Salt Water, Fresh Water, and Your Boat's Bottom

[Don1500]

I will be home porting in a fresh water (? I wouldn't drink it) port and transiting to the oceans on a regular basis. What I would like to know is what special problems would I encounter? What benifits (If any) is there to being in fresh vrs salt water?

[senormechanico]

We did that scenario for years.
Benefits are zincs last a long time.
No barnacles, less slime.
Disadvantages were long transit to salt water, and spiders on deck.

[Bash]

I take my boat into fresh water--The Sacramento Delta--once a year and it loves it. I always make it a point to set my depthfinder offset in fresh water because the boat is lower on its waterline at that point.

Spiders. Yes. We always come back from the Delta with spiders. I love it when they start spinning webs on my wind turbine.

[rtbates]

no barnacles I'd imagine

[Don1500]

Originally Posted by rtbates

no barnacles I'd imagine

I had figured no barnicles, just wondered if alge and grasses grew better in fresh water. And if a barnicle or other salt water hazard does attach while in salt water, will it "jump ship" when you go to fresh water? (I think not)

[RTB]

Fresh water, as on an inland lake -

You still get plenty of slime growing, especially in the warmer months. I used to own a marina on a Texas lake. My pwer boat had a 140hp outboard and would run about 45mph when the bottom was clean and about 38mph if left unattended.

One thing I did notice was once on the trailer and the bottom scrubbed down, there was a thick layer of mineral deposit like you get inside a teapot or coffee maker. I didn't have bottom paint, just shiny gelcoat. Muratic acid was the best way to remove it. Not sure if it would be the same in salt water?

We are on Clear Lake with our current boat. Brackish water here. I just had the bottom (hard paint) scraped and cleaned by a diver. It had not been done for two years. He (the diver) said that in Florida, my bottom would look that bad after two weeks! I'm not sure if it is because of the marine life there or what, but obviously where the boat is has a big impact on marine growth.

[smurphny]

Disadvantages were long transit to salt water, and spiders on deck.

Yes, what is it with the darned spiders? Last year, kept the boat on a mooring for a while on Lake Champlain before heading south. Spiders absolutely infested the boat. Took me weeks to get rid of them once I got out of fresh water. Yech! Any entomologists out there? Why do they home in on boats and what can they possibly find to eat out on the water? Some of them are big, unhappy fellows.

[Don1500]

Originally Posted by smurphny

Yes, what is it with the darned spiders? Last year, kept the boat on a mooring for a while on Lake Champlain before heading south. Spiders absolutely infested the boat. Took me weeks to get rid of them once I got out of fresh water. Yech! Any entomologists out there? Why do they home in on boats and what can they possibly find to eat out on the water? Some of them are big, unhappy fellows.

Actually, the baby spiders "Fly" there. They let loose with a strand of silk and the wind takes them. I don't know why it doesnt happen on salt water, maybe spiders don't nest close to salt water. An entomologists I'm not, I know just enough to get in trouble.

[fstbttms]

Originally Posted by senormechanico

Benefits are zincs last a long time.

This is no benefit. This is an indication that your zinc anodes do not work in freshwater. Zinc is for saltwater only. Aluminum anodes should be used in freshwater.

[Beersmith]

I've read in a few articles that warm, fresh water is the idea condition for blistering in GRP hulls.

My boat was left in fresh water for about 9 years completely neglected. It is a perfect example of this idea. It was in salt water for about a month before I hauled it, but barely had anything but some slime on the bottom. I was shocked how clear the bottom was.

However, it spent that much time in warm, fresh water in FL without a haul-out for a long time. The paint eventually blistered, harboring water/chemicals next to the gelcoat; which eventually blistered itself, until laminate voids were developed and huge blisters were the result.

See these posts for my write ups about my blisters:

Project: Bottom Job | The Quest for Wind and Waves

Project – Bottom Job – At a stopping point | The Quest for Wind and Waves

[sarafina]

Transitioning from salt to fresh and back will keep your hull slick and clean... what grows in salt dies in fresh and visaversa! We used to do that trick in the delta.