The Perfect Storm

[Knot In Court]

I have a Ranger 27 that I purchased new in October of 2013. It has the Volvo Penta D-3 200i engine. The boat is located in SW Florida and kept on a covered lift on a canal behind the house. I previously had a 35’ Island Packet Cat that was kept at the dock in the water. The bottom had to be scraped by a diver every three weeks and I had to redo the bottom every 18 months. After 8 years of that, I bought the 27 hoping to avoid bottom paint and other maintenance issues. My wife and I do not take trips on the boat for more than 2 weeks at a time and I thought it would be doable to not put on bottom paint. We typically take 2-2 week trips in SW Florida with our boat club each year, one in the end of October and start of November, and the other the end of March and start of April. We had taken took two such trips since getting the boat and the bottom ended up with a few, small, white barnacles that were easily removed. When we take our trips the outside temperature is usually low 80s during the day and mid 60s at night with the water temperature around 70. We also towed the boat up to Minneapolis and went down the Mississippi River 250 miles and back for 2 weeks and had nothing on the bottom except some discoloration.
This October/November of 2015 we took our 2 week trip, which is the reason for this post. The outside air temperature was 90 to 92 every day and about 78 every night. After the trip I found out the water temperature was steady at 86 during our entire trip. New high temperature records were set during the two week trip that broke all records dating back to 1892!!! I started out the trip with 60 gallons of fuel and full water. We were basically traveling 125 miles north from Port Charlotte to Tarpon Springs and back. After 8 days we had traveled about 80 miles and used 30 gallons of fuel. The boat ran fine but on the 8th day I started to notice that my engine temp was approaching 200 to 203 degrees once I hit 3200 RPM. I topped off with fuel and water on the 9th day. We were traveling 25 miles and needed to travel at our faster speed, 3200+, in order to arrive at our destination in time to find a sports bar to watch the Vikings football game. I found that if I went over 3250, the temp would go right up to 205 to 207 at which time I immediately backed down to 3200. At 3200 it stayed right at 203, at 10.5 knots and 1.4 nmpg. It was a Sunday so I did not call anyone to address the problem. At 1700 rpm the boat ran at 174 as always. The temperature problem did not occur until I started to push it above 3000.
On Monday I started making calls as I wanted to be sure that I did not harm the engine by overheating it. I figured it was some sort of an engine problem and called Andrew at Ranger, my dealer in Florida and a number of mechanics. I was particularly interested at what temperature the engine could run without doing any damage. I did not get any good answers from Andrew or the dealer other than if the high temp alarm did not go off it was probably OK!! My mechanic said there were usually 3 things that caused the high temperature problem: first was a dirty bottom, second was too much weight and third was a possible raw water impeller failure or some other blockage in the cooling system. I assured him that the bottom was smooth as a baby’s butt, as I did not use bottom paint. I felt the engine was OK as it ran perfectly and the temp was normal at lower rpms. I immediately thought it must be the weight of full fuel and water because I added over 700 pounds of weight just before I started experiencing the problem. He suggested that I adjust the rpm to keep the temperature below 200 as the D-3 was meant to run about 195 at 3400 to 3600 rpm after which it would creep up over 200.
We had been anchoring out for 10 nights straight and I was going to have a mutiny unless I spent a few nights in a Marina!!! 90 degree temps and 95% humidity was getting to the Admiral!!! We decided to stay at the Dunedin, Florida City Marina and were given a slip next to the only Ranger Tug in the Marina, a 2014 29’, owned by Bob Barton. We spent two nights there, had a great time and learned a lot from Bob. We started discussing my overheating problem and he had story better than mine. His 29 had the Volvo D-4 260 hp engine. When he got the boat it had the same engine thru-hull and strainer as my 27. The thru-hull in the 27 has a 1” ID as does the input and output in the strainer. He had all sorts of overheating problems and his mechanic found out that his D-4 needs a 1 ½” ID thru-hull and strainer or his warranty would be voided. He contacted Ranger and they immediately sent him a new through hull and strainer and I believe paid for it to be installed. He has not had a problem since. Hopefully all 29s with D-4s now have the larger thru-hull and strainer. I surmise that it is not a problem when the water temperature is below 60 as it is in Seattle compared to above 80 in Florida. None the less, if you have a D-4 be sure you have the larger thru-hull and strainer. After learning this, I thought that I probably had the wrong thru-hull and strainer in my boat, which after much research, I do not think is the case.
Bob put me in touch with his mechanic who referred me to Suncoast Diesel Marine. They were very helpful and knowledgeable. The D-3 operating heat range is basically 174 to 195 degrees from 700 RPM to 3600 RPM with a gradual increase over 200 as 4100 RPM is approached. The D-4 is designed to run at 185 degrees no matter what the RPM. The thermostat on the D-3 does not fully open until 203 degrees and the high temp alarm goes off at 208 degrees. They could not diagnose the problem without looking at the boat and suggested I head home at a speed and RPM that would keep the temperature below 200 and document everything. After getting the boat back to my dock I could schedule an appointment if necessary.
We travelled 75 miles the first day and 50 miles the second day on our trip back from Tarpon Springs. I determined that my best RPM was 2910, which kept the temperature at 199 and below. The speed was 8 to 9.3 knots depending on the current with a fuel burn of 1.4 nmpg. By the second day I had used up 80 gallons of fuel and only carried 20 gallons of water and still had the same overheating problem. That ruled out the "too much weight scenario". By then I thought it must be some sort of blockage or other problem in the cooling system. I arrived home, put the boat on the lift and it looked like the bottom had brown indoor-outdoor carpet on it!!!! I could not believe it!! Sometimes the most logical answer to a problem is overlooked due to preconceived ideas. It certainly would have been easy to jump over the side and check the bottom but I honestly never thought it could have been the problem. The good news is the engine is fine, the bad news is I have decided to bite the bullet and put bottom paint on the boat.
Sorry about the length of this post but hopefully the information, assuming it is correct, is helpful. It certainly was not readily available and I had to talk to numerous individuals to compile it. It is my guess that I am one of the few individuals that tried to get by without bottom paint. It worked for 2 years but the “Perfect Storm” caught up with me. Our boat will be out of the water and on our lift or the trailer a minimum of 9 months a year. The boat will be used primarily in saltwater but also in fresh water at least a few times a year. I would appreciate any feedback and recommendation as to the best bottom paint to use and any tips that would be helpful in applying it.
Thanks in advance.

 

[knotflying]

A few questions, because your discovery does not seem to ring correctly with me. Assuming you had a lot of build up on the bottom of the boat, were you able to make full RPM's? I have had a good amount of build up of growth on my boat, even with bottom paint and had reduced speed, but never high temperatures. Is it possible that some of that build up has restricted flow to the heat exchanger? Before I would conclude that the build up is the issue I would clean the bottom and then go for a ride and see what happens.
Just a thought.

 

[Knot In Court]

Thanks Knotflying for your reply. You are absolutely right that I do not know for sure that the dirty bottom is the entire problem. Given what happened I still need to clean the bottom and add bottom paint to keep the build up from happening in the future. Once I do that I will run the boat and know if my issue goes beyond the dirty bottom. I never tried to increase the RPM to 4100 after I started having the problem but did get it up to 3600 with no problem other than the overheating. At the end of the day I usually increase my RPM to 4100 for a few minutes to clean out the engine after traveling at 1500 to 1700 all day. The second day of the trip we traveled from Palm Island to Sarasota at 3400 to 3600 RPM for 40 miles and had no sign of overheating as the bottom was still clean. The 5th day we traveled slow for a three hours and did bring it up to 4100 at the end of the day and again did not see a problem. I can only surmise that by the 8th or 9th day we were getting a considerable build up of barnacles, which coupled with full fuel and water, started causing the overheating problem. Even though the weight decreased as fuel was used the barnacles continued to get worse as we were gone for 14 days. I have experienced overheating on the Island Packet when the bottom and the props were not cleaned properly and even though I could get it up to max RPM it would overheat almost immediately. I am hoping it is just the dirty bottom as the engine only has 240 hours on it and the water flow appears to be fine. The issue I am struggling with is what type of bottom paint will be best for a boat that is not kept in the water all of the time. Thanks

 

[CAPTCRUNCH]

Check that thru-hull. I believe its diameter is barely adequate for the D-3 under the best of circumstances and inadequate at high rpm's in water 30 degrees warmer than Puget Sound with the strainer ("scoop") fouled. I'll post a photo example once I figure out how to do so. One of the things I miss most from my auxilliary sloop days is being able to look over the stern to see how much cooling water is coming out the exhaust as well as being able to reach down to feel how warm it is. Maybe a raw water flow sensor should be standard equipment.

Pettit Hydrocoat SR claims to be OK left dry for long periods, which I am in the process of testing.

 

[knotflying]

I use Petit Vivid. It is recommended for boats being towed and in and out of the water. I use my boat down here in Florida and up north in Rhode Island. I am usually good for 3 years before I need a new application.
Getting back to the overheating, hopefully it is as simple as a clean bottom. I assume you checked your water pump belt and your strainer? How many hours on the impeller?

 

[Irish Mist]

Wondering if the growth has restricted the water entering the strainer.

 

[CAPTCRUNCH]

These are the thru-hulls for the generator and a/c on my R-27 after about three summer months in Chesapeake Bay following a "complete" bottom job. The engine thru-hull was worse, but the photo didn't do it justice. IMO this fouling is the prime suspect in any case of high-rpm engine overheating.
https://drive.google.com/file/d/0B-QkPiGlxB0ganBxSEY5V1B0Mmc/view?usp=sharing

 

[Scuffy]

Our previous boat a 23' C-Dory had no bottom paint. I would tow it down to Florida for the month of March or February. Stayed in a slip in Key West, Marathon and Key Largo for a little over a week each place totaling all told to a month of time in the water. The last two years I spent the whole month of February in Marathon all without bottom paint. I always regularly waxed the bottom with Turtle wax paste wax. Before leaving for Florida I would put on a fresh coat and never got much of a build up. Maybe just started to see barnacles the size of a pencil dot left over after a power wash. They would come off with a scrape of a finger nail. The water temps however were in the low seventies. Our new boat Wefings of Eastpoint Florida in April 2015 bottom painted our boat with Mar Pro Super B Gold a brownish black color so far so good. I won't miss waxing the bottom of the boat anymore getting too old for that. The hose that runs from our strainer to the raw water pump 1 and 1/4" on our boat :mrgreen:

 

[JamesTXSD]

We used Micron Extra or CSC on our boat - very pleased with the effectiveness. Similar warm water temperatures along the Gulf Coast in south Texas, frequent trailer trips to other waters (fresh water, Pacific Northwest), no problems. Your best bet is to check with a couple boatyards in the area you will be most often to see what they recommend. Be sure to tell them your boat spends time on a trailer - some bottom paints lose their effectiveness when hauled for any length of time.

 

[Namaste]

We use Interlux Micron Extra on our R25 that is on the Peace River in Punta Gorda, FL. It spends summers on the trailer and five months on the water, brackish to salt. We power wash when haul and usually get two seasons out of 2 coats on hull and 3 near waterline.

In summer we live in Gloucester,Massachusetts where we never want to see another "perfect storm" again.

 

[doke01]

We live in New Jersey and use Aquagard water based bottom paint. You'd be amazed how much growth we get here during the summer months. Don't let the price fool you. We keep the boat in the water all summer and this stuff works better than the more expensive brands (believe me I've tested them). It's water based too so it is easy to clean up.

 

[Knot In Court]

I want to thank everyone for all the comments and information that I have received. I have decided to go with Pettit Vivid for bottom paint. I was inclined to go with Pettit Hydrocoat but The Pettit techs told me in my circumstance that Vivid would work better. Having a boat in Southwest Florida is a challenge given the high water temperatures 8 or 9 months a year and the constant sun. I was told that Vivid holds up much better when exposed to sun than Hydrocoat or other strictly ablative paints, due to special formulating. The boat is on a covered lift but the sun is still brutal. Otherwise Hydrocoat and Vivid would both work, along with a number of other brands.
I am still concerned with the water flow that I am getting to the engine. If you have a 27' you will notice that the thru-hull strainer on the engine intake is substantially smaller than the intake strainer for the Air Conditioner. Not only is it smaller but the opening between intake fins are also thinner and let in less water than the A/C intake. During my "Perfect Storm" trip I mentioned this to Andrew, as I thought someone may have put the wrong strainer on the wrong side. Andrew said that was not possible as the intake pipe for the A/C is 3/4" and the Engine is 1". That sounded good at the time but still did not make sense to me. I contacted Andrew after my return from the trip and he said he would look into the sizes of the intakes. He was right that the strainers were put on the proper sides and sent me pictures of them. I was very surprised to see that the thru-hull pipe and the strainer were attached and integral in his pictures so they could not have been put on wrong.
I mentioned previously that I had a 35' Island Packet Cat, which needed to have new bottom paint every 18 months. I believe I redid the bottom 4 or 5 times over the 8 years I owned the boat. The boat had 6 thru-hulls, 4 of which had strainer covers/pickups. These were separate from the actual thru-hull pipes and could be removed during repainting. After removing them I cleaned all the bottom paint and barnacles, inside and out, from them and did the same to the thru-hull pipes. If you looked at Captcrunch pictures he is correct that they did not even do justice as to the barnacle buildup. What you cannot see in his pictures are the barnacles that form in the pipe itself that need to be cleaned out. After cleaning up the strainers and pipes I put a coat of metal primer on them, a coat of tie-coat and 2 coats of bottom paint. This process did a good job of helping control the barnacles for 18 months and my diver really appreciated it. The reason I mention this is that it would be impossible to properly clean and paint the strainers and thru-hulls on the 27' without completely pulling them off the boat. It is probably OK in very cold water but not in Florida or other high build up areas of the country. I will not have the problem as there were no barnacles in the thru-hull strainer after my 2 week trip in 86 degree water. I am sure it would look like Captcrunch's if the boat was in the water all the time. I am presently working with Volvo to see if I need to change and enlarge my thru-hull configuration given my boating location. I will let everyone know what I learn particularly after the bottom is done and see if that was the cause of my overheating problem.