CHB/ mt 34 cement problem/solution
It is my understanding that these most popular trawlers from the 70s through the 80s all have a concrete ballast layer between the outer hull and a thin fiberglass skin. Water inevitably gets in, if it ever, EVER, overwinters where it freezes , a bulge may appear in the thin layer.
In our 1988 Marine trader, I noticed the bulge, then crack, then 2years later the stink. I cut out the cracked glass layer to reveal 2” of brownish decomposed concrete. I used a wet vac to suck the mess out, that mess was most likely micro marine life, when this was removed the layer of concrete was rock solid.
I read the blog “saving Tortuga” with a mix of horror and admiration. I hope that I have discovered a better approach to “saving” Marine Trader 34’s. These boats earned a special place in trawler history, low cost, high on teak and space, and significantly lighter than a 36’ vessel, which is important for a couple cruising. “Trawler Beach House” provides a wonderful honest account of the integrity of these boats.
While sucking the water and muck out of the bilge I realized that the vac was pulling water through the concrete, I made a sump the size of a coffee can about 3” lower than the concrete base (4lb hand held sledge and chisel ) into which a bilge pump fits perfectly.
Like many owners the material cost of upgrading vastly exceeds the resale value. For me the boat, because of its design integrity and fundamental good workmanship is worth bringing it up to contemporary (ABYC) standards.
To some degree, knowing the flaws, leaves you more prepared for the reality. All my own humble opinion.