom using a halyard. You would still need a very string connection between the extension and the boom.
My spin pole is 3.5" dia. aluminum pole so it can probably carry the 200 lbs at 3ft out but I would run the numbers on that first. The next issue is how much is the boat gonna heel when you try to lift it off of the dock? You may need to get some rail meat to stand on the other side.

jviss · Mar 1, 2022

jssailem said:
Watch it on YouTube.

link?

Tally Ho · Mar 1, 2022

markwbird said:
If you do it right then, yes. Realize that the attachment to the boom must be very strong as I assume the boom will not be supported by an additional topping lift.

I was going to suggest this…whatever you use to extend, have a topping lift support the aft end of the boom as well as the extension, and another halyard supporting the rear end of the extension…

The boom would essentially just keep the extension held out away from the mast, and the 2 lines are supporting the extension on each end…crude drawing below…

Greg

Davidasailor26 · Mar 1, 2022

Tally Ho said:
I was going to suggest this…whatever you use to extend, have a topping lift support the aft end of the boom as well as the extension, and another halyard supporting the rear end of the extension…

The boom would essentially just keep the extension held out away from the mast, and the 2 lines are supporting the extension on each end…crude drawing below…

View attachment 203086
Greg

I thought about that too. It will make the bending force on the extension much less. But it will also put the extension into compression against the boom. It will be very hard to lash the extension in such a way that it doesn’t slide forward along the boom in that arrangement.

Tally Ho · Mar 1, 2022

Davidasailor26 said:
I thought about that too. It will make the bending force on the extension much less. But it will also put the extension into compression against the boom. It will be very hard to lash the extension in such a way that it doesn’t slide forward along the boom in that arrangement.

Yes.agreed. Have to be creative to find a way to keep the extension from moving into the mast.

Greg

Boom extension for lifting.......

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SBO Weather and Forecasting Forum Jim & John

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SBO Weather and Forecasting Forum Jim & John

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SBO Weather and Forecasting Forum Jim & John

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SBO Weather and Forecasting Forum Jim & John

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