CONTINUOUSWAVE

I just bought an [2009--please always use four digits to indicate a year] 150 Super Sport.



Above is the lower left mounting bolt I sent this photo to the dealer that sold me the boat. The dealer said I should pull off the mounting bolt, clean, and reseal. I don't believe [the brown liquid] is rust as there is body [viscosity] to the fluid.

I parked the boat in my garage. For the next three days this brownish fluid came out from under the bolt head, not from under the washer. After the boat was in the heated garage for three days, the flow stopped. I then pulled out [the boat or the bolt], cleaned [the boat or the bolt], and re-parked [the boat] in the garage. The fluid re-appeared for another day or two in lesser quantities.

Q1: [should 3M]4200 fast cure [be used] to reseal?

Q2: where can the fluid be coming from? The boat was not put in the water.

Q3: what is the brown pasty liquid?

Thanks.

It appears that cooler temperature allow it to be in the liquid form and heated areas cause it to stop. It may be uncured resin leaching out. While not a common problem, I have seen it reported occasionally over the years.

Park the boat outside, remove the bolt. Let it ooze a few days. Pull indoors, reinstall the bolt and apply sealant, (SikaFlex or Boat Life) not adhesive to the bolt hole and behind the washer and bolt head. Wipe away excess.

boatsmith wrote:...a photo (above) of the lower left mounting bolt...

Boats do not have a left or right side. They have Port or Starboard sides. I don't think the side of the boat where this fastener is located will be significant in re-sealing it or in determining the cause of the liquid oozing out.

boatsmith wrote:Q1: [should 3M]4200 fast cure [be used] to reseal?.

The 3M4200 product is a strong adhesive; a caulk or sealant is probably a better choice for this application where you do not require adhesion, just a seal. Sometime in the future you want to remove that fastener.

boatsmith wrote:Q2: where can the fluid be coming from? The boat was not put in the water.

The fluid is coming from inside the transom and hull.

boatsmith wrote:Q3: what is the brown pasty liquid?.

The brown viscous fluid is probably uncured polyester resin used in molding the hull or something brewed up in the interior of the hull over the past ten years from a chemical reaction of residual moisture, wood, uncured resin and other materials inside the hull, and from seawater that leaked in because the bolt, washer, and hole were not properly sealed.

boatsmith wrote:The dealer said I should pull the mounting bolt, clean and reseal.

Q4: Is this fastener normally submerged when the boat is in operation?

If so, then the fastener might not have been properly sealed at some time in the past, and some seawater got into the transom. There is no sign of any sealant on that fastener, and that is a concern.

Consider removing that fastener, letting the fluid ooze out until it seems to be done, then letting the area dry, perhaps aided by application of warm air blowing on the area for a day or two. Then inspect the hole, which I assume is an engine mounting bolt hole, and see if the transom wood is solid, dry, and free from rot. The next step will depend on what you find.

Q5: Was this boat previously used in saltwater or freshwater?

Phil T wrote:...[the brown fluid] may be uncured resin leaching out..I have seen it reported occasionally over the years.

Me too. I have seen it in person on a Boston Whaler boat hull--once--but not on my own boats.

Thanks for the responses.

The boat was used in saltwater.

The mounting location is just above the bottom paint so not submerged at rest. I would assume it is submerged running off plane.

Water leaked into the transom.

Saltwater is said to not induce wood rot. Freshwater makes wood rot. A use history for saltwater is a plus in this case.

jimh wrote:Saltwater is said to not induce wood rot. Freshwater makes wood rot. A use history for saltwater is a plus in this case.

Rot and soft, I have found the same over the years.
But wet and soft wood is not a lot different then rotten wood.

Salt water intrusion is still bad.

porthole wrote:

jimh wrote:Saltwater is said to not induce wood rot. Freshwater makes wood rot. A use history for saltwater is a plus in this case.

Rot and soft, I have found the same over the years.
But wet and soft wood is not a lot different then rotten wood.

Salt water intrusion is still bad.

Fully agree with salt or freshwater is not a good thing. Wood is said to not rot in saltwater, provided it's fully immersed in the absence of air, but over time it will soften and the laminated plywood will loose it's mechanical bond between each layer, not matter what glue is used.

I've seen plenty of boats with failed stingers or transoms that fail due to failure of the core in saltwater. Here was my other boat that I skinned the transom and removed most of the core with my hands and a couple simple tools. It was a total core failure from saltwater intrusion from the previous owner. I re-cored with a composite transom.





When I was younger, I knew a few old timers with wooden cabin cruisers and even in the salt water, they would put bags of rock salt in their bilge so it would be a heavy brine once mixing with the saltwater in the bilge.

This is not intended to scare the original poster, but to show that salt water can cause transom core failure. Personally, I think the original poster can remove the mounting bolts and dry the transom and then reseal with 4200 or another good quality material. It is important to use enough on the bolt and also where the bolt interface is with the inner and outer transom skins.

D-