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Old 08-11-2022, 16:34   #1
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Need to lift my stern out of the water a little. Pillows?

I am in an area with very limited changes in water depth. And I am at a dock.

We had a problem with the outboard mounts that were created out of fiberglass.

We tried our best to replicate the old wooden ones that I had made as temporaries, but something is off by about a half an inch.

We were thinking of pulling these mounts out of their spot, and trimming them down. They are bolted together and the problem is if we cut the half inch off, that creates a place we cannot bolt to anymore without going a full inch in.

If we go out for an inch, the Outboard will still not make it through the hole in the bottom of the well. It’s currently not making it through the hole either. But it’s dragging on the stern part. If we go 1 inch shorter it will drag on the forward part of the hole at the bottom of the well. If we go to the proper 1/2 inch, we will have nowhere to bolt to because there are already existing bolt holes in the side panels of this bracket .

I hope that made sense. Hard to explain in words.

In any case, due to the above, unless somebody has some really creative ideas, I need to lift the stern of the boat up about 10 inches or so. Maybe less, but 10 inches is a good conservative number for this.

I need to lift the boat up so I can make the outboard well cutout 1/2 an inch bigger at the aft part of it.

Has anyone used those flotation pillows before? Are there other types of things that can be used for a flotation pillow? My entire boat displaces 18,000 pounds.

Oh it’s got a ton of junk in it right now. Just lots of construction stuff. All sorts of extra weight. It’s probably currently displacing around 16,000 pounds.

I only need to lift one corner at a time, so I think I might need about 4000 pounds of lift? Not even. Because I don’t have to lift it all the way either. Just about 10 inches up in one aft corner and then 10 inches up in the other aft corner.

Just need to get the outboard well free of the water for a little bit to grind out half an inch off the back of it, de core, then fill that with epoxy to seal off. Then drop it back in the water.

Then do the other side.

All pretty straightforward except getting some sort of pillow flotation thing to lift each stern up a bit.

Has anyone done this before?

Currently thinking how nice it would be to have a spud barge. Ha ha
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Old 08-11-2022, 17:01   #2
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Re: Need to lift my stern out of the water a little. Pillows?

Move half your junk to the bow?
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Old 08-11-2022, 17:03   #3
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Re: Need to lift my stern out of the water a little. Pillows?

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Originally Posted by Deep Blue Water View Post
Move half your junk to the bow?
Have definitely been considering that. But we need to do things more quickly than that.

Also it’s not guaranteed to work.
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Old 08-11-2022, 17:05   #4
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Re: Need to lift my stern out of the water a little. Pillows?

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Originally Posted by Deep Blue Water View Post
Move half your junk to the bow?


Probably safest. A pillow under the stern slipping out or deflating after you cut the hole and glug, glug.
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Old 08-11-2022, 17:09   #5
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Re: Need to lift my stern out of the water a little. Pillows?

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Probably safest. A pillow under the stern slipping out or deflating after you cut the hole and glug, glug.
No glug glug.

I need to make a hole in the bottom of the boat a little bigger than it is now. By 1/2”. And only on the aft part of the hole.

The hole is wide open to the sea now. It’s the hole at the bottom of an outboard well. The hole currently sits 10” or so below the water in the outboard well.

For some reason, it wa very hard to describe it well in the first post. Sorry about that
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Old 08-11-2022, 17:19   #6
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Re: Need to lift my stern out of the water a little. Pillows?

Can you heel the boat far enough to one side to the corner you want to work on? Then repeat to other side?



Halyard from top of mast works pretty well if you have something to tie to. Or use your boom or spin pole as a jib arm, supported by topping lift or halyard, with load off the end. Water makes great ballast.
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Old 08-11-2022, 17:21   #7
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Re: Need to lift my stern out of the water a little. Pillows?

You can rent them apparently. I'd just hook one on each side of the hull with straps under and then inflate.

https://rentaltoolsonline.com/joint-...AaAmlsEALw_wcB
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Old 08-11-2022, 17:48   #8
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Re: Need to lift my stern out of the water a little. Pillows?

You come up with some unusual requests....that's for sure.

Were it me, I'd look for someway to hoist the stern up. Maybe use a neighbor's mast or something like that.
If that is not available, I'd try to make a temporary hoisting platform out of 2x4's, etc. Mount it on the dock by the stern. Use a come along winch to crank up whatever you've devised as a strap around the stern you want to raise.
If you can park a vehicle nearby, you could also use this for pulling power.
There must be several ways to set up a block and tackle rig.
Fenders have a tremendous amount of buoyancy. If you can arrange to pull one or more under your stern.
You can rent these dollies that you use to lift an engine out of a car. It has two splayed legs on rollers and arm. Might be the perfect thing. Attach a come along to the arm, and winch the stern up. Any rental place will carry these.

Ok, all I got for now...
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Old 08-11-2022, 18:23   #9
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Re: Need to lift my stern out of the water a little. Pillows?

Really like to see some photos to get a better idea of what can be done.
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Old 08-11-2022, 19:23   #10
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Re: Need to lift my stern out of the water a little. Pillows?

For those who can’t picture it, Chotu has a 50’ catamaran. No inboard engines, two outboards that sit in wells at the eft end of each hull. Think almost like a saildrive, but an outboard sitting in a well. He needs to lift the aft end of each hull to make adjustments to the wells.

Chotu, on our trimaran we used to carry a couple of truck tire inner tubes to do exactly this. For more lift, one or more industrial dunnage bags would do the same thing. If you can stand their politics ULine Industrial-Dunnage-Bags (there are other vendors). With either a tube or a bag you jump in the water with it deflated, stretch it under the hull nearly centered, connect an air compressor, inflate about 3/4 full. That last is important, you want to inflate as much as you can to get the lift, but leave enough sag that it stays folded under the hull so it doesn’t have a chance to slide out. Can use ropes/straps to assist with holding in place. Since your hull has the outboards and transom hung rudders you should be able to put the bags near the aft end, just lifting the corner on which you want to work. The bags are less than $10 a piece, should fit the budget, although shipping may cost more.

Alternative B, if the materials you need to cut are impervious to water (i.e. a solid glass laminate or similar), you could rent a pneumatic or hydraulic saw that can be run in the water. Used to use a hydraulic chainsaw for cutting off wood piles at the mud line, and I know there are other saws with more finesse that you can get for underwater use. You could even use a pneumatic grinder with a coarse disc if the area you need to shape is small.

Here’s a photo of a cat with a much larger bag under the bridge deck:
Click image for larger version

Name:	26BD0972-3AEF-4F00-9F7A-6B5F10FB3D63.jpeg
Views:	162
Size:	84.3 KB
ID:	266991
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Old 08-11-2022, 19:52   #11
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Re: Need to lift my stern out of the water a little. Pillows?

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Originally Posted by HeywoodJ View Post
For those who can’t picture it, Chotu has a 50’ catamaran.
It's the wells and surrounding structure that I'd like to see.
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Old 08-11-2022, 20:05   #12
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Re: Need to lift my stern out of the water a little. Pillows?

My friend Larry Christensen raised the stern of his trimaran Invictus about a foot by placing empty plastic barrels on the bows and filling them with water.

He then built a sugar scoop on the center hull. Finished it the night before he had to depart on a delivery to Swiftsure.

Larry was a character, he extended HIS mast by 11 feet by welding a section of a light pole to the top (a section which he flattened by placing it inside a big I-beam and using several hydraulic jacks, which turned funny when the I-beam opened up and the jacks all shot skyward and then rained down, fortunately missing Larry. Try two worked.) Then he bought some used sails from a Santa Cruz 70. Pretty big sails for a 50 foot wooden tri.

Larry said his wife thought "Damedboat" was one word.

Larry raced Invictus in the Jack and Jill series, without his wife. He wanted to go single-handed but the rules called for a man and a woman. So he picked up a bar fly the night before and thus qualified.

Larry was unstoppable.

Maybe like you, Chotu.
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Old 08-11-2022, 22:03   #13
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Re: Need to lift my stern out of the water a little. Pillows?

Quote:
Originally Posted by HeywoodJ View Post
For those who can’t picture it, Chotu has a 50’ catamaran. No inboard engines, two outboards that sit in wells at the eft end of each hull. Think almost like a saildrive, but an outboard sitting in a well. He needs to lift the aft end of each hull to make adjustments to the wells.

Chotu, on our trimaran we used to carry a couple of truck tire inner tubes to do exactly this. For more lift, one or more industrial dunnage bags would do the same thing. If you can stand their politics ULine Industrial-Dunnage-Bags (there are other vendors). With either a tube or a bag you jump in the water with it deflated, stretch it under the hull nearly centered, connect an air compressor, inflate about 3/4 full. That last is important, you want to inflate as much as you can to get the lift, but leave enough sag that it stays folded under the hull so it doesn’t have a chance to slide out. Can use ropes/straps to assist with holding in place. Since your hull has the outboards and transom hung rudders you should be able to put the bags near the aft end, just lifting the corner on which you want to work. The bags are less than $10 a piece, should fit the budget, although shipping may cost more.

Alternative B, if the materials you need to cut are impervious to water (i.e. a solid glass laminate or similar), you could rent a pneumatic or hydraulic saw that can be run in the water. Used to use a hydraulic chainsaw for cutting off wood piles at the mud line, and I know there are other saws with more finesse that you can get for underwater use. You could even use a pneumatic grinder with a coarse disc if the area you need to shape is small.

Here’s a photo of a cat with a much larger bag under the bridge deck:
Attachment 266991

Wow!!!!

You really understand this issue and have some fantastic suggestions!

Thanks for this post and for sharing what flotation products to use to get the job done.

I’ll do precisely this.

Your post could be a sticky on the subject. Thanks!!
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Old 08-11-2022, 22:05   #14
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Re: Need to lift my stern out of the water a little. Pillows?

Quote:
Originally Posted by wingssail View Post
My friend Larry Christensen raised the stern of his trimaran Invictus about a foot by placing empty plastic barrels on the bows and filling them with water.

He then built a sugar scoop on the center hull. Finished it the night before he had to depart on a delivery to Swiftsure.

Larry was a character, he extended HIS mast by 11 feet by welding a section of a light pole to the top (a section which he flattened by placing it inside a big I-beam and using several hydraulic jacks, which turned funny when the I-beam opened up and the jacks all shot skyward and then rained down, fortunately missing Larry. Try two worked.) Then he bought some used sails from a Santa Cruz 70. Pretty big sails for a 50 foot wooden tri.

Larry said his wife thought "Damedboat" was one word.

Larry raced Invictus in the Jack and Jill series, without his wife. He wanted to go single-handed but the rules called for a man and a woman. So he picked up a bar fly the night before and thus qualified.

Larry was unstoppable.

Maybe like you, Chotu.
This was also a really good post. Definitely had me laughing. That guy sounds like a nut. In a good way.

Thanks for sharing. I think that could work also. Putting a ton of weight on the bows and just using the rocker of the boat itself to get those sterns up higher.
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Old 08-11-2022, 22:11   #15
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Re: Need to lift my stern out of the water a little. Pillows?

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Originally Posted by boatpoker View Post
It's the wells and surrounding structure that I'd like to see.
It’s a lot of black on black here. But I had this picture kicking around in my phone. See the prop? It’s precisely where the sail drive would normally be. See the little splash of yellow in the middle of all of the black? That’s the edge of the hole. The forward edge.

So I created a well above that, it house is a 30 hp outboard on slides. So I can lift it all the way up to deck level or slide it down like it is in the position that you see in this picture. When I’m sailing I plan to pull them up to reduce drag. When I am motoring with just one I pull the other up to reduce drag.

So the problem I’m having is the Outboards sit on a bracket on the slide. I had made temporary brackets for the slide a long time ago out of wood and epoxy and they rotted away.

They actually fell apart after rotting away. The Outboards dropped down when I wasn’t around and landed in the well.

So from the pieces of the rotten wooden ones, we tried to put together the precise dimensions of the new ones that we made out of pre-fabricated extruded fiberglass. There was a whole thread about making these.

Anyhow, the fiberglass didn’t have the stiffness that the wood did. So it was a little Bendy where the Outboard clamped on.

We had to double up the thickness to get more stiffness. And that added half an inch. And that half an inch is precisely what’s screwing the clearance up. I didn’t realize I used such perfect tolerances for those Outboards to stick through the hole. Good for me for keeping drag down.

Given all of the options, slightly increasing the size of the hole that the outboard sticks through is the best solution. Just shaving half an inch off the aft part of this hole. The boat is at a dock in the water. So, it can’t move anywhere without the engines. So I need to lift it up a little bit, grind out half an inch from the back portion of the hole, de-core and fill the edge with thickened epoxy. A job for my helper and I’ll be fine because it’ll go under water after he’s done.

That way the Outboards will be able to slide through the hole again.

Now, in the big thread about building the outboard mount brackets, One of my chief complaints was that these used to transmit an incredible amount of noise to the hull and it was just awful. This boat was so loud. I have 1000 nautical miles on the boat. And that’s all under engine and my God it was not pleasant. It was so loud.

The new mounts have made it so quiet that you can have a whispering conversation anywhere in the boat and you don’t even have to struggle over the sound of the engines anymore. We put sound dampeners and vibration dampeners into the motor mounts this time and it is absolutely fantastic. So the result of that large thread really came out good. Even though the Outboards didn’t make it all the way through and hung up on the cavitation plate, I was still able to start them to test them and they were absolutely quiet. It was really nice.
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