MONTAUK 17 Swamped Stability

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MattFL
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MONTAUK 17 Swamped Stability

Postby MattFL » Mon Apr 22, 2019 11:42 am

To anyone who has been in a swamped classic Montauk 17: please Comment on how stable a swamped MONTAUK 17 is in regard to the hull wanting to roll.

This is just a curious question after witnessing a non-Boston-Whaler 16-to-17-foot boat sink right in front of me a couple weeks ago. The wind had turned the boat so the stern was facing the waves. As we were trolling away the other boat took a wave over its stern. That put enough water in the boat that every-other-wave start coming over the transom. The guys on the other boat started screaming for help. We pulled up as the other boat was going under. From the first wave until the other boat was under water took about two minutes.

That got me thinking. I know a Boston Whaler won't "sink", but it sure will roll over. If that were us who took a wave or two over the stern, putting six-inches or more of water in the MONTAUK 17, would the MONTAUK 17 become so unstable that it would likely roll over?

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Phil T
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Re: MONTAUK 17 Swamped Stability

Postby Phil T » Mon Apr 22, 2019 12:32 pm

The key element I learned is not to move around in the boat quickly and change the balance of the boat. Once it starts to tip, it gains momentum and that can lead to shipping more water and possibly capsizing.

In my case I did not loose power, fortunately I was able to turn into the wind and dewater.
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1992 Outrage 17, 1992 Evinrude 115

jimh
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Re: MONTAUK 17 Swamped Stability

Postby jimh » Mon Apr 22, 2019 5:24 pm

I have not been aboard a swamped MONTAUK 17 boat. I am sure there must be someone who has.

MattFL wrote:...comment on how stable a swamped MONTAUK 17 is in regard to the hull wanting to roll.

Any boat that has a lot of water that is free to move from side to side within the hull of the boat will have reduced roll stability.

An element of the Boston Whaler that affects the ultimate roll stability when the boat is swamped is the double-bottom construction. The reserve buoyancy of a Boston Whaler boat that makes it "unsinkable" is produced by the reduced open volume inside the hull that cannot be filled with water because it is filled with foam. There is not as much open space in a Boston Whaler boat to collect water within the hull. With less open space for water to collect and move around, a Boston Whaler boat will tend to have better swamped stability because of the reduced volume of water it can hold. This is also why the boat won't sink.

Last summer I was aboard a 15-foot Boston Whaler that had an unusually large amount of water in the cockpit that was free to slosh around. The lateral stability of the hull was very noticeably affected. The four crew had to be extremely cautious with their movement in order not to have the hull roll too far to one side.

The round bottom of the classic MONTAUK 17 hull is similar to the 15-foot hull. The MONTAUK 17 would likely have a similar tendency to roll with a large amount of water aboard.

A hull bottom shape with a completely flat bottom and vertical hull sides should have the most initial roll resistance. A hull with a rounded bottom would have the least roll resistance.

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jimp
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Re: MONTAUK 17 Swamped Stability

Postby jimp » Tue Apr 23, 2019 5:26 pm

Back in 1990 or so during my Coast Guard days in Kodiak. I flooded my 1982 Montauk with 90-HP Evinrude at the dock.

It was a beautiful day! A great day to work buoys. I had the Montauk moored with short lines to a float on the leeward side of the ship pier, out of the wind. We always moored our small boats there. So we got the ship underway and worked a buoy or two and the weather started picking up unexpectedly – winds up to 35 knots, a little squall coming through. I didn’t think much of it as we headed in. After mooring one of the guys came up to me and mentioned that the Whaler was full of water. Huh? So I walked to the other side of the pier and *^(&^$%$&^)*. It was true. The steep 2-ft seas were wrapping around the pier and with short, tight lines the stern, that was to the waves, was shipping water.

So I ran down to the float and cast the stern line off and pushed the stern off the float to get the stern downwind and the bow upwind, but still secured to the float. The coolers and tackle box were floating around and the battery box was underwater. I had the bilge pump off. First thing, energize the bilge pump but that was immediately overpowered by the water because with me in the boat I was still shipping water. So I pulled the plug

At this point, the boat was “loggy”, slowly rolling in the direction I was moving. Standing midships was the best and as Phil T mentioned, moving slowly. What to do? Put the key in the ignition and turn it to see what happens. With a roar the 90 fired right up. Easiest way to drain a 13-ft Whaler as a kid (1966-1981)? Pull the plug and go. So still somewhat sheltered behind the pier I cast off an added power, bow came up and water dumped out, more throttle, keep going, 5 minutes later return to the float, all dry and tie up.

As an aside, I was surprised the engine started with the battery box underwater. So, I took a look. The battery box cover hangs down over the sides of the battery box and that traps air inside the cover. The battery terminals were dry and there was an inch or so of water in the bottom of the battery box. Some battery box covers have vent holes in the top for use in an enclosed area. I had taped mine over as the box was out in the weather.

MattFL
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Re: MONTAUK 17 Swamped Stability

Postby MattFL » Wed Apr 24, 2019 9:28 am

JIMP--thanks for sharing your story [of a swamped MONTAUK 17].

It sounds like these [Montauk 17] boats aren't so unstable when heavy that they want to roll over by themselves without some external forces applied such as waves or people running around.

A feature of a [Boston Whaler Montauk 17] that concerns me is the limited ability for removing water quickly: one small bilge pump and one small plug.

I pulled the plug on my boat at the dock to see where [the water coming into the boat] would [rise to and then] equalize. With a light load [the Montauk 17 boat] floats so high that only the tunnel has water in it and the deck is dry.

Thus, in theory, if you pull the plug and keep [a Boston Whaler Montauk 17 boat] upright, [water in the cockpit] will eventually drain. But that could take some time.

I had an old Hobie 15-foot boat--not a quality boat--but it had a pair of 3-inch scuppers at the rear for draining the deck. On day we ducked [the Hobie 15-foot boat] under a wave in the inlet--one of those things you never forget. The [Hobie 18] boat [was] very flooded and by some small miracle still upright. I just kept the throttle open and --wow--did it drain fast through those big holes. Hobie must have used big holes to try to make up for the lack of seaworthiness of the rest of the boat.

Another day in the ocean while bouncing through some waves there was a loud CRACK sound. Then every other wave was another crack. So we slowed to a crawl and made it back. One of the stringers had burst and the bottom of the boat was now super flexible--why my next boat was a Boston Whaler boat with solid foam and no stringers. I called our insurance company to ask if this was covered. They asked what happened, I said, "we hit a wave and it broke." They said ,"well you do have collision coverage so it's covered", and they totaled the boat and paid the claim.

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Re: MONTAUK 17 Swamped Stability

Postby jimh » Wed Apr 24, 2019 10:57 am

MattFL wrote:It sounds like these [Montauk 17] boats [when heavy] aren't so unstable...that they want to roll over by themselves without some external forces applied such as waves or people running around.


I don't see the MONTAUK 17 as being particularly special in that regard. In any boat, when water is coming board, as long as the arrangement of open spaces in the hull where the water can collect is symmetrical about the keel, the water weight will remain symmetrically distributed. The weight of the water will be acting equally on each side, and the hull should not roll. The tendency for a hull to roll only occurs when the weight is not distributed symmetrically about the keel centerline.

MattFL wrote:...in theory...if you pull the plug and keep [a Boston Whaler Montauk 17 boat] upright, [water in the cockpit] will eventually drain.


The ability of a Boston Whaler boat to drain water in the cockpit to the sea is not a theory. It will occur anytime the water level contained in the cockpit is higher than the waterline of the boat.

MattFL wrote:A feature of a [Boston Whaler Montauk 17] that concerns me is the limited ability for removing water quickly: ...one small plug.


The rate at which water will flow through a limited diameter discharge pipe depends on the pressure at which the water is being pushed through the limited diameter pipe. As you observed in your narrative of your experience with another boat brand, the larger the diameter of the discharge pipe the more easily water can flow through the pipe. But that works in either direction. If a Boston Whaler had a 3-inch diameter hole though the deck to the hull bottom, then water would come aboard through that opening at a faster rate.

In the case of the Boston Whaler 17-foot hull, the hull has been in production since 1961 or for 58-years. If there were any particularly dangerous behavior of the hull when the cockpit was flooded or if there were a particularly bad design in the size and position of the cockpit sump drain, the hull would likely have attained some reputation for these undesirable characteristics, and those flaws would be widely known and remarked about by owners.

macfam
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Re: MONTAUK 17 Swamped Stability

Postby macfam » Thu Apr 25, 2019 9:23 am

A 170 Montauk on a dock nearby had rainwater accumulate after several storms last year. It was holding about as much as the hull would hold. The rear end tends to squat when filled, and the water was just about flowing in and out over the transom. Obviously, the bilge pump was no longer working. It probably never worked when the storms started.

I gently stepped aboard at the bow, and made my way aft. The balance was so squirrelly, I stepped over the console and seat to get to the sump, and stayed as much to the centerline as possible for balance, and pulled the plug. Then ever so gently made my way back to the bow area. No way could I have done this comfortably fully clothed. I was in a bathing suit.

The boat drained nearly completely except a wee bit on the floor and a full sump.

In my opinion, the balance is VERY touchy when there is a large volume of water inside. One cubic foot of water weighs about 62 pounds.

Older Whaler advertisements had six or seven employees standing in a swamped Montauk. It must have been a challenging balance feat.

This was on a dock with calm water. If this were to happen in two-foot or higher seas, then MAYBE without the loss of power, and heading into the seas, you could de-water over the transom and eventually gain total control. However, if there were no power, and the seas and wind take control, [inverting] would be the common result.

But to know the hull won’t sink is good. That can save your life.

MattFL
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Re: MONTAUK 17 Swamped Stability

Postby MattFL » Thu Apr 25, 2019 11:03 am

That [the 170 MONTAUK described in the preceeding article] wanted to remain upright, even if very tipsy, is good.

My thought was if the center of gravity when flooded were too high, [the huill] would become inherently unstable and refuse to stay upright without external inputs keeping it balanced.

I guess once you have a fully flooded boat the odds are against you anyway, but it's nice to know that it at least doesn't object to being upright.

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Re: MONTAUK 17 Swamped Stability

Postby jimh » Thu Apr 25, 2019 4:23 pm

Re the mention of the location of the center of gravity of a flooded hull: in that regard the Unibond hull of a Boston Whaler that is flooded may have a higher center of gravity compared to a conventional hull. The weight of the water in the Unibond hull is being maintained at a higher position in the hull compared to a conventional hull in which the water would be flowing into the deepest parts of the open bilge of the hull. In the Unibond hull the water is above deck level, whereas in a conventional boat the same volume of water would likely be below deck level.

I recall reading an account of a very expensive custom built sailing yacht that was making its first long distance voyage. It was built in Europe and was being sailed to North America. The boat was hundreds of miles out to sea when something broke deep in the hull, but went completely unnoticed. The boat began to take on seawater. The crew were all on deck, enjoying a nice day of sailing. They did not notice anything odd about the behavior of the boat as it became more and more filled with water. Finally someone on the crew went down the cabin steps and discovered the cabin sole was under water. The engine was already flooded. They could not get any pumps going to dewater. They could not find the source of the leak. The hull eventually held so much water than it lacked buoyancy and sank--a complete loss of a multi-million dollar yacht. The crew abandoned ship to life rafts. But the lateral stability was fine all that time.

At least with a Unibond hull if a lot of water comes aboard it will be immediately apparent and the crew can take action to dewater the boat.

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Re: MONTAUK 17 Swamped Stability

Postby Guitarfish » Sun May 12, 2019 11:51 am

On MONTAUK 17 stability: years ago I learned a lesson through an incident that occurred to another fishing club member while he was fishing in his Montauk 17. This incident began with zero water ingress reported aboard. There were three on board. Angler #1 and #2 were in an aft corner in the act of netting a fish. Angler #3 moved alongside them to see the fish. The stability was instantly upset and the boat flipped. They spent hours in the cold Pacific riding the hull until a commercial boat spotted them.

As captain of my own boat, I always have a pre-trip talk about how to find or use everything: radio, first aid kit, Life-Sling, dry clothes, flares, that you had to wear a life vest at all times, and movement about the boat were all discussed.

I still had a few sudden people-induced tilts when docking. Any of our small Whalers will flip, full of water or not.

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Re: MONTAUK 17 Swamped Stability

Postby jimh » Mon May 13, 2019 10:04 am

Guitarfish wrote:Any of our small Whalers will flip, full of water or not.


The lateral stability of the Boston Whaler 13, 16, and 17-foot hulls is extraordinary compared to most other boats. These hulls have been in production for almost 60 years. If these Boston Whaler boats exhibited a tendency to be prone to frequent and unanticipated lateral rolling and inversion of the hull, I doubt that Boston Whaler could have remained in business for almost 60-years making these boats.

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Re: MONTAUK 17 Swamped Stability

Postby Jefecinco » Mon May 13, 2019 10:12 am

For a Montauk 17 to flip with three anglers in an aft corner I believe some extreme external force would have to have been in play. Even if the boat only rolled an external force would be needed. Perhaps a wind and or sea related force of some magnitude would be required. I don't doubt the report although I question it's accuracy.
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MattFL
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Re: MONTAUK 17 Swamped Stability

Postby MattFL » Mon May 13, 2019 10:49 am

We've had several people run to the same side in my 17' and it has definitely led to some exciting moments, but I don't recall it rolling far enough to actually take any water over the side. For it to roll completely over inverted I would guess those must have been some fairly hefty dudes and/or rough water.

Guitarfish
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Re: MONTAUK 17 Swamped Stability

Postby Guitarfish » Mon May 13, 2019 11:42 am

The info I heard was indeed third party, but can say that angler #3 was reported to be a big guy. I don't recall hearing of sea conditions but I'm sure that a swell likely contributed.

To be clear, I was not disparaging BW hulls. I simply meant that anything is possible given the right situation. If it is possible to flip a dry hull it stands to reason that the hull would certainly be less stable swamped. I probably should have stated my opinion in that way.

I am obviously a Boston Whaler owner because of its well earned reputation and 14 years of ownership experience at this point. I have no experience with the 16 hull shape of my Menemsha yet, but I will be hitting the Pacific soon. I do have some experience with larger model passengers so will practice due diligence.

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Re: MONTAUK 17 Swamped Stability

Postby jimh » Tue May 14, 2019 9:29 am

The effect of movement of crew weight on the trim of a boat is determined by the total weight of the crew that has moved in comparison to the total weight of the boat. In the case of a MONTAUK 17 boat, the hull weighs only 550-lbs. If the crew consists of three adults that each weigh 200-lbs, then the total weight of the crew is greater than the weight of the hull.

That movement of 600-lbs of crew weight to be concentrated in a small area at the gunwale at the stern in a boat hull that only weighs 550-lbs would have a significant effect on the trim of the boat should not come as a surprise to anyone who is familiar with mono-hull rounded-bottom-hull boats.

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Re: MONTAUK 17 Swamped Stability

Postby macfam » Sat May 18, 2019 5:54 pm

jimh,
Double check on that Jim.
The 17 Montauk is actually 950 lbs.

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Re: MONTAUK 17 Swamped Stability

Postby jimh » Sat May 18, 2019 7:50 pm

Hull weight varies with year and model.

BillFarrel
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Re: MONTAUK 17 Swamped Stability

Postby BillFarrel » Tue Nov 26, 2019 4:50 pm

I have been concerned about [the stability of a hull after it has been swamped with seawater] since acquiring a Montauk 17 several years ago.

My background was sailing in SF Bay when younger in International 14's. Swamping and rolling over was a daily experience. Slide over the rail, stand on centerboard and pull the boat back up. Apply sail power and if all goes well, water goes out the open transom. Over course, a lot of water in the boat makes the thing totally unstable and as you go back into the boat to right it, your weight and the crew's often cause the boat-full of water to flood your way and the boat rolls onto you. Real quick. So around to the opposite side and try again.

I fish in-shore in Monterey Bay and it is often be very choppy with large swells. Lots of wind. The MONTAUK 17 freeboard at the transom is only about 6 inches (like most small power boats) and as soon as you stop to fish the heavy motor and light higher bow cause the bow to swing downwind. The waves slop right up to the top of the transom cutout quite often. I have not taken a load of water into the boat, but worry about it. So I usually tip the motor up and throw out the drift anchor. This bring the bow around and a much safer ride,- more comfortable too. If the motor is not raised to get the shaft out of the water, boat will maintain a sideways position to the wind with lots of rolling around as seasick passenger.

One good wave over the stern will set up for more of the same, in rapid order, and you have to assume the boat will fill to the top of the transom cut out. I think at that point it will become very laterally unstable. Older Whalers are narrow, have a fair amount of dead rise, and have vertical sides. This is a much less stable arrangement that either an 18-foot banks dory I previously owned, or the 18-foot Klamath tinny I had. The Klamath was flat bottomed with flared sides like a dory. Like the dory, the more weight you put on the rail - passengers all on one side, the more it stiffened and resisted further rolling.

The Whaler does not have this reserve bouyancy and has low freeboard to boot. So, I am very particular with others on board about boat trim. When one guy goes starboard, I go port. Fore and aft trim the same. It feels like a sensitive design to me and one where balance needs to be paid attention to. I don't think it is unsafe, is attention to balance is paid. I have heard of several guys rolling over in Montauk's while trying to pull up crab pots. Two guys on one rail, with a hoist. Not the right boat for that.

I liked the comments on how to de-water a flooded Montauk. But I would note that in conditions where one takes a load of water over the stern the boat would likely be position stern to weather. The motor will need to be started, and the boat turned 180 degrees in rolling waves to get headed up-wind to dump water over the transom. Sounds dangerous and challenging if conditions are bad. Obviously, one should head-in at first indication that the wind is starting to rise. I think going miles offshore in the ocean in a little boat like this has to be a very risky endeavor, no matter how skilled the operator. I am old and cautious and pay constant attention to the boat, its position and the waves.