Mad River Explorer 16 Cracked Hull

Hello, this is my first post here so please excuse me if this question has already been asked.
I’m looking at purchasing a used Mad River Explorer 16 Royalex, but there is a vertical crack in the hull. Can this be repaired? If so, how?

Second pic of hull crack.

Hard to figure how they happened. Blunt force trauma.
Repairing Royalex is tricky. I would be tempted to just fill the crack with marine epoxy thickened with microballoons from both sides.

I’m not an expert just an interested observer.

It looks like the crack propagated from the screw between the two halves of the gunwale. Most likely then the blunt force trauma acted on it.

If the price is good because of the damage I would buy it and do a repair.

I would be tempted to drill a hole slightly past the end of the crack as a method of stress relief that the crack wont grow more. Then I would do as suggested above only with adding a thin patch over the area on the inside and then filling both the crack and hole from the outside with an epoxy. Maybe a little touch up paint on the outside as well.

The pros can tell me if I’m wrong.

If I owned that canoe, I would try the methods mentioned.
If I were looking to buy, I would run.
There are great deals on used canoes out there that don’t need repairs that may or may not work well.

That’s right we don’t know the overall condition, price or if there are lots of similar canoes as good deals in the area. I just paid 150 bucks for a OT Guide 147 poly canoe that was in nice shape and 10 years old. I thought that was a great deal and I see nice 16’ canoes going for around 500 and cheap 16s for 300.

It also depends on the usage the new owner will be putting it thru. If it is going to go on a lake or slow moving creek floats and I needed something for not a lot of money and didn’t care about the looks, I might just put a .06” aluminum plate on both sides glue it and clamp it and then drill and rivet it. That is if the price was right.

I see a few deep dents also so depending on the rest of the hull tell them you would give them 50 bucks and maybe you spend another 30 fixing it up and have a fun boat. I wouldn’t want to use it like it is but I’m sure you could.

It’s a cold crack, and not really a big deal, and certainly not a deal breaker. Cold cracks occur on royalex boats with wooden gunwales. The royalex contracts at a different rate than the wooden gunwales, stress builds up, and the result is a crack that originates where a screw penetrates the hull to fasten the gunwales. It rarely happens on boats with vinyl gunwales because the vinyl contracts at roughly the same rate as the royalex. Mad River even has a page about them on their website. They talk about how rare they are, but in reality they are actually quite common in cold areas.

Do NOT rivet a plate over it. The best fix is easily done with g-flex and some glass if you want (but probably not necessary). Google “royalex cold crack repair” and you’ll find lots of pages on it. This is a good discussion of Fixing Cold Cracks - Forums.

When done correctly, the repair is essentially as strong as the rest of the boat. I’ve paddled Class V in a royalex Ocoee with multiple cold crack repairs, and have 30+ year old Explorer with multiple cracks that I paddle often. These can be prevented by backing out the gunwale screws before storing the boat for winter, assuming you are in a cold climate. I spent some winters in the tropics and forgot to back out the gunwale screws before I left, so my cracks are my own fault (we routinely see temps well below zero).

Buy the boat (it’s still worth many hundreds of dollars). Fix the crack easily, and never look back. The older royalex Explorers are some of the best all-around hulls ever created, and that little cold crack is nothing to worry about.


Lots of info on how to repair cold cracks out there and some things that can be done to try and prevent them in the future.

Some boats don’t get them, some get many.

I would wager if you looked at every screw, you would find more than one crack.

Great info. Sounds like if they had slotted the holes in the hull they would have been fine. Not sure what their build process is but my guess is they drill thru all three at assembly and then run the screw. Maybe the inner gunwale is a clearance hole with a countersink along with the hull and then a pilot hole in the outer.

I see one poster advised drilling a hole to stop the crack from growing also.

Before making repairs, definitely drill at the bottom of the crack to keep it from growing. Just a small hole is necessary.

Drilling the hull holes a bit oversize seems to help. If memory serves, 1/8" is about right. Some folks loosen screws before winter storage… I have never done that.

I am convinced some of the Rx was substandard. I have, and have seen, many Rx/wood canoes with zero problems, and others that crack every year. I have also seen many with Al gunnels (rivets) that have cold cracks.

Either way, in Mad Rivers case given they were in VT, it’s a major major “whoopsie”.

I have heard a lot about cold cracks but have never seen one.
Thanks for the ID.