Boxing in the engine

I am interested in everyone’s take on this so I moved it to its own topic.

I have been pondering how to create a box in our N30U that I can easily remove the walls to do maintainance. I bought the insulation, but I have only installed it on the panel to the cabin. I like the push button fix idea. https://button-fix.com/

The advantages: If insulated well, it should be quieter. It should also keep the heat away from my refridgeration unit that is on the forward end of the port lazarette shelf. It is hard to remove the calories of heat from the fridge if the air is already 140 degrees+.

Engineering thoughts: The engine puts out a lot of heat. How do I remove it? The bilge blower sucks the hot air down into the bilge then up through the vent. That brings the hot air under your floor first. Not great on a hot day. I had an extra bilge blower. The new blower draws air from right above the engine. It is very effective. Would be more so if it was boxed in. Instead of an intake and an output vent, I made them both outputs. I only use the original blower at startup to make sure I have no propane sitting in the bilge.

My thought is to keep it light. A lightweight frame and 1/4 inch plywood. The starboard wall just inward of the fuel tank. The port wall will be smaller as there is more of the wall from the closet. The stern wall will fit above the exhaust. I am not looking for anything near air tight. The air that the blower removes needs to come from somewhere.

Any thoughts and photos of a boxed in engine would be appreciated. Even if they are from other models

Chuck Garbarino

In my 26C there are clamshell vents on the aft end of port and stbd coamings. One is ducted from the exhaust fan outlet (which sucks air out of the lowest bilge area to exterior). The other is a fresh air intake to engine room/bilge. So fresh air is replacing the exhausted air. If your new fan is vented to exterior same fresh air supply should keep incoming air cooler than engine room. Maybe use insulated ducting if you think that exiting air is too hot inside the boat??

Here is a photo I found in my files from the listing when I bought the boat.

The green and red arrows point to the starboard and port sides of the “box”. I think these sides would be there whether the engine was fully boxed and insulated or not. But perhaps another NS33 owner could confirm that. The yellow arrow points to a door in the aft bulkhead of the box. That bulkhead is very close to the engine so that when you remove that door the (rear-facing) front of the engine is very close. I think this bulkhead may be “optional” but again, perhaps another NS33 owner could confirm that. The cockpit deck has a large removable hatch encompassing everything between the binnacle and the cabin bulkhead, but it is bolted down and lined with sound insulation. The “engineroom” door, which has been removed in this photo, is also lined with sound insulation.

If you imagine that port (red) side of the box as a bulkhead running almost to the transom, you can imagine that working on the front of the engine is somewhat uncomfortable. On the other side of that bulkhead is a large storage and misc space. (My refrigeration equipment is in about the same location as yours and does not have trouble with heat. But the engine box is not externally vented and I rarely run the engine for more than an hour and usually much less than that.) To access the front of the engine - like to change the impeller - you climb down into that space through the port cockpit seat and the open a door in the (red) bulkhead. Through that door you will find the aft side of the door in the aft bulkhead of the “box”. It’s a bit awkward, but man does it give you a lot of space that is separated from the engine.

I have no idea if this is helpful or not, but I hope so.

A diesel engine is a giant air pump. It sucks air in the intake and blows it out the exhaust. I doubt any small fan you put on a boxed engine would actually be able to draw any air away from the engine and if it was powerful enough it would likely be detrimental to good combustion.
If you want to cool the engine leading cool outside air in is a better idea than trying to blow hot air out.
…IMHO

Thanks for the picture and detailed description. Was your boat a Wiggers build or Hinterhoeller? The hatch in the cockpit soul should also make it easier to service the engine.

Good idea moving this to it’s own topic.

Most boat engines are boxed in pretty tight and have just a couple of openings to feed it air. I suspect they get pretty hot in the engine boxes and that they really do not care. The engine block is at some crazy temp and it probably does not care if the surrounding area is also that hot. Perhaps it will shorten the life span of hoses, belts and wires, but only minimally - how hot do you think the belt on the engine is after running for a 1/2 hour?

On our 30U, we would have air coming in from the cabin (through the grating at the foot of the companionway) and through the one clam shell vent (ours has a hose on it that I would pipe into the box). I don’t think you can really count the various little openings that would be in any surround we build unless you add additional clam shell type openings to provide air. While not a bad idea, I would probably trip over them - my feet have learned the deck and any additions now could be disastrous. I would plan on also piping the exhaust hose to the box as well.

I figure I would build a surround out of ¼” ply (heavier ply if you plan on hanging things from the panel - say your emergency tiller?), painted over with epoxy to seal it all. Type 2 Button Fix bonded to the hull at the bottom, type 3 at the top, slots cut in the wood for the various wires, etc. that need to go through. Attach sound insulation. Maybe attach a couple of handles at the top to grab the panels to remove them. Biggest problem will probably be the stern – lots of stuff back there that needs to go through – wet exhaust, steering cables, bilge hoses, battery cables. The stern panel may make more sense being made permanent.

Neither. Sort of. It’s complex.
As I understand it, the boat was ordered from Hinterhoeller in 1994 and pre-paid. Then Hinterhoeller went bankrupt before it was completed. The bank tried to claim the boat as an asset of the company and the buyer fought them in court for two years before he got possession of it. He then hired much of the original Hinterhoeller work crew to finish the boat out to their usual standards. The buyer was also a third-time Nonsuch owner and so there may be refinements due to his prior experience. The way the engine is boxed might be one of those. I don’t know.

The hatch in the cockpit sole would make it easier to service the engine if it were not bolted down. It can be unbolted, but by the time you’ve gone to that trouble, you might just as well have done the work through the little doors. I will unbolt it if I ever need to do major work or (oh no!) remove the engine entirely. It will come right up through the very generously sized hatch.

Regarding Lloyd’s comments. The box around my engine is open at the bilge level just below that door in the aft bulkhead. The engine is thus well-supplied with relatively cool air. He is correct about the engine being fine in a hot box. And since the engine is water cooled as is the exhaust, it probably doesn’t get much hotter than that in there, so the rest of the stuff in the box is probably OK, too. It’s been there for 30 years and I don’t see any unexpected deterioration (aside from the sound insulation on the underside of the cockpit hatch!) so I’m not worried about it.

You should consider 3/4" and secure it well. Once you’ve got that plywood around the engine you are going to find it very convenient for attaching smaller equipment. If you look in that photo, there are fuel filter and intake water strainer on the port side. And a light with its own switch. Be sure and put that light in. It’s awesome.

Wow, Vela looks like a transition build between Hinterhoeller and Wiggers. I know Wiggers bought the molds and plans when they were a start up but I bet they hired the skilled workers as well.

I want to specify my goals here. I am not looking to cool the engine. I want to remove the hot air from the lazarettes. Currently, the engine compartment IS the lazarettes. My refgridgeration unit is in there. A few years ago we ended up with a 10+ hour motor due to calm winds. The compressor ran almost the entire trip. The temp in the lazarette (engine compartment) was pretty high. The bilge blower air to replace what the blower draws out will be replaced with the air from the bilge. If I find it needs more, I will add a 3 inch vent, port side, as low as possible so the cooler air will come in low and the hotter air will go out high.

I should not need to hang engine related components from the box walls. Currently all of that is mounted to the exterior wall of the closet (port side). That is why I was planning to go light weight. I want to be able to remove the panels easily.

Brian G, I would love to see a photo of the outside of the box. From the point of wiew of someone sitting in the Lazarette. That is how I have to go in to replace the water pump, clear the strainer, open and close the seacock, alternator, belt, etc. That is all on the starboard side. There is not much to get to on the port side that I cannot reach from the cabin (front).

Thanks,

Chuck

I’ve never heard “Wiggers” in association with my boat. (Not to imply that there’s anything wrong with Wiggers!) As I understood it, all moldings, keel, and some other major parts were already made and/or acquired by Hinterhoeller before they went backrupt. They just weren’t assembled. I’ve actually talked to one guy who was on the finishing crew and I got the impression that it was just an ad-hoc assemblage of the old crew from the factory. They took what they got from Hinterhoeller and sourced the rest from the same suppliers as original. The interior woodwork is mostly to the design, but with some minor custom touches.

But I could be totally mistaken on any and all parts of the story because it’s just an accumulation of stories and hearsay and such. I know there are current Nonsuch owners who have owned their boats since before that time. There wasn’t all of this social media back then, so maybe nobody knew what was going on, or maybe they did. The boat won some sort of overall prize at the Nonsuch nationals in 1997, so maybe people sat around and chatted with the owner about his ordeal at that time. If so, I’d love to hear about it.

Back to the thread…
My reference to cooling was that the engine box is going to get hot inside. If you don’t remove the heat it will find its own way out. Heat moves from where it is to where it ain’t. And hot air rises, so not much is going to go out through the hull. Most will go up through the cockpit sole or through the sides of your enclosure. The progression of the heat through the sides and top of the box will be much slower than you are accustomed, to, so the vents in your lazarette will probably have time to remove most of it and keep that area much cooler. As I said, my refrigeration equipment is in roughly the same place as yours and it keeps my large refrigerator bin quite cold at a setting of 4 (on a 0-7 scale).

A useful photo of the bulkhead from inside of the lazarette may take time. Here’s what I’ve been able to find on my computer. Not great, but hopefully helpful.
You are in the lazarette looking forward toward the aft bulkhead of the engine box. You can see the access door (with one of the toggles unlatched!) Remove that and there’s the engine. But it is impossible for me to get into this space, I was just looking in from the area near the transom. To access the engine you must lean in through a door in the port bulkhead.
So, look at the red arrow. It points to that access door. That port bulkhead goes from hull to the bottom corner of the cockpit sole and from the cabin almost back to the rudder post. It seems to be structural to me. The green arrow points to the matching bulkhead on the starboard side. On the other side of it is the quarterberth - as apparently is true on yours, too.
It appears that the only actual boxing that was required was adding that aft engine bulkhead with the door.
Oh, the gray arrow points to the exhaust hose. Those white hoses above it are for venting fumes. The plywood is not fitted carefully around these, but the sound isolation material is.

This is the only thing I’ve got looking at the bulkhead from inside of the lazarette. It’s a clip I took out of a longer video that I took for a different purpose and most of it was not relevant. This is the lazarette side of that door that the red arrow is pointing to, above. So the bulkhead directly ahead in this video is actually kind of even with the aft engine-box bulkhead.


(If it looks kind of battered and dirty in there, it’s where fenders go, so maybe that’s why. It came that way and I’ve never really thought much about it until seeing it in this video.)

Suggestion - on Aloki I had a similar issue with heat in the engine area. To help resolve the issue I installed two of the above fans with ducting wired to the ignition switch such that when the engine runs these two fans run.

One is positioned to an ‘intake ‘ clamshell on Stbd and the other to an ‘exhaust ‘ clamshell on Port. I pointed the intake side to my alternator and exhaust near the reefer which is also mounted on the port upper shelf. I was also able to obtain a hood for the coil side of the reefer which is ducted passively from another clamshell on the port side and faces into the wind. Overall temps dropped 20/30 degrees depending on outside temp and length of engine use.

A thought for your idea - why not ‘box’ the condenser with a fan powered fresh air intake duct from outside. Positive air into the enclosed area might help cycle the unit less. Wire to key switch and have small ‘exhaust’ strips at bottom of reefer box. Air flow will help a lot.

Move the fridge compressor, the engine area is the last place to locate it.

Under the sink or stove top if you don’t have an oven. You need to pull air from the coolest spot you can access and vent it to the engine room

Enclosing the engine will increase the temperature of the engine and possibly reduce the air intake.

IMHO enclosing it will do little to reduce noise and vibration . I removed my engine insulation a few years ago and it made no difference in noise or vibration…

I agree with Thor. Much easier and more efficient to move the refrigeration unit than box in engine. Mine is located on small shelf built behind stove, right next to cooler box, on my 30U.

When I got my boat 6 yrs ago, the insulation on the engine panel under companionway steps was deteriorating, so I replaced it with new stuff 2" thick. I found no significant noise reduction, and it just makes the panel much heavier to move inside boat. Waste of time and money, I now wish I’d never done that.

I believe the question Brian asked was an opinion on boxing his engine area in . I believe it was to potentially reduce the temp around his reefer compressor. I know of a Nonsuch 260 that had its engine area completely boxed in by the factory and it seems to be a quieter running engine as well as a cooler environment for his reefer compressor in his port locker. He too has powered in/out vents which assist.

The suggestion was made to move the compressor into the main cabin area. Having seen compressors located behind the stove or where most install their batteries under a settee - I can recall that the heat generated along with the noise in the main cabin ( at night) is not pleasant . But a valid idea.

In my install ‘Frigaboat’ noted their compressors could be located in the engine room and offered a cowl that fits over the coil ( the more important part to keep cool) that could be ducted into the main cabin or to fresh air via an outside source . Combined with the two air blowers the reefer runs quite well and after initial cool down runs infrequently during engine operation . Draws about 2/3 A when on.

Point is , there are many different installations , ideas shared /installed , employed and enjoyed by we lucky Nonsuch owners. If it works for you - great. Regards …

Correction

Charles , not Brian .

The other issue with putting the frig compressor is the lazarette area is it is long run to the evaporator and that’s going to reduce performance.
In the east engine rooms get well into the 90’ s so short of running a couple of bilge fans, ducting the air into and out… that’s going to be noisy and draw power.
I may have an extreme example but my Frigo Boat 35 is tucked into the corner under the sink, draws air from the area around the fresh water tanks. I simply drilled a hole through the rear panel . In the PNW where is rarely above 75 it draws 18 amps a day runs for 5 minutes 3 times a hour . You hardly hear it running.
It seems like a lot of work to box in an engine, run bilge fans and have a compressor running at the end of its range….

When I put the compressor under the sink I did have to fabricate loovers on the door to allow the warmer air to escape. I did consider a muffin fan as well but it has proved to be unnecessary

I have read that a fan blowing on the alternator is a good idea if you have a larger alternator and it’s running near capacity against larger AGM battery banks. They can get very hot.

But with solar the rational for anbig alternator is losing traction.

I think that probably depends on how the boat is laid out and which refrigeration equipment you have. In my boat, the fridge is at the aft side of the galley and there is just a plywood bulkhead and some foam between it and the lazarette. My Nova Kool system sprung a leak a while back. It used old refrigerant so I replaced the whole thing. The compressor comes pre-charged with coolant. The “plate” (the part that goes inside of the fridge and gets cold) comes with the lineset all attached and pre-charged. Connecting them opens valves in the connecting hardware. Very convenient, but this means that the lineset is a pre-set length. So I ended up coiling the excess line and screwing it to the bulkhead (just like the old one was.) So it really wouldn’t have mattered where in the galley the refrigerator was, the lineset would reach it and the length and performance would be unchanged.

On the other hand, if you were inclined to install it in the cabin, the Nova Kool compressor is so quiet that it’s hard to imagine it being annoying. In fact, I doubt that I could hear it over the hum of my battery charger.

The compressor comes with a12 for copper line. It comes pre loaded. 12 feet is 12 feet, could our extended.

I hate spellchecker. 12 feet is 12 feet. Coiled, or straight.