170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
bmat5
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170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby bmat5 » Mon Jul 12, 2021 8:40 pm

My 2005 170 Montauk will be spending summers in a slip on Barnegat Bay. The boat hasn't been previously bottom painted. I've read various threads on this topic; I still have questions.

I assume [other than anti-fouling paint] there is no other viable method of keeping a [hull in the water and below the waterline] clean and free from [marine growth] when sitting in a slip.

I don't mind taking the boat out for a good cleaning every three weeks or every four weeks.

I've noted one product—VS721—which gets good reviews. Give me advice about VS721.

I have someone to prepare, prime, and paint. He wants me to jack [up the boat] enough to set [the hull] on blocks, or place some small wood blocks between the hull and trailer bunks. I'm a bit nervous about lifting [the boat off the trailer bunks].

Q1: What is the best method for lifting the boat without the benefit of over head support or using the lifting hooks?

Q2: Should I use a floor jack with wood against the gelcoat surface?

Q3: If so, what are the strongest jacking points at the bow and stern?

Someone suggested using the trailer as a lever by lowering the tongue all the way down to raise the stern, then block underneath, then raise the tongue all the way up to block at the keel nearer the bow.

Q4: If advisable, where are the strongest points to support and block the boat from underneath?

Q5: Are epoxy primer and anti-fouling ablative the way to go?

I've read comments on performance loss, and requiring re propping. That would be a deterrent to painting.

Thanks for input

jimh
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Re: 170 Montauk bottom painting and lifting

Postby jimh » Wed Jul 14, 2021 8:33 pm

The keel is the strongest part of the hull bottom. Any mechanical lifting force applied to the hull from below should bear on the keel.

For advice on anti-fouling paint and hull epoxy sealing coat, read the owner’s manual.

Anti-fouling paint performance seems to vary by region. Consult some local well-informed boaters for recommendations on best anti-fouling paint.

Use of an epoxy paint as an undercoat before applying anti-fouling paint is not really as a primer paint. The purpose of the epoxy barrier paint is to create a true waterproof layer between the water and the fiberglass.

jimh
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Effect of Anti-Fouling Bottom Paint on Boat Speed

Postby jimh » Thu Jul 15, 2021 9:38 am

On a corollary topic:

Effect of Anti-Fouling Bottom Paint on Boat Speed

See

https://continuouswave.com/forum/viewto ... f=7&t=6576

bmat5
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby bmat5 » Thu Jul 15, 2021 1:56 pm

Thank you Jim. The keel is very defined forward toward the bow, yet seemingly a lot less defined and almost flat at the transom. I interpret your reply to mean it is the strongest point forward and aft. Please confirm and thanks again.

Oldslowandugly
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby Oldslowandugly » Thu Jul 15, 2021 10:59 pm

It hurts to paint a clean unpainted hull. Hauling the boat and power washing works. But barnacles are a problem and must be scraped off.

I used to lift the boat off the trailer with a bottle jack. It slipped once and scared me to death. Now I use two cradles I welded up from some street sign poles I "found". I can lift at each corner a little at a time safely. I set the cradle on cement blocks. Now I can paint underneath in safety.

I like an ablative paint that wears away. You don't need to strip the old stuff off.

IMG_1020.JPG
IMG_1020.JPG (229.77 KiB) Viewed 588 times

jimh
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby jimh » Sat Jul 17, 2021 7:09 am

bmat5 wrote:I interpret your reply to mean it [that is, the keel of the hull bottom] is the strongest point forward and aft. Please confirm...


I confirm that my earlier statement (that the keel is the strongest point of the hull for lifting upward with mechanical means from below the hull) is apparently being correctly interpreted by you.

Since on the particular hull that is the topic of this discussion there is no clearly formed keel in the aft portion of the hull bottom, you can interpret the term "keel" to mean the centerline of the hull in the aft portion of the hull which has a rounded bottom.

jimh
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby jimh » Sat Jul 17, 2021 7:13 am

bmat5 wrote:I assume [other than anti-fouling paint] there is no other viable method of keeping a [hull in the water and below the waterline] clean and free from [marine growth] when sitting in a slip.


Another method for protecting a hull from marine growth while made fast to the dock at a marina is to construct a submerged enveloping barrier around the hull, then fill this with freshwater which you treat with a marine growth inhibitor. I have seen a technique like this used on 12-meter racing sailboats during America's Cup competition. I don't think it is a very practical method for a boat being kept in a rented slip at a marine.

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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby jimh » Sat Jul 17, 2021 8:04 am

bmat5 wrote:I don't mind taking the boat out for a good cleaning every three weeks or every four weeks.


I am not clear on the meaning of "taking the boat out for a good cleaning..."

Do you mean hauling the boat from the water to clean the hull bottom?

If so, then an interval of three or four weeks may be too long to catch marine growth at a stage where the marine growth can be easily removed from the hull with just a casual scrubbing. Again, this will depend on the particular water in which the boat is being kept. If in cold flowing seawater, perhaps an interval of two weeks or slightly longer would be workable. But in warm and stagnant seawater, a week of marine growth may already become difficult to remove.

Or, do you mean getting the boat underway at high speed to scrub off growth from the bottom? That method might work if the local water was not particularly conducive to rapid marine growth.

macfam
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby macfam » Sun Jul 18, 2021 12:58 pm

Bmat5--if you were near Cape Cod I’d let you borrow my Brownnell Boat Lifting System. It works like a charm.

https://boatstands.com/product/manual-boat-lifting-system/

dtmackey
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby dtmackey » Mon Jul 19, 2021 11:49 am

Back around 1995, I used an engine crane and a backhoe to lift my MONTAUK 17 and put the hull on blocks.

Image

D-

jimh
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby jimh » Mon Jul 19, 2021 12:47 pm

Certainly the best method for lifting a MONTAUK from above is to use the lifting eyes provided in the hull. And this method would be perfect for bottom painting as none of the hull bottom would be obstructed from access for painting. CAUTION: the painter would be below the boat and would have to have confidence in the hoisting method.

Unfortunately, however, the information being sought by the thread originator specifically asks for advice for lifting "without overhead supports."

But there is a method that will be perfect:

  • remove the engine, the fuel tanks, and all loose gear
  • raise boat vertically several feet using best method available
  • rotate boat 180 degrees along the longitudinal axis
  • set boat down onto two support beams that sufficient high off the ground to allow the windshield and any other structures to clear
  • paint bottom without any obstructions
  • when paint is dry, reverse procedure to get boat back on trailer

bmat5
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby bmat5 » Wed Jul 21, 2021 9:59 pm

I'm not clear on the meaning of "taking the boat out for a good cleaning..."

Do you mean hauling the boat from the water to clean the hull bottom?

If so, then an interval of three or four weeks may be too long to catch marine growth at a stage where the marine growth can be easily removed from the hull with just a casual scrubbing. Again, this will depend on the particular water in which the boat is being kept. If in cold flowing seawater, perhaps an interval of two weeks or slightly longer would be workable. But in warm and stagnant seawater, a week of marine growth may already become difficult to remove.

Or, do you mean getting the boat underway at high speed to scrub off growth from the bottom? That method might work if the local water was not particularly conducive to rapid marine growth.


Jim,
I was referring to taking the boat out of my slip every couple of weeks, for a week. This boat will be in a slip, in a lagoon, on the Barnegat Bay in NJ. Given there is a nearby by public launch, I could retrieve it after a couple of weekends of usage, and return to the trailer for a thorough cleaning, until the following weekend. Maybe not the most practical, but not terribly difficult as well. I'm still evaluating.

jimh
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby jimh » Wed Jul 21, 2021 10:15 pm

bmat5 wrote:
I'm not clear on the meaning of "taking the boat out for a good cleaning..."

Do you mean hauling the boat from the water to clean the hull bottom?

If so, then an interval of three or four weeks may be too long to catch marine growth at a stage where the marine growth can be easily removed from the hull with just a casual scrubbing. Again, this will depend on the particular water in which the boat is being kept. If in cold flowing seawater, perhaps an interval of two weeks or slightly longer would be workable. But in warm and stagnant seawater, a week of marine growth may already become difficult to remove.

Or, do you mean getting the boat underway at high speed to scrub off growth from the bottom? That method might work if the local water was not particularly conducive to rapid marine growth.


Jim,
I was referring to taking the boat out of my slip every couple of weeks, for a week. This boat will be in a slip, in a lagoon, on the Barnegat Bay in NJ. Given there is a nearby by public launch, I could retrieve it after a couple of weekends of usage, and return to the trailer for a thorough cleaning, until the following weekend. Maybe not the most practical, but not terribly difficult as well. I'm still evaluating.


I understand your reply to mean you would haul the boat out of the water for cleaning. See my comments above for that situation.

Oldslowandugly
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby Oldslowandugly » Wed Jul 21, 2021 10:36 pm

If you are in Jersey you will find the same kind of growth I find in New York.

Procedure:
  • Go to the area where you will be docking the boat.
  • Take something that you can tie a rope to and submerge it there; a bucket will do.
  • Come back once a week and lift it out so you can see what develops.

We get green algea, slime, seaweed, and barnacles.

I bottom paint the boat.

At end-of-season a power washer easily gets off the green stuff.

A power washing every couple of weeks would probably work.

If barnacles take hold they are a real pain.

jimh
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby jimh » Thu Jul 22, 2021 9:29 am

How much anti-fouling paint will be removed with a bi-weekly power washing of the hull bottom?

I would think after three months and six power washings of the hull, there would not be much bottom paint left.

Also, use of a power washer tends to force water into the gel coat. I don’t think bi-weekly power washing is a particularly good practice for caring for a fiberglass boat.

Oldslowandugly
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby Oldslowandugly » Thu Jul 22, 2021 10:51 pm

How much anti-fouling paint will be removed with a bi-weekly power washing of the hull bottom?
None [because the boat being power washed would not have bottom paint.]

I don't mind taking the boat out for a good cleaning every three weeks or every four weeks.

[Every three or four weeks] is too long to wait [between hull bottom cleaning on a hull] with no anti-fouling [hull bottom paint]. Two weeks is even pushing it around here.

A power washer can have several nozzles. The "soap" nozzle is a very low-PSI setting. [The water stream from that setting] won't hurt anything. I even use that on the decks.

Since my boat had a poor history of bottom paintings I then use the “general purpose" nozzle on the bottom in the Fall. It tends to remove any loose paint that I would otherwise have to scrape off.

As much as it would bother me to paint an unpainted hull, [anti-fouling bottom paint] is the best answer to the fouling problem.

I advise first [applying ] a barrier coat. That way you prevent osmosis: where water gets under the gel coat and causes blistering. [A barrier coat]also makes a great base for underwater primer, which is then followed by the anti-fouling paint of your choice.

Interlux makes several great products to do the whole job from beginning to end.

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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby jimh » Fri Jul 23, 2021 8:41 am

Oldslowandugly wrote:A power washer can have several nozzles. The "soap" nozzle is a very low-PSI setting. [The water stream from that setting] won't hurt anything.
If you use a pressure-washer on a setting that has little or no pressure, would just using a hose with a conventional nozzle do the same job?

Oldslowandugly
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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby Oldslowandugly » Fri Jul 23, 2021 10:35 am

A low pressure nozzle is much stronger than a hose. It has enough pressure to dislodge stubborn dirt and sea growth. It is also the setting that is required to use with a soap siphon. You run the siphon hose from the power washer into a container of soap solution and it draws it in and mixes it with the pressurized output. The higher pressure nozzles will not siphon the soap.

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Re: 170 Montauk: Lifting Hull Off Trailer Bunks to Paint Bottom

Postby fno » Sun Jul 25, 2021 10:53 am

Back to the original question: I have lifted my 160 Dauntless off of the trailer in my driveway. I used the tow eyes on the rear to secure the boat to a tree and pulled the trailer about 24 inches forward to expose the rear end of the boat. I then used a floor jack to lift at the keel with a block of wood in between about 1-2" off the trailer. Jack stands (think Harbor Freight or Northern Tools) are placed under the stern to support the rear end of the boat. The jack can then be used to lift the bow end of the keel and a third stand placed under it. Take care that the location of the bow support may need to be changed as you pull the trailer out and in. Two jack stands up front will accomplish this. Another thing to note: raise the motor all the way up. In the unlikely event that you drop the boat, repairing the fiberglass will be the least of your worries compared to replacing the lower unit on your outboard. I've seen that scenario play out before, not by personal experience.