SPORT 15 Hull and Transom Thickness

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Hamertime614
Posts: 1
Joined: Fri Sep 02, 2022 1:00 pm

SPORT 15 Hull and Transom Thickness

Postby Hamertime614 » Fri Sep 02, 2022 1:07 pm

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Q1: what is the hull thickness of a SPORT 15?

Q2: what is the transom thickness of a SPORT 15?

BACKSTORY. I have a [unspecified] Boston [Whaler boat] that [I believe is] full of water under the deck. This is a recurring problem. [Instead of drilling holes and getting water inside [the hull]. I [plan] to install a centerline drain directly above the top of the interior of the hull. To do that the thickness of the hull must be known accurately.

jimh
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Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: SPORT 15 Hull and Transom Thickness

Postby jimh » Fri Sep 02, 2022 1:33 pm

If you are asking about the thickness of the gel coat and laminate layers used in making a Unibond hull for a Boston Whaler, the thickness of the layup varies depending on the strength required for a specific hull and at a specific point.

The best method for you to obtain the thickness of the laminate at the point where you want to install a drain is to drill a small pilot hole where you want to install the drain. The passage of the drill from the laminate into the foam will signal to you a big reduction in drilling force as your are drilling, that is, drill will cut through the foam more easily than through the laminate layers. From that signal you will know the depth of the laminate by immediately stopping the drilling and making the depth on the drill bit with tape.

To demonstrate how the thickness of a Boston Whaler Unibond hull can vary, see Figure 1 below.

Image
Fig. 1. A section of an unknown year, model, and length Boston Whaler Unibond hull showing the upper laminate layer, the middle foam layer, and the lower laminate layer. Note that the thickness of the laminate layer can vary considerably depending on the particular hull and the particular area of the hull and the strength required or due to the presence of embedded reinforcements.

The above photograph appeared originally in a post I made in an older thread. See

Thickness of a Boston Whaler Hull
https://continuouswave.com/ubb/Forum1/HTML/010888.html

That thread may contain useful information for you.

Regarding the thickness of the laminate at the transom, see a prior discussion on that topic:

Green Line Transom Joint
https://continuouswave.com/forum/viewtopic.php?t=6209

The thread contains an image of the green line transom joint of a 1976 SPORT 15 boat, and thus may be useful for you.

Q3: how do you propose to drain water from beneath the deck with an opening in the upper surface of deck?

Water flow is according to gravity, so a drain that opens to the deck will never produce a flow of water out of the hull unless the hull is inverted.