1987 REVENGE 22 Hull Construction

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rnln
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1987 REVENGE 22 Hull Construction

Postby rnln » Fri Apr 08, 2022 2:30 pm

I own a 1987 REVENGE 22. Referring to Figure 1 below and Callout 1 and Callout 2:
  • I think Callout 1 points to stringers.
  • Does Callout 2 point to stringers?
stringers.jpg
Fig. 1. Portion of Unibond Hull of 1987 REVENGE 22 with callouts.
stringers.jpg (16.47 KiB) Viewed 1927 times

[Moderator's note: The image in Figure 1 has been reoriented to improve the intended purpose of the image as an illustration.]

padrefigure
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Re: 1987 REVENGE 22 Hull Construction

Postby padrefigure » Fri Apr 08, 2022 3:19 pm

[Figure 1] shows the aft [cockpit] well. This is [formed by] the hull [liner]. There is foam between the hull liner and the hull. In effect, there are no stringers.

The steps mirror the chines on the bottom of the boat, but not perfectly--there is no attempt to make the hull liner an exact inside copy of the outer hull.

These are merely details molded into the hull liner.

jimh
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Re: 1987 REVENGE 22 Hull Construction

Postby jimh » Sat Apr 09, 2022 7:51 am

rnln wrote:
  • I think Callout 1 points to stringers.
  • Does Callout 2 point to stringers?
None of the objects that can be seen and indicated by Callout 1 or Callout 2 are hull stringers. Callout 2 is pointing to something unseen on the starboard side of the hull. It is thus difficult to know to what other element Callout 2 is pointing.

You need to review the fundamental construction method for a Unibond hull. Read for comprehension at

https://continuouswave.com/whaler/reference/factory.html

under the subheading "Unibond Hull."

Read the patent that describes the unique hull construction method at

UNITED STATES PATENT OFFICE
U.S. Patent 3,013,922
MANUFACTURE OF PLASTIC ARTICLES HAVING
SPACED SHELLS WITH REINFORCED FOAM
FILLING


https://continuouswave.com/whaler/reference/originalPatent.html

In general there are no hidden longitudinal internal reinforcement structures embedded in the space between the hull and the hull liner in a Unibond Hull.

jimh
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Re: 1987 REVENGE 22 Hull Construction

Postby jimh » Sat Apr 09, 2022 8:11 am

fig2.jpg
Fig. 2. Callout 3 points to longitudinal elements molded into the hull liner.
fig2.jpg (15.49 KiB) Viewed 1923 times

Referring to Callout 3 in Figure 2 above, the formation of these two longitudinal elements creates the outer bulkheads of the in-deck live well* in the aft cockpit, and they also create the inner bulkhead of two rigging tunnels. By designing these structures into the hull liner mold, the structures add longitudinal stiffness to the overall hull structure. They perform a function similar to what might be called a stringer in conventionally constructed fiberglass boats.

The design of Boston Whaler boats generally incorporates a great deal of details and molded elements into the hull liner, such as rigging tunnels, hatch compartments, seats, coamings, gunwale caps,splash well bulkheads,the non-skid surface of the deck, drain channels, and so on. In certain area, both the hull mold and the liner mold will have embedded reinforcements adhered to the laminate structure, generally for the purpose of adding stiffness to panels and to provide wood or other material to hold threaded fasteners that will attach gear to the laminates.

--

* The compartment that is focus of this topic being identified as a "live well" might also be called a fish well or a wet well or a storage well or whatever anyone likes to call it, as the name has no real significance in explanation of the structural function served by these longitudinal bulkheads molded into the hull, which is the topic of this reply.

rnln
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Re: 1987 REVENGE 22 Hull Construction

Postby rnln » Sun Apr 10, 2022 6:21 am

Thanks Jim

padrefigure
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Re: 1987 REVENGE 22 Hull Construction

Postby padrefigure » Thu Apr 14, 2022 10:43 am

Callout 2 points to the outer wall of the rigging tunnel. As previously noted, not a stringer per se, but probably functions as a longitudinal stiffener in the hull design. These run from the rear bulkhead to the front of the console. There is an access plate in the floor that covers the end of these tunnels and provides access to the cavity below the console.

jimh
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Re: 1987 REVENGE 22 Hull Construction

Postby jimh » Sat Apr 16, 2022 9:23 am

One last comment (sent to me by a correspondent): the flat areas indicated by Callout 1 in Figure 1 above were likely intended to be the mounting bed for an inboard engine used with sterndrive propulsion for the 22-foot hull. In that application, perhaps the term "stringer" is quite appropriate.

Also, in looking more closely at Figure 1, I do not recall the four circular areas near the ends of those structures. I have looked into the livewell on my 22-foot hull many times, I cannot recall ever seeing anything but a smooth finished surface on the gel coat in the well. My hull was molded in 1990, but it used the sink splash well liner mold, as is also seen in Figure 1.

padrefigure
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Re: 1987 REVENGE 22 Hull Construction

Postby padrefigure » Mon Apr 18, 2022 5:50 pm

In my 1984 Outrage 22, the circles are present. I am not sure what they are--perhaps injection points for foam that are glassed over after set up? (Not likely as they seem to have gel coat in place and are recessed into the surface of the liner.) Or just rejection pin points for the liner mold? It is a mystery to me.

Vance's Revenge
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Re: 1987 REVENGE 22 Hull Construction

Postby Vance's Revenge » Mon Apr 18, 2022 10:24 pm

padrefigure wrote:In my 1984 Outrage 22, the circles are present. I am not sure what they are--perhaps injection points for foam that are glassed over after set up? (Not likely as they seem to have gel coat in place and are recessed into the surface of the liner.) Or just rejection pin points for the liner mold? It is a mystery to me.

The gelcoat on my 1980 Revenge 22 was chipping and cracked inside the circles so I was thinking they were injection points for the foam as well. They might have been used to ensure there was sufficient foam support for the mounting of an inboard? If this is true maybe the later models such as Jim's were smooth because the boat was no longer offered with an inboard outboard option? Just guessing of course.

I filled mine with Total Boat Total Fair and sanded them smooth so it would be easier to keep clean.


Vance

jimh
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Re: 1987 REVENGE 22 Hull Construction

Postby jimh » Mon Apr 18, 2022 11:06 pm

Vance's Revenge wrote:...I was thinking [the four circles in the aft well] were injection points for the foam, as well.
The foam is not injected. A liquid compound is poured into the space between the hull and liner. A chemical reaction very rapidly turns the liquid into an expanding foam. To insure venting of air, a number of sprue holes are placed in the liner mold to allow the expanding foam to push out any entrapped air. However, the sprue holes are usually at the bow or near the top of the gunwales. When the joining of the hulls is made, the boat is usually oriented with the bow higher than the stern, and a large sprue hole is located at the bow peak.

The circular sprue holes would typically be covered with a circular disk adhered in place, or in some instance just left with the foam faired to a smooth surface and sealed with some resin.

Vance's Revenge
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Re: 1987 REVENGE 22 Hull Construction

Postby Vance's Revenge » Mon Apr 18, 2022 11:59 pm

jimh wrote:
Vance's Revenge wrote:...I was thinking [the four circles in the aft well] were injection points for the foam, as well.
The foam is not injected. A liquid compound is poured into the space between the hull and liner. A chemical reaction very rapidly turns the liquid into an expanding foam. To insure venting of air, a number of sprue holes are placed in the liner mold to allow the expanding foam to push out any entrapped air. However, the sprue holes are usually at the bow or near the top of the gunwales. When the joining of the hulls is made, the boat is usually oriented with the bow higher than the stern, and a large sprue hole is located at the bow peak.

The circular sprue holes would typically be covered with a circular disk adhered in place, or in some instance just left with the foam faired to a smooth surface and sealed with some resin.


I have seen the video of the process and you are correct. I definitely used the wrong terminology.

I wonder if the holes are some sort of sprue hole(s) to ensure the foam density for the inboard motor mounting system?


Vance