Join Date: Feb 2000
Location: Annapolis, Md
Thanked 181 Times in 147 Posts
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Hunter vs. Beneteau
On the newer Hunters the hull deck joint occurs below the deck level. The deck molding turns down toward the topsides and then has a flange that turns outward. Similarly the top of the hull molding has a flange that turns out. This joint is then glued together and bolted. The primary bond is formed by a very hogh strength adhesive developed for the aerospace industry. It is similar to the adhesive used by Catalina.
The out-turning flanges are then covered by a rubber rub rail. A rolled out flange is less expensive and a bit easier to build as the molds do not have to be disassembled to remove the flange and the radii are all outside turns.
In my mind it is preferable for the joint to occur at the deck line with a flange turned in. When the flange turns in at the underside of the deck the joint only experiences sheer, compression and tension but no bending. With an outward facing flange the flange can experience a lot of bending moment across the joint.
The other issue is that the flanges can be much larger on an inward facing flange. This means more surface for the adhesive (reducing loads per square inch) and there is more room for bolting.
Last year I moderated an online question and answer session with a rep from Hunter. In that discussion with Hunter, the joint question was addressed to Hunter. Hunter was asked, "Why does Hunter use an outward facing flange hull deck joint?"
Hunter responded, "We do use outboard lapped flanges because they are easier to construct than inboard flanges. We cycle tooling at a rather high rate and to obtain that rate sometimes we need two to four sets of identical tooling. That adds up fast because tooling is the major investment in FRP construction. Outward flange tooling allows more rapid reuse of tooling.
I don''t argue that an inboard lapped flange is better. But I will argue that an outboard flange for the reasons mentioned earlier is more than adequate and is construction friendly. It is certainly better than a shoe box joint that provides none of the benefits of either and is more prone to leaking and harder to repair if damaged. Inboard lapped joints tend to be harder to repair and harder to access it''s fasteners."
Its hard to describe this kind of thing over this media so I don''t know if that answers you question clearly but I would be glad to discuss it further.