CONTINUOUSWAVE

Q1: to remove crow's feet cracks (which are everywhere on the gelcoat surface of a 1980 MONTAUK 17) do I sand back all the gelcoat?

Q2: should I cut open the cockpit deck in order to see what damage lies below soft areas of the deck?

[Survey question removed. Please do not ask survey questions, such as "Has anybody ever...(done something)?"]


BACKSTORY
I have removed everything from my 1980 MONTAUK 17 boat, and I now have a bare to begin restoration The gel coat layer on my 1980 MONTAUK 17 has cracks everywhere. The deck has small cracks and soft or spongey areas located near the cooler front seat . These cracks are big enough to allow seawater into the hull below. I am now ready to start the restoration. I will need a lot of advice.

The best way so elicit advice is as you have already done: ask specific questions.

The Tunaman wrote:Q1: to remove crow's feet cracks (which are everywhere on the gelcoat surface of a 1980 MONTAUK 17) do I sand back all the gelcoat?

If there is cracking and crazing throughout the gel coat layer, the repair of each individual crack will be extraordinarily tedious and more or less impossible to accomplish. For hulls with gel coat in that condition the best approach is to widen the cracks, sand the surface, apply a fairing compound, sand the surface, more fairing compound, and final sanding, then carefully clean and prepare for painting over the entire area with a good boat paint.

That process is demonstrated by TotalBoat, a maker of various marine paints, fairing compounds, and epoxy resins, in a well-done, highly informative presentation on their YouTube Channel, which I strongly suggest you watch and review several times. I have no affiliation with TotalBoat, but I am happy to recommend you watch their presentation on Boston Whaler hull crazing and cracking repair at

Boston Whaler Crazing Repair
https://www.youtube.com/watch?v=4tZDBOYqdfA&t=3s

The Tunaman wrote:Q2: should I cut open the cockpit deck in order to see what damage lies below soft areas of the deck?

Cutting a large opening in the cockpit deck laminate layer is a big undertaking. To investigate a soft area, I would proceed less intrusively.

My method--which I have never tried--would be to drill a number of 0.25-inch-diameter holes in the area of the soft deck. Then attempt to remove any water that has accumulated in that area by applying suction using a powerful wet-dry vacuum. You could begin with individual holes, and see what sort of outcome you get with this method.

I would expect that after extracting water, more water might migrate to that area in a few days, so you may need to repeat the process. If you reach a point where you have managed to pull out all the water possible with this method, you could drill a few more holes in the gaps between the initial hole set, and see if that provides more water to remove.

If you ever get to some point where the underlying interior of the hull seems to be dry, then you could begin filling the holes by injecting a mix of epoxy resin and filler, such as micro-balloon filler or other non-absorbent material, into the individual holes.

If the holes are located in an areas that is very visible, leave some space in the hole to receive color-matching gel coat resin. Or, if you are going to repaint the whole area, just leave enough space that the fairing compound can fill.

In the worst possible situation, you may never be able to dry the soft area, and at that point you could consider cutting a rectangular section of the deck and trying to pry up that section. If there is a serious amount of wet wood and wet foam in the Unibond hull, then you could proceed to cut and remove all the wet wood and wet foam.

After removing the wet wood and foam, you would then buy some pre-cast high density foam blocks, and use them to fill the space where the foam was removed, gluing these blocks to the existing foam and to each other as you go. The plywood reinforcement is restored and put back in place, carefully set to be flat and parallel with the remaining deck but well below the surface .

Then with careful work, you could possible chisel off the old wood and foam from the underside of the deck section you cut out, replace the wet or rotted wood with new marine plywood that you seal the cut edges with epoxy resin, then adhere the deck laminate section to the wood. Then contour the foam blocks to the new deck and wood fit perfectly and make a flush fit to the original deck.

For more advice on hull repairs, read my reproduction of the Boston Whaler repair sheet distributed many years ago, and now available in the REFERENCE Section at

Boston Whaler Hull Patch Kit Instructions
https://continuouswave.com/whaler/refer ... tions.html

and particularly the instructions at

"5. Large Structural Repairs (rebuilding of crushed or ripped away sections)"

Thank you. [You provided] a lot of valuable information. I will look up those references. I'm sure I will have further questions.

To clarify the scope of the restoration:

• the crow's feet or crazing is all over the top deck of the boat, so any flat surfaces that face upwards toward the sun are gone;
• the floor is soft and very spongy in the middle of the deck when you walk on it. I definitely know there is water in there and so the wood and foam filling is all water soaked.

Q3: based this new information, what recommendations do you have now?

The Tunaman wrote:Q3: based this new information, what recommendations do you have now?

I do not have any new advice to offer. The advice I offered was already based on your initial description of the problem, which seems to be just as you further described the condition of the boat when you restated the scope of your project.

For example, in your initial post you described the crazing as follows:

The Tunaman wrote:Q1: to remove crow's feet cracks (which are everywhere on the gelcoat surface of a 1980 MONTAUK 17)...

Then in your more recent reply you described the crazing as follows:

The Tunaman wrote:...the crow's feet or crazing is all over the top deck of the boat...

I do not see any element of the crazing that is different in the second statement than in the first.

Regarding the soft deck area, in your initial post you described it as follows:

The Tunaman wrote:...soft areas of the deck.

Then in your more recent reply you described the soft areas of the deck as follows:

The Tunaman wrote:...the floor is soft and very spongy in the middle of the deck when you walk on it.

I do not see any element of the soft deck areas that is different in the second statement than in the first.

Please review my initial remarks on your situation, follow the resources that are hyperlinked, and study those methods. There is no magic bullet that will easily and effortlessly cure the two problems on your 1980 MONTAUK 17, which are gel coat crazing and soft deck areas.

You might find interesting the boat shown below in Figure 1, where you can see how a very considerable amount of wet foam was removed from the Unibond hull of a 16-footer.



Fig. 1. A older 16-foot hull in the process of being rebuilt. The original deck laminate has been cut out and all the wet foam removed.

To read more about this boat, visit CETACEA Page 30 and read under the sub-heading "pre-1972 Whaler 16 Restoration"

https://continuouswave.com/whaler/cetacea/cetaceaPage30.html