Special requirements for saltwater vs freshwater use?

[Ken Wolkens]

I'm starting to look at freshwater boats and a broker on lake michigan told me that a freshwater boat would need to be converted/prepped for saltwater.

I would assume a 40-50' Sea Ray with diesels would be ready for saltwater from the factory.

Was he for real or just trying to drive the cost up?

 

[ASH]

Every fresh water boat I have been around was equipped with anodes (that never get replaced). I am not sure if there are "add ons" to give you more protection from corrosion.......If he is talking fresh water cooling on the engine block to a closed cooling system then yes!!!! You specifically mention diesels and 40+ which I would say are already closed cooling engine blocks and "salt water ready". I would not discount his opinions but have him make you an itemized list of needs.

 

[fwebster]

All Sea Rays in the 40+ ft. category are built to live and perform in saltwater. You don't need to do anything to move a freshwater boat to saltwater. However, the bottom paint will be dead and won't repel hard growth or slime in salt water. As a part of a bottom job you should replace the hull and tab anodes. As a part of bringing your maintenance current, you should also replace all engine anodes with zinc anodes.

 

[Ken Wolkens]

Frank,

You sir are a god-send. Thanks for the confirmation. I always look forward to your responses. Why is the bottom paint "dead"? Is it a time in the fresh water thing? A coupe of the boats have had recent bottom paint, maybe a season or two is why I ask.

Ash,

You also are dead on. I'm aware of the freshwater/closed cooling system differences but as you said on diesels they should be closed anyhow.

Thanks guys!

Ken

 

[shinsr]

I am looking at a fresh water 48da. The one thing I have identified is making sure the zincs are not magnesium - they are worthless in salt water. The other is fresh bottom paint, including the trim tabs (tabs on this boat were never even painted). Positives of fresh water are limited corrosion throughout the boat due to lack of salt exposure, and the running gear looks like new. My experience in watching the market is that most freshwater boats want a premium for that reason - people don't want to bring salt water boats into fresh water.

 

[sandydlc]

I am looking at a fresh water 48da. The one thing I have identified is making sure the zincs are not magnesium - they are worthless in salt water. The other is fresh bottom paint, including the trim tabs (tabs on this boat were never even painted). Positives of fresh water are limited corrosion throughout the boat due to lack of salt exposure, and the running gear looks like new. My experience in watching the market is that most freshwater boats want a premium for that reason - people don't want to bring salt water boats into fresh water.

I speak from experience when I say that galvanic corrosion can definitely strike while in freshwater and according to experts I've spoken to, it can actually be worse. I would recommend a galvanic isolator if the boat doesn't already have one. Anodes recommended for saltwater only are zinc. For a mix of fresh and occasional saltwater, go with aluminum and magnesium for freshwater only.

If you can't haul out for a season, it's well worth hiring a diver to replace your anodes. Cheap insurance compared to what could be thousands of dollars in replacing outdrives.

Here is a good explanation of how corrosion works: http://www.boatus.com/seaworthy/galvanic/

Invest in a good surveyor for both the vessel as well as a mechanical survey for the engines. It's well worth the cost and the documents are great to review later on.

 

[Capt. Rusty Higgins]

Am copying the two paints we used over the last 10 years with short description of both. Notice they are both ablative paints which are designed to dissolve over a period of time, thusly not allowing barnacles or hard growth to remain attached. Listen to FW when he says regardless of what you see (freshwater paint may still look good even though it has lost it's properties) repaint her. I will bet the boat you are researching has Pettit Paint but both are great products. DO NOT use any off brand paints as you will only have probs with adhering and longevity.
AND while out of the water doing this fairly easy repaint (3/8 nap roller will work just fine)...again listen to the professor as he highly suggest replacing all anodes to ensure they are zinc. I personally recommend you replace all fluids as well, such as oils and filters. It gives the piece of mind that you the new owner, now know exactly what the maintenance schedule is and not going off the word of a broker or previous owner.

2005- PAINT, BOTTOM BLACK HYDROCOAT-PETTIT PAINT
2015- PAINT, BOTTOM AQUA BLACK- INTERLUX

Pettit Hydrocoat is a water-cleanup ablative antifouling bottom paint
Interlux Aqua One is a water-based ablative antifouling paint

Want more...ask Frank, LOL

Capt. Rusty

 

[fwebster]

Frank,

You sir are a god-send. Thanks for the confirmation. I always look forward to your responses. Why is the bottom paint "dead"? Is it a time in the fresh water thing? A coupe of the boats have had recent bottom paint, maybe a season or two is why I ask.

Ash,

You also are dead on. I'm aware of the freshwater/closed cooling system differences but as you said on diesels they should be closed anyhow.

Thanks guys!

Ken

Ken,

The paint is dead because the metals (almost always copper now) which are the anti-fouling component in bottom paint is oxidized at the surface and in freshwater is almost always covered by a coating of algae. If the copper isn't exposed, then the paint is inert and will not prevent marine growth.

The other issue with old paint is that you never know for sure what it is or when it was applied. I live in the heart of the Corp of Engineer/TVA lake system in Tennessee part time and on the Gulf coast part time. In Tennessee, almost everyone uses a hard bottom paint because there is no hard marine growth like barnacles, worms, sea potatoes, oysters, etc. Since nothing but algae grows on the bottom in freshwater, the bottom paint is mostly cosmetic and most everyone only repaints when the boat gets where it looks bad......3-5 years. In salt water, we do get hard growth in a matter of days. Everyone with a planing hull uses an ablative bottom paint on the hull and a hard paint on the hardware. Ablative paints wear off as the boat passes thru the water thus exposing a fresh antifouiling surface. If you leave your boat for as long as a month without running it, you will normally need a diver to clean the hull every 30-45 days. Properly cared for and properly applied a bottom job in salt water using a good ablative paint will last 3 years.

You asked about the differences between salt and freshwater Sea Rays in the 40 ft category and this is probably the biggest one. But, for me, it is just a management thing. A boat is a sizeable investment and it needs to be managed that way. I haul my boat out every February to check the bottom, hardware, bottom paint condition, pressure wash her and wax the hull.......depending upon use during the year, I may need to repaint the hardware and we sand and repaint the hull every 3rd year. On a new to you boat, you can try changing anodes and running the boat on whatever bottom paint is on her, but my bet is that you will not be happy with the performance because you will get enough bottom growth to take 3-5 kts off the cruise and reduce your rpms by 3-400 at WOT.

 

[Ken Wolkens]

Thank you for all of the feedback. My main take-away is not to look at fresh or semi-fresh bottom paint if it was used in freshwater as a bonus and plan to paint the bottom as soon as it arrives here.

The diver for monthly bottom cleaning is already on the maintenance plan.

Thanks again, Ken

 

[JC3]

Ken, Have you already bought a boat? If not I would suggest you post any questions you might have or pop up during the buying process.
The amount of knowledge is only surpassed by the willingness to help potential buyers. Pay particular attention to Frank W comments.
Good luck with your purchase, JC

 

[sandydlc]

Don't forget appropriate sacrificial anodes!!

 

[shinsr]

Ken,

The paint is dead because the metals (almost always copper now) which are the anti-fouling component in bottom paint is oxidized at the surface and in freshwater is almost always covered by a coating of algae. If the copper isn't exposed, then the paint is inert and will not prevent marine growth.

The other issue with old paint is that you never know for sure what it is or when it was applied. I live in the heart of the Corp of Engineer/TVA lake system in Tennessee part time and on the Gulf coast part time. In Tennessee, almost everyone uses a hard bottom paint because there is no hard marine growth like barnacles, worms, sea potatoes, oysters, etc. Since nothing but algae grows on the bottom in freshwater, the bottom paint is mostly cosmetic and most everyone only repaints when the boat gets where it looks bad......3-5 years. In salt water, we do get hard growth in a matter of days. Everyone with a planing hull uses an ablative bottom paint on the hull and a hard paint on the hardware. Ablative paints wear off as the boat passes thru the water thus exposing a fresh antifouiling surface. If you leave your boat for as long as a month without running it, you will normally need a diver to clean the hull every 30-45 days. Properly cared for and properly applied a bottom job in salt water using a good ablative paint will last 3 years.

You asked about the differences between salt and freshwater Sea Rays in the 40 ft category and this is probably the biggest one. But, for me, it is just a management thing. A boat is a sizeable investment and it needs to be managed that way. I haul my boat out every February to check the bottom, hardware, bottom paint condition, pressure wash her and wax the hull.......depending upon use during the year, I may need to repaint the hardware and we sand and repaint the hull every 3rd year. On a new to you boat, you can try changing anodes and running the boat on whatever bottom paint is on her, but my bet is that you will not be happy with the performance because you will get enough bottom growth to take 3-5 kts off the cruise and reduce your rpms by 3-400 at WOT.

Frank - if I could ask a follow up to your post - I am buying a fresh water 48da, bottom is very clean but hasn't been painted in 3 years. If I have it painted where she sits now (sanding and 2 coats hydrocoat) and she sits in fresh water for 3 weeks or so before I can get her home into salt water, is that too much time where the ablative properties will be impacted? If I wait to paint her when I get to home port, it will cost me another boat buck in a long haul - she is on the hard now so if I paint before launch no extra costs - I am changing all zincs to zinc pre launch as wel. Thanks in advance, Russ.

 

[Clemson]

Frank - if I could ask a follow up to your post - I am buying a fresh water 48da, bottom is very clean but hasn't been painted in 3 years. If I have it painted where she sits now (sanding and 2 coats hydrocoat) and she sits in fresh water for 3 weeks or so before I can get her home into salt water, is that too much time where the ablative properties will be impacted? If I wait to paint her when I get to home port, it will cost me another boat buck in a long haul - she is on the hard now so if I paint before launch no extra costs - I am changing all zincs to zinc pre launch as wel. Thanks in advance, Russ.

Ken...There are plenty of experts out there and all kinds of stories regarding bottom paints. I have owned nine different boats over the years and all resided in salt water. I have never used an ablative paint in over 30 years. My last Sea Ray was a 480 Sundancer (2007). I use Two coats of Sea Hawk and Prop Speed on shafts, struts and props. The hull is "rubbed" monthly and the paint has lasted no less than 3.5 seasons. My current 48Sedan Bridge came from Chicago and never saw salt water.

A bigger issue is what called marine age with those diesels. People will tell you...don't worry..it's a fresh water boat...Bull... Make sure you know exactly what condition the heat exchangers and the entire raw water side of the engines are in. Has the raw water side been serviced? Consider installing a fresh water flush system on the mains and Genset. Would highly recommend you join the boatdiesel.com forum. A huge asset for owners that is moderated by marine professionals who want to,help. Good luck