Landing a Big Fish on a 190 NANTUCKET

A conversation among Whalers
Yuk
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Landing a Big Fish on a 190 NANTUCKET

Postby Yuk » Mon Aug 01, 2022 9:38 pm

Is a 190 NANTUCKET boat gunwale physically strong enough to handle landing a big fish?

LONG BACK STORY: My father has a 190 NANTUCKET. As a kid we used to go to Stellwagen bank in the 190 NANTUCKET on nice days for cod fishing. I am dreaming of a solo Nantucket sleighride in a Boston Whaler on a calm day just for the fun of it. Looking at the gunwales [apparently on his father's 190 NANTUCKET] this weekend while striper fishing, I thought to myself. "this boat needs a pair of vertical rod holders just behind the rearward factory urod holders." Now I am thinking, is this gunwale strong enough? I would use a nice Gemlux rod holder with backing plate.

ASIDE: These days I fish the bank pretty heavily in a larger 28 SOUTHPORT.

{Moderator's note: this article was appended to another thread on another topic in which the question of the strength of the boat to be able to land big fish was NOT the topic. Please do not revive old discussion and then change their topic. Your article on this new topic has been moved to a new forum for discussion of your new topic.}

Jefecinco
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby Jefecinco » Wed Aug 03, 2022 9:36 am

Have you considered adding rod holders to the bow rail? Good quality rail mounting clamp-on rod holders made of stainless steel are available for reasonable prices. The installation is easy and takes little time. They offer versatile mounting attitudes and are easily moved. I have used them for several years and found them to be a useful addition to our boats.

The two major advantages to their use is they have no effect on gunwale integrity and require little effort to install.
Butch

jimh
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby jimh » Wed Aug 03, 2022 10:16 am

I don't understand the concern about the strength of the gunwale on a 190 NANTUCKET vis-a-vis a fish's weight. The gunwales of all Boston Whaler boats are routinely used by adult humans whose weight exceeds 200-lbs and who step directly on the gunwale when boarding the boat with all their weight on one foot. This means a weight of 200-lbs is concentrated on the gunwale in a small area equal to the toe tread of a shoe. Adult humans also routinely sit on the gunwale of Boston Whaler boats, often more than one or two at a time in close spacing.

Exactly how much weight will "a big fish" exert on the gunwale that there is concern that the structure of the gunwale will be damaged?

Jefecinco
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby Jefecinco » Thu Aug 04, 2022 10:09 am

I suspect the poster/s concern is with the lever effect of the rod and the pressure exerted on an embedded rod holder in the gunwale.

A large fish such as a shark has a high strength pull on the top of the rod which is part of the lever. The length of the rod would make a difference. Typically, offshore fishing rods are shorter than rods used to catch smaller fish. I accidentally hooked a shark in Mobile Bay fishing with 60-lbs-test braid line. It took the shark only about five minutes to break the line. The rod I was using was bending and the drag on the reel failed to turn the shark. After the encounter the reel was noticeably hot. I believe the pull was well over 100-lbs.
Butch

Yuk
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby Yuk » Thu Aug 04, 2022 12:14 pm

What made me wonder about the strength of the gunwale was learning that the gunwale was attached [to the hull using an] adhesive from a drawing posted elsewhere in the forum.

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My plan is to install a pair of GEMLUX Screwless 0-degree rod holders. I like GEMLUX rod holders because there are no screw fasteners. There is a large nut on the underside. A large backing plate can be installed easily. See Figure 2 below.

GEMLUXrodHolder.jpg
Figure 2. The Gemlux screwless rod holder 0-degree version.
GEMLUXrodHolder.jpg (31.29 KiB) Viewed 100 times


With these rod holders I would use a tuna rod with a bent butt and a swivel. This would allow me to fight the fish from the rod holder while still staying close to the helm when boating alone.

My concern was how much force [the adhesive joint between the molded hull and the molded gunwale] could take with the rod acting as a lever.

I don't want to damage the boat or loose a expensive rod. I might be overthinking and overestimating the amount of force applied to the gunwale.

Jefecinco
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby Jefecinco » Fri Aug 05, 2022 11:42 am

As soon as you cut through the gunwale cap you will encounter high density foam. If the Gemlux rod holder is attached at the cap the stress you are speaking of will, I believe, be mostly exerted on the cap. The foam will provide some resistance to crushing. I simply don't know a thing about the strength of the foam but suspect it is considerable given it's density and containment in a sealed space.

If Boston Whaler offered gunwale mounted rod holders on the 190 Nantucket I would not be overly concerned with retrofitting the boat with non-OEM holders of similar design. If not, I would be very hesitant and hope to hear from owners who had installed similar rod holders.
Butch

jimh
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby jimh » Fri Aug 05, 2022 12:14 pm

Thanks for clarifying what you were asking about. I believe that your original question would have been much better stated and much clearer for readers to understand if you had asked this:

Q1a: What is the strength of the adhesive that attaches the gunwale to the hull in a 190 NANTUCKET?

Q2a: That is the strength of the gunwale molded component to resist a bending moment exerted by a rod holder that requires a hole of diameter 3.67-inches to be drilled through the gunwale and the rod holder is holding a tuna rod and there is a big fish on the line?

If you had asked those questions, I would have replied as follows:

Regarding the strength of the adhesive, I would expect that the entire length of the gunwale molded component is adhered to the hull with an industrial adhesive of very substantial strength. As I replied earlier, the gunwale is exposed to a bending moment by people stepping onto the gunwale or by people sitting on the gunwale. Unless you can point to some evidence that the gunwale on a 190 NANTUCKET has failed to remain attached to the hull, I don't think there is cause for worry about the strength of the adhesive. Also, a Boston Whaler boat has a ten year hull warranty, so if a gunwale became unattached to the hull due to failure of the adhesive under normal use--that is, not due to some high impact collision--I am sure it would be repaired under warranty.

Now for the ability of the molded component of the gunwale to tolerate a bending moment created a rod holder, I do not see any way to answer this in a casual manner. To know the answer would required more information than is available. The strength of the gunwale molded component would have to be known; then the effect of the very large diameter hole that was made into the gunwale would have to be carefully analyzed using some appropriate method, perhaps finite element analysis or some less sophisticated application of Static Force analysis.

When the material strength is known, then the bending moment must be known.

I believe a reasonable basis for the bending moment is the strength of fishing line. If a line rated to part at 100-lbs is to be used, then the force on the fishing rod tip should not be much more than 100-lbs. If the rod is a "short" rod, let us then say a four-foot rod. Now we have 100-lbs acting on a 4-foot lever. However the lever is not stiff, the lever bends. So we might say at the most the turning moment on the rod holder is 400-lbs.

As for using a backing plate, that only spreads the loading forces on the bottom of the rod holder. The top of the rod hold will be exerting all its force on a much smaller area. The backing plate is going to be more useful in resisting a direct upward pull on the rod holder. But a direct upward pull on the fishing rod is not resisted at all by a 0-degree rod holder. On that basis, do not count on the backing plate to add huge resistance to the turning moment.

The analysis will also have to take into account that the rod will be bent out of vertical. Some of the force will be bearing aft on the top of the rod holder, and some of the force will be bearing forward on the bottom of the rod holder.

A better approach to inserting a 0-degree screwless rod holder into the gunwale of a 190 NANTUCKET which will be catching very large tuna on a fishing rod and line may be as I will describe below:

METHOD TO INCREASE RESISTANCE OF MOLDED GUNWALE TO TURNING MOMENT OF ROD HOLDER HOLDING FISHING ROD WITH LARGE TUNA ON THE LINE
  • Using a circular abrasive cutting tool like a Dremel tool, cut through the gel coat area of the gunwale gel coat layer creating a rectangular cut-out;
  • using some appropriate method to be developed on the spot, carefully remove the rectangular cut out section, including any foam that remains adhered to it
  • using a tool such as a chisel, remove the foam in the cut out rectangular area to a suitable depth to allow additional internal reinforcement materials, possibly wood or melamine board, to be placed into the recess that has been created
  • refit the gel coat rectangular section to test that it fits without interference, and adjust as need;
  • when satisfied with the fitment, use epoxy resin to coat and adhere the foam, the reinforcement, and the original gel coat piece together to form a very well adhered element concealed below the gel coat layer in the gunwale
  • install the rod holder
  • go fishing

A simpler alternative would be to fabricate two nice aluminum plates of say 0.25-inch thickness with rectangular shape. Add one plate on top of the gunwale and one plate below the gunwale. Then drill the big 3.67-inch hole though the two. Then drill the 3.67-inch hole in the gunwale. Mount the rod holder with a plate on top and a plate on the bottom. In this way all the turning moment forces will tend to bear on the aluminum plates and the plates will spread their load onto the molded gunwales.

Again, your original question in your post was only limited to strength of the gunwale to land "a big fish." Without your more recent clarification, it was difficult to infer exactly what you were asking about. To get good answer usually requires good questions.

jimh
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby jimh » Fri Aug 05, 2022 12:50 pm

By the way, if you land a really big tuna, say a 300-lbs fish, how do you plan to get it aboard the 190 NANTUCKET when you are out alone? Do you think you could deadlift 300-lbs of tuna over the gunwale?

Maybe you first should be thinking about cutting a tuna door in the hull. Note that cutting a tuna door will void the hull warranty. Boston Whaler only provides a tuna door on certain models and it the hull must be built and laid up specially to have a tuna door.

I guess all anglers are perpetual optimists.

Since you gave your backstory about fishing, I will give mine:

When I was a small boy our family used to rent a cabin on an inland lake for a week or sometimes two weeks, and the cabin always included use of a boat. My father would usually go out angling for fish after dinner. This was in the 1950's. No one had SONAR. My father did not have a nautical chart for the lake showing the bottom contour. His method was to go out in the boat an troll up and down about 150-feet off the shoreline and parallel to it, using artificial bait called flat fish. These devices wiggled when pulled at low speeds, and the rod tip would rock in harmony.

I wanted to go "fishing" with my father, so on occasion we would go out during the afternoon to troll along the shore. The success rate was very low. Most often the lure would snag on weeds. I would get excited thinking there was a big fish on the line. Dad would shut off the motor and I would reel in a big clump of weeds. As an eight-year-old, I soon figured out there was very little excitement to be had from angling.

I later figured out when I was much older that "fishing" for my Dad was a way to get out of the small cabin, away from the heat of the day, away from the kids, and be alone in a boat on a lake, and smoke a few cigarettes, which we were always pestering him to stop smoking. Catching a fish was an interruption to his solitude. If he did catch a Northern Pike or a Walleye, he would just release it. My mother did not like to cook fish, because she had only tried to cook fish from the supermarket that were probably a week old and smelled bad.

To this day, I am not particularly interested in angling for fish from my Boston Whaler boat. Many people see the boat and ask me something like, "How is the fishing?" I tell them I get all of my fish from the local fishery (Carlson's in Leland) and they are only $16-per-pound. If I tried to catch them myself they would be about $300-per-pound.

Also, the gunwales on my boat are not bolted on; they must be attached with an adhesive. I have never given them a second thought.

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Phil T
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby Phil T » Fri Aug 05, 2022 1:16 pm

Having consulted with four owners who had the gunwale caps on several post-classic designed-after-1990 models severely damaged, I would be hesitant to install a large rod holder like that without some significant modifications.

In addition to an aluminum backing plate underneath the gunwale, I would also install additional L-brackets forward and aft of the rod holder to provide more support. Mechanical fastening may be more desirable over high strength adhesives.
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jimh
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby jimh » Fri Aug 05, 2022 8:28 pm

PHIL--are you attesting to failures of the gunwale adhesive on a 190 NANTUCKET to hold the gunwale assembly in its original position as adhered to the hull as reported to you by actual owners of boats that had this happen?

Your proposed strengthening seem to be more focus on stabilizing the gunwale position on the hull than having the gunwale molded component tolerate the bending moment.

In order for a rod holder to break off the entire adhesive bond of the gunwale assembly from the hull, the material strength of the gunwale itself would have to be very much higher than the bond of the adhesive holding it to the hull. In many cases with modern adhesives, we have seen that the adhesive bond is often stronger than the material being bonded. I infer you are saying the adhesive bond is the weak link.

Jefecinco
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby Jefecinco » Sat Aug 06, 2022 10:26 am

This has been an interesting discussion. If I was a structural engineer and highly knowledgeable of Boston Whaler construction I could possibly add some value to the discussion. Given that I am neither of these I will add my conclusion. It is not a great idea for the original poster to install rod holders to his 190 Nantucket as he described.
Butch

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Phil T
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Re: Landing a Big Fish on a 190 NANTUCKET

Postby Phil T » Sat Aug 06, 2022 11:18 am

The incidents I refer to include:

a) Corrosion of the support bracket led to adhesive failure (2 incidents)
b) Installation of a pot puller without necessary support.
c) Improper use of a rod holder to secure the boat to a pier led to gunwale cap separation.
d) Loose gunwale cap, cause undetermined by new second hand owner.

In the cases above, I advised the owners on the options, techniques and materials to repair, reinstall the boat or redesign the installation.
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