Cutting Open Unibond Hulls To Assess Condition of Stringers and Foam

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
AndrewJaxFL
Posts: 5
Joined: Sun May 05, 2019 1:14 pm

Cutting Open Unibond Hulls To Assess Condition of Stringers and Foam

Postby AndrewJaxFL » Mon Apr 26, 2021 9:25 am

On a 1999 DAUNTLESS 14, where can an opening be cut into the deck to reveal the interior foam and stringers to allow their condition to be assessed?

BACKSTORY
I have removed the console, bench seat, live well, and fuel tank from my 1999 Dauntless 14 to prepare for a re-power.

Jefecinco
Posts: 1592
Joined: Fri Oct 09, 2015 6:35 pm
Location: Gulf Shores, AL

Re: Cutting Open Unibond Hulls To Assess Condition of Stringers and Foam

Postby Jefecinco » Mon Apr 26, 2021 9:49 am

Cutting open the hull to evaluate foam condition seems extreme. There are far less difficult means of checking the condition of the hull foam. I don't believe you will find any stringers in your Dauntless hull. I believe it is all foam.

If you Dauntless is not much overweight it is safe to conclude the foam is not saturated and the boat will be safe for operation. The main thing to determine is if the scuppers are above the water when the boat is afloat. Were the scuppers of you Dauntless above the water before you started your repower project? If so, leave the hull integrity intact.
Butch

AndrewJaxFL
Posts: 5
Joined: Sun May 05, 2019 1:14 pm

Re: Cutting Open Unibond Hulls To Assess Condition of Stringers and Foam

Postby AndrewJaxFL » Mon Apr 26, 2021 9:53 am

They were just below the waterline with a person in the boat, empty they sat just above.
Any info on the less difficult means to check, I appreciate the help!

User avatar
Phil T
Posts: 2602
Joined: Thu Oct 22, 2015 6:08 pm
Location: Was Maine. Temporarily Kentucky

Re: Cutting Open Unibond Hulls To Assess Condition of Stringers and Foam

Postby Phil T » Mon Apr 26, 2021 10:16 am

Andrew -

There are not stringers in any Boston Whalers.

The structural stregnth comes from a bonded sandwich of the outer and inner fiberglass layers with foam in the middle.

Cutting into the floor or the hull affects the integerity of the boat.

If you are concerned about the boat, get it weighed. This will tell you more than cutting it open.

Seal any holes and cracks.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
Posts: 11673
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Cutting Open Unibond Hulls To Assess Condition of Stringers and Foam

Postby jimh » Mon Apr 26, 2021 11:18 am

As already mentioned, when the boat sits in static trim the position of the engine splash well drains relative to the water line at the transom is a good indicator of the boat's weight and its engine weight. It is quite common for boats with heavy engines to sit at rest with the engine splash well drain submerged into the water. The engine weight likely has the most influence on the boat static trim.

What was the original engine and what was the engine weight when you observed that the engine splash well drains were underwater at rest?

jimh
Posts: 11673
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Cutting Open Unibond Hulls To Assess Condition of Stringers and Foam

Postby jimh » Mon Apr 26, 2021 11:21 am

Regarding what can be found inside the enclosed space of a Boston Whaler Unibond hull other than foam, see:

Original Patent of the Boston Whaler Hull Construction
http://continuouswave.com/whaler/reference/originalPatent.html

The patent discloses the use of interconnecting braces between the hull and liner molded parts that are called "shear braces."