CONTINUOUSWAVE

I recently purchased a 1985 SUPER SPORT 15 boat as a project. The hull bottom, transom, and floor are very solid, and there are no soft spots or delaminations.

The 1985 hull does have a number of problems, starting with the transom engine splash well drain tubes have corroded and cracked. Second, the embedded plywood in the transom and the foam are damp. Third, when I drilled a 0.25-inch diameter hole at the lowest point in the hull bottom no water drained out, but when I placed cotton in the new hole, it came out damp after a few seconds.


The hull sides on Port above the water line at the stern have multiple blisters, and the hull sides are soft in an area near the Boston Whaler harpoon logo. The hull also has several small gouges in the gel coat layer which exposed the laminate below.



Q1: should more test holes be drilled in the transom?

Q2: should more test holes be drilled into the hull bottom?



I do not know the amount of water that is contained in the hull. I am curious if a major deconstruction will be necessary. My intention is to get this 1985 SUPER SPORT 15 in good working order. Advice will be greatly appreciated.

ASIDE: Hello All. I'm new to Continuous wave and glad to be here.

--Mike

Your questions and concern for possible water in the Unibond hull of a Boston Whaler boat are answered in the Frequently Asked Questions answers. Please read at

Q3: Is there water in a Unibond hull?
https://continuouswave.com/whaler/reference/FAQ/#Q3

Advice for replacement of brass through-hull drains is also given in the FAQ. Read at

Q12: How Are brass drain tubes replaced?
https://continuouswave.com/whaler/reference/FAQ/#Q12

Advice for repairs to the Unibond hull are also mentioned in the FAQ. Read at

Q5: how is damage to a Unibond hull repaired?
https://continuouswave.com/whaler/reference/FAQ/#Q5

The continuousWave website had been providing a forum that concentrates on Boston Whaler boats since 2000, so in the past 24 years there have been many frequently-asked questions, and the FAQ provides concise answers to 15 of those questions. The FAQ makes for good background reading for anyone new to Boston Whaler boats.

The boat seen in Figure 3 does not quite exactly look like a SUPER SPORT 15. It looks like a SPORT 15 with a high seat back added to the bench seat. A SUPER SPORT 15 should have a seat back that is formed by a storage locker.

Also, the console height seen on your boat looks a bit taller than the normal console in a SUPER SPORT 15.

In the REFERENCE section of the website there is an article about the 15-foot hull. You can see the normal configuration of a SUPER SPORT 15 in that article.

https://continuouswave.com/whaler/refer ... superSport

Jimh, Thans for the information.

My 1985 SUPER SPORT 15 looks like the console was raised seven inches; see Figure 4 below.



The storage cabinet looks to have been removed as well. There are mounting holes on the back of the seat that seem appropriate for where the storage cabinet would be.



There may have been a fuel tank installed under the helm seat. There are three sets of mounting holes [in the deck] where the [some sort of hold-down fittings for an on-deck fuel tank] may have been located.

I opened the blisters on the hull side on Port; a small amount of moisture came out.



The section of repair information was very helpful. I'm still not sure if opening up a larger section is needed to find out how much water is within.

hallmj5 wrote: The section of repair information was very helpful.

Perhaps you are referring to this useful article:

The Cause of Hull Blisters
https://continuouswave.com/whaler/refer ... isters.pdf

While osmotic blisters were quite a problem for many fiberglass boats in the 1980's, I do not think hull blisters were particularly common on Boston Whaler boats.

The raising of the side console on the SUPER SPORT 15 is quite interesting. Many people have raised the center console on their OUTRAGE or MONTAUK boats, but I do not recall hearing of anyone raising the console on the SUPER SPORT 15. The work looks well done in Figure 4 as the joint line is barely visible.

UPDATE on REPAIRS

I found time to get into the [renovation of the 1985 SUPER SPORT 15 boat], and I found a large project ahead:

WET TRANSOM and HULL

The transom was removed, and the plywood was found completely saturated.


I cut a small test hole on the interior and also found the foam to be completely saturated. I decided to remove the floor, working towards the bow.




The amount of saturated foam was unbelievable. The entire hull from back to front was found soaking wet.



In addition, the port side foam [where there were hull blisters] was also saturated almost up to the gunwale.

At that point I had removed almost all the foam in the hull except for the saturated portside area above the water line. I'm still contemplating how to remove it. The amount of weight from all the wet foam is astonishing. The culprit turned out to be the area with the exterior blisters. It looks like it was damaged in the past and was poorly repaired; more than likely, this is the source for the insane amount of water in the foam.

I'm beginning to plan for re-foaming and installing a new floor with Coosa board.

I'd love to hear recommendations, experiences, and preferences, and particularly, the best method for re-foaming, and whether to re-foam before or after the deck floor is installed.

Thank you,
Mike

[Figure 10] shows the area of the poor patch. [Moderator's note--please explain further this comment is not clearly stated.]

My first reaction to this new update is to be quite astonished at the extent of ingress of water you have found in the interior of the Unibond hull. The source of the water must have been below the waterline and subject to significant water pressure resulting from the hull running at speed through the water to force that much water into the hull.

Second comment: Figures 10 and 11 are very interesting because they show an element of the construction of a Unibond hull that is seldom seen: the shear braces.

The shear braces are structural elements that connect the hull molded part with the hull liner molded part when the two parts are joined together in clamped molds and the space between them is filled with foam. In Figure 10 you can see the remains of a shear brace that has some of the plywood reinforcement still attached to in; in Figure 11 you can see what appears to be a shear brace in the middle of the hull that has been left in place.

For more about shear braces see this article:

Original Patent of the Boston Whaler Hull Construction
https://continuouswave.com/whaler/refer ... atent.html

hallmj5 wrote:I'd love to hear recommendations, experiences, and preferences, and particularly, the best method for re-foaming, and whether to re-foam before or after the deck floor is installed.

If you try to introduce new foam after the cockpit deck has been restored, I doubt it would be successful. In the original process of creating a Unibond hull the two parts, hull and liner, are still in their molds, and the molds are made to be clamped together. The expansion of the foam is limited by closing off the sprue hole. This limits the expansion and produces a higher density foam than would occur if the foam were allowed to expand against open air. Also, the pressure of the expanding foam might distort the shape of the liner or huill.

One way to recreate the higher density foam and to avoid any distortion of the hull or deck is to purchase already cured foam in blocks or sheets. Then individually cut and shape pieces of the higher density foam to fit the shapes in the hull as best as possible while the cut-away deck sections are not replaced. That will be tedious, for sure.

Use an adhesive (like thickened epoxy resin) to secure the new foam to the hull. When the epoxy resin has fully cured and the new foam is firmly fastened to the hull, then you could sculpt and fair the foam at the cockpit deck surfaces and cockpit inwales to be fair and level.

For the deck you could bond the new plywood to the foam with more epoxy resin. Then finally replace the laminated deck sections you cut off to gain access, again bonding them in place with thickened epoxy resin. For the cockpit inwales the cut-out laminated portions would be bonded to the new foam.

jimh--thank you for the detailed response!.

To clarify Figure 10, the yellow color in the photo is not foam, but a previous fiberglass patch (not by me), which appears to be there to repair damage. I bet this is where the extreme amount of water came in.





I didn't weigh the saturated foam, but I bet I removed over 300-lbs of wet foam.

You may be able to duplicate the construction of the shear braces by wrapping a carefully cut piece of pre-cast high-density foam with fiberglass cloth, and bonding it to the hull button with epoxy, and also using epoxy on the sides. Then leaving the exposed laminate on top waiting for a primary bond to the plywood under-deck reinforcement.

The shear braces are essential for connecting the hull molded part to the liner molded part in multiple places. Read the patent article (linked above) to find out more about shear braces. The shear braces are part of the Boston Whaler patented method of construction. But they were seldom--if ever-- mentioned in Boston Whaler literature. The shear brace feature kept as sort of trade secret.