Wet storage compartment, deck drains, Ventilation

The wet compartment floor and soft wood is a common issue with the Ranger and Cutwater cockpit drains. This design has flaws. IF the boat were to sit perfectly level fwd and aft, port and starboard. IF the deck drains were installed with a gradual fall no low spots. IF the drain hoses are completely clean with no obstructions. IF the Screens at the deck drains are removed or cleaned. IF the deck hatches have good seals installed and are sealing properly. IF the deck latches were properly installed with sealant and the o-rings in the latches are in good condition. The design has a chance of working as a self bailing cockpit and the compartments will stay dry.

I have a full enclosure and in a heavy rain I have seen water over flow into my starboard compartment. I have tried to cover all the (IF'S) stated above but the water makes its way in at the corner of the trough opposite the the drain. I am proactive at making sure I dry the compartment when water leaks into it. I am also proactive at maintaining the limber holes that drains water from these side compartments to the center bilge.

The wood used in these compartments seems to be a good quality plywood (I assume marine grade but I don't know) The top side of the wood is sealed with Gelcoat. The bottom side is not sealed. The ventilation in these compartments is limited, other than the gaps between the hull and the cockpit liner. The gaps that allow air in and out can be obstructed by wire looms, hose runs, and equipment being stored in the compartments. If water and moisture gets into theses compartments and it is not dried out the wood will rot in a short period of time. Poor drainage and no ventilation in a boat with wood components is a combination for rot and mold.

It's a boat! You can't do anything about water and moisture! You can't do anything about the unsealed wood in the bilge unless you remove it. You can maintain all the "IF'S" . Maintain the limber holes by confirming they are not plugged. Make sure there is good air flow in and out of the compartments. You have a fighting chance of the compartments staying dry and reducing the chance of rot.

Maintaining the boat to float level is a good thing to do but all I can say to that is GOOD LUCK! An 8'6" beam boat is very sensitive to weight. Even a 10' beam boat is. Sliding a cooler from one side of the boat to the other can throw it off.

"Ventilation" I have beat this dead horse on TugNuts for a long time. Sorry for my passion on the subject. A boat built without a ventilation system can work. That is proven Ranger Tugs and Cutwaters operate with out a ventilation system installed. Marine ventilation is a necessity for the performance of engines and other equipment. Ventilation systems both move the air and equalize humidity levels inside and outside the boat. I would assume when the design engineers at Fluid Motion decided that the air gaps around the cockpit would be adequate. The calculations proved enough air flow to operate the engines, generators, battery ventilation and equalize the humidity levels inside and outside the boat.( I assume) The engineers concluded "we don't need to put ventilation is our boats. ABYC states diesel powered boats can operate safely without ventilation. The air requirements to run the engines is met." They must have been right because they have built a lot of boats and no one has had an issue ???

Did the design engineers figure in the wire loom runs and hose runs that are installed between the liner and the hull ? Does this disrupt air flow? Were calculations made for the Ranger owner or Cutwater owner that have extra gear on board using all the available space in the storage compartments to store items. Does this impede air flow? If water and moisture gets into the compartments will the air move enough to equalize humidity levels? With the generator operating at close to 210 degrees will the air in the compartment be cool enough to operate at design. Will the engine now have enough air flow to operate properly and compartment temperatures stay at levels recommended by ABYC and Volvo or Yanmar? I assume they did.

My C26 had issues with high compartment temperatures ( I have mentioned this a few times 😀 ) I was able to resolve this with adding extra ventilation to the boat and install two exhaust blowers. I copied the design from looking at many manufactures, Nordic Tug, Helmsman, American Tug, Back Cove, Sabre, Bayliner Motor yachts...... If its a power boat it has a ventilation system installed. This system not only helps maintain engine compartment temperature. It also helps with odors, moisture, mold, mildew and soot.

Rangers and Cutwaters owner's boats that I have boarded. Although most do not express the need for better ventilation there is evidence that it would help. I have seen mildew, wet compartments, area's of corrosion and rust, soot, smelled odors ( not talking about waste tank but ventilation can help with that too). I have talked to owners that have soot stains in the living spaces. Generator operation issues, ( many carry capacitors on board because they fail, burn up literally) Install larger fuse capacities ,circuit board issues, sensor failures many of theses issues can be caused from many things but one of many things includes operating in a high temperature compartment.

I was on board a Ranger Tug a few months ago that had a considerable amount of soot in the engine compartment. The Tug owner was asking about it. My first thought was he had a exhaust leak.The exhaust was leaking into the compartment. The only way out is through the engine ( intake ) there is no other way for it to be exhausted. (No ventilation) I asked if he had ever had issues with the generator? He stated yes the capacitors seem to fail. We looked at the ventilation install for the generator and it was installed backward sucking warm air from the engine compartment into the generator box and a vent hose came off the box back into the compartment. I question that, It pulls engine compartment temperature (120F to 140F air) into the box to cool a generator that operates at 210F and then expels this air back into the engine compartment? That is possibly part of the problem poor ventilation in the compartment? We then looked closer at where the possible exhaust leak was coming from. It appeared that the soot was being drawn into the engine compartment from the deck drains ???? There are two drains in the trough for the the engine compartments deck hatch. Both of these drains had a heavy build up of soot. The area around the drains leading into the compartment had the heaviest concentration of soot. I advised to troubleshoot this clean the area and tape over the drains temporally to see if this reduces the soot. If it does then inspect the flaps mounted in the transom drains. Open the storage areas up and make sure that there is enough open area to get air into the compartment for better engine air flow. If there still was an issue I would advise installing more engine compartment ventilation.

My opinion. The ventilation system was marginal at best. The Ranger tug had many cruising hours on it. The Tug owners were using the boat for what it was designed to do Cruise. They had no complaints with operation and really liked the boat. It was well maintained. They had a lot of gear on board and storage compartment were full. I believe the engine air requirement for operation was greater than what could be pulled in around the gaps in the cockpit. This created a higher then normal depression in the engine compartment. Some of the exhaust coming out of the side exhaust would trap under the swim platform and this exhaust was sucked into the drain scuppers and pulled into the engine compartment.

Ventilation in a boat is more than keeping the compartment temperature at recommended levels, keeping compartments ventilated to equalize the humidity levels inside and outside the boat, maintaining enough air flow for proper combustion of the engine and helping to reduce compartment odors. A properly designed ventilation system is to do all of theses things.

I personally do not agree with the design that Fluid Motion uses. They have built a lot of boats with a lot of satisfied customers. If there is any merit to my post I hope it is this. Understand what the engine requirements are for temperature and air needed for induction and operation. Understand where this air is coming from. Know that if areas get wet or there is high moisture in the compartments it isn't going to leave without doing something about it. If there are a lot of items stored in the compartments make sure that the items are not blocking air flow.

Well stated. One day I will attend to the ventilation in our compartment and that backward installed exhaust fan. Cruise on.

Cheers.

Thank you, Brian, for your observations. Two additional points, one on limber holes, if they are weeping brown water, there is rot in the floorboards. They are not sealed on the underside, and that's where the rot starts. To compound the water retention, the limber holes are not flush with the hull, and that provided pooling of the water and high humidity in that compartment leading to rot. Extra and large vents (2") such as plastic vents found at Home Depot that are used in venting the eves on houses are helpful. The second point on generator ventilation is I have found black soot on the monkey fur on the aft bulkhead at the joints in the cave, and on the monkey fur joints in the "V" berth. I have a Mase generator that is an air-cooled diesel but a water-cooled generator via a radiator. Should I add only passive ventilation or mechanical ventilation via a blower, and should it be blowing into the compartment or sucking out. If I have negative pressure will the generator have enough air to operate properly, or if I had positive pressure will more soot (black stuff) be pushed in the cabin. I suspect that Ranger knew this problem, hence the CO sensor location in the cave.

I installed (1) 4" and (2) 3 "Passive inlet vents and (2) 4" powered outlet vents . If I were installing a vent system for the generator. I would install a 4" hull vent (use a good grade vent hose) attached to the bottom of the Generator box cowling . Attach 4" vent hose to the top of the box then to a 150 CFM 4" continuous operation blower then this is attached to a 4" hull vent. If you are installing for the engine compartment for compartment cooling and air circulation ( moisture control, odor, and keep soot out of living spaces. Run passive inlet vents hoses to low points in the compartment and power vent hoses to high points in the compartment. This will help with air circulation, moisture, engine compartment temperature and help remove air contaminates from the compartment. The theory that compartment ventilation is only used in Gas powered boats to remove gas fumes is a incorrect theory. It is required in gas powered boats with built in tanks and recommended for Diesel powered boats. Ventilation does more than remove fumes.

Gentlemen,

since joining TugNuts back in fall of 2019, I have read a few threads containing discussion about engine bay temperatures and concerns some of you have had - very interesting. That prompted me to do my own testing on our 2011 R29 with Yanmar 260 back in June/July of 2020 and I am finally getting around to sharing results.

Test apparatus used was a HOBO data logger that we use for testing/monitoring in the HVAC industry; it's a very accurate instrument. The first test day was June 19th with ambient temp in the low 70-degree range on Puget Sound and water temperature in the normal range of 55 degrees. We cruised steady for about three and a half hours at normal cruising speed for us between 7 and 9 knots (2000 to 2400 RPM). The logger showed temperature in the engine bay never got above 98-degrees until we shut down at our destination, when the temp continued to rise to 105 because we were standing still with now air flow through the compartment. I did the same test on our return trip two days later with the exact same results.

I did a similar test about a month later, but this time I moved the HOBO to the port side lazarette, as that is where our inverter/charger are located and I wanted to see if that space was getting excessively warm for that equipment. This time ambient temp was in low 70's and again we cruised for about three hours and the temperature in that space never rose above 85-degrees.

I was happy with my testing and am currently comfortable that the engine bay and adjacent spaces where batteries, inverter and future solar controller will be located are not getting excessively warm. I will likely run this test a few more times and target days when ambient temps are higher. I realize some of you are in areas where you might regularly be on the water under much warmer conditions and therefore your concerns.

Thanks for leading the discussion on this topic.

Bryan, do you have photos of the vent installation? In the PNW I think we have little problem with heat, but general ventilation and moisture control would be good.

On a somewhat related note, I have tested reported engine temps a few time under WOT here on our C30. The usual engine temp at any cruising speed after warmup per the Volvo panel is 185F as expected. With WOT of 10 minutes or more, it doesn't change and stays right at 185F.

So I think engine cooling as such is fine for C30 in PNW (as one might expect given the manufacturer). Agreed that better plywood drainage would be good however!

SJI Sailor":2ihzs3p4 said:

Bryan, do you have photos of the vent installation? In the PNW I think we have little problem with heat, but general ventilation and moisture control would be good.

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I have several pictures of the Ventilation install in my album.

Engine cooling temperature is not really effected by reduced incoming fresh air. It is actually the opposite. Engine operating temperature increases compartment temperature. A fully enclosed compartment with sound deadening insulation and an engine operating at 185 F degrees + ambient air can increase the compartment temperature. The Lazarettes if properly ventilated should maintain outside ambient outside air temperature while cruising. This is where the fresh air is coming in. This air is pulled into the engine compartment for cooling. When testing compartment temperature the object is to find the warmest area. In my boat the difference between 1' aft of the reverse gear and 6" in front of the engine is 25 F degrees. The fwd section of my D3 is the location of the air intake and the alternator. I added blowers to exhaust air in front of the engine and behind the engine and added all intake fresh air to enter near the engine air intake. Both blowers are pulling air from the upper section of the compartment. If is a Gas powered water craft air is pulled from the bottom of the compartment. Diesels the air is pulled from upper sections. Removing warm air.. The blower in the aft section is sucking air in from the side Lazarettes pulling outside air in from the air gaps around the cockpit liner. This helps maintain air movement in the Lazarettes. I don't notice any noticeable air temperature changes in the storage compartments now.

SkookumR29":2ihzs3p4 said:

Test apparatus used was a HOBO data logger that we use for testing/monitoring in the HVAC industry; it's a very accurate instrument. The first test day was June 19th with ambient temp in the low 70-degree range on Puget Sound and water temperature in the normal range of 55 degrees. We cruised steady for about three and a half hours at normal cruising speed for us between 7 and 9 knots (2000 to 2400 RPM). The logger showed temperature in the engine bay never got above 98-degrees until we shut down at our destination, when the temp continued to rise to 105 because we were standing still with now air flow through the compartment. I did the same test on our return trip two days later with the exact same results.

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This is good information. It shows that your boats compartment is staying with in the ABYC standards of Max compartment temperature increases of 30 degrees above ambient. 72F ambient compartment temperature 98F = 26F . The more important number is below 120F max temperature. One advantage is 55 degree water temperature. The bottom is heat syncing some of that compartment temperature. Run your boat in 75F or 80F water temperatures which will be found in many southern boating areas along with ambient air temperature in the mid 80's. I don't think the results will be the same as you found. The Fluid Motion Product is sold in and used in theses environments.

Jerry what areas of the engine compartment did you test the air temperature? I would place the sensor in the fwd section of the compartment, near the alternator, then place it above the engine, then place it where the ECU is located, then put it just aft of the reverse gear all testing done with engine hatch closed record the results. The fact that you are seeing 12F to 15F increases in compartment temperatures that are not in the engine compartment leads me to believe there are higher temperatures in the compartment. I could be wrong I'm just thinking outside the Box!

Jerry thank you for your interest and checking this out it is good information. There are many more elements to good compartment ventilation than just temperature. For me temperature is important along with maintaining moisture, odors, and battery ventilation.

Thank you, will look at the photos. (And you are right, I did not mean to say that the lazarette temp would affect the engine temp. I just wanted to point out as a side note the WOT temps I have observed, because I have seen separate threads about the water intake sizes and temps, and engine cooling.)

All valid points Brian about varying water and ambient temps depending on where we are operating our boats. I'll run a few more tests with data logger in different locations as you suggest and let you all know the results. The test I did had the logger stuck right to the side of the ECU.