Engine box ..?.

HUNTHARD

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With all factors being equal, such as sound proofing, thickness of glass ect. How much louder would a motor under an engine box be vs. one in a bilge. Some boxes are lower than others, are the lower ones quieter than more elevated ones? I am not a big fan of them due to the loss of space but are there any other draw backs? Are boats worth less given the same boat without a box vs. without? Is sound an issue or the only issue or is resale value an issue too? Is there a benefit besides maybe being easier to work on? i have never been on a boat with one and in my search I am running across some really nice boats that have them and I am curious to what everyone thinks.
Thank you,
 

hntrss

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All I can tell you is that mine is freaking loud. Come off this thing with my head ringing. I cannot wait to finish fishing and fire up my sawzall. It is a crappy design, with heat insulation, no sounddown, so it could only be better but it has got to go. I am going to see how low of an engine hatch I can get away with. I would much rather have a 6 inch high hatch I can walk over as opposed to the ridiculous waste of space this box provides. As far as what they bring to the table...uncomfortable seating. Just watch some poor fool try to be comfortable sitting on a big flat surface when its shitty out. As you can tell, I HATE my engine box. My last two boats both had little step ups and sound down, there is no comparison at all in noise levels. I think when you are flush to the deck, engine noise shoots out to the sides, in a box its like being inside of a bell. You could hold a conversation at normal levels on my Fitz and my RP, on this Duffy you can't even talk.
 

MBILL

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The key to living with an engine box is good sound insulation. I've been on small boats with engine box/poor soundproofing that were absolute torture. One guy I know reworked his engine box and sound insulation and the result was a huge improvement.
If I had to live with one I'd put on all the sound insulation that would fit and rework the air intakes as much as possible.
On a larger boat I'd see a box as a liability if it was possible to build without it.
 

toolmaker

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interesting topic. for me. I have an engine box that I am going to cut down in height. the mfgr per request of the original owner made a massive 2 pc structure that served as engine box, seat and also storage and it must go. my plan is to cut it down to the helm step up level and then mount a removable cooler and tackle center on it. so the question is what is the best sound proof material to use and will a lower engine cover be quieter ? Once cut down I will have enough of the existing sound proof material to make two layers on the under side of the cover. will multi layers help reduce the sound or after one layer are you past the point of no return ?
 

hntrss

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I know it is expensive, but the heavy sound down is the best stuff I have seen. There are other methods, but the quietest boats I have owned and been on all use sound down. The tighter you fit it the better it works too. That's the way I will be going for sure. Not sure if multiple layers helps or not, but it will make your hatch heavy with one layer, two may be a bit unruly.
 

HUNTHARD

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Guys thanks for the feedback, I am going to really try and stay away from them. I hate loud boats and I hate the waste of space. Why do 35 plus foot boats even have them? Are they too far forward. Moving an engine back must be a big job. Motor mounts, shaft angle, transmission. Idk, doesn't make any sense why a boat in the mid 30's would have one.

Thanks for all the info guys!!
 

tunaorlater

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Generally speaking the further aft the motor is the more need for a box.
 

eb tide

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I actually just took the engine box out of my 28 footer and brought it into the garage, and started to sand. My plan is to fiberglass, re paint and install soundown on all walls. I am glad this thread was started. I was going to order 2 inch soundown, do you think that will be enough or should I go thicker. There was never any type of insulation in the box so is am excited to see if this will make a difference.
 

hntrss

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Oh it will make a difference for sure. Buy the best you can afford. I thought it only comes in 2 thickness' though. Make your seams tight and use that shiny hvac tape that has the peel away backing to cover cuts and wrap around any exposed cut ends.
 

Keelboater

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I actually just took the engine box out of my 28 footer and brought it into the garage, and started to sand. My plan is to fiberglass, re paint and install soundown on all walls. I am glad this thread was started. I was going to order 2 inch soundown, do you think that will be enough or should I go thicker. There was never any type of insulation in the box so is am excited to see if this will make a difference.

I'm not sure if you are referring to the acoustic foam or the vinyl/foam products by Soundown. I would recommend using the vinyl/foam for any motor noise reduction. The heavy vinyl sheet is a substitute for the old lead lined barriers, but they might even still be making the lead ones. Now those are heavy and for a motor box would most likely become a problem. Here is a link to their vinyl/foam product.
http://www.soundown.com/Section 2 PDFs/2.1 PDFs/Vinyl Foam.pdf
 

captainlarry84

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In addition to soundowning the box. A good rubber gasket on the edge of the motor box to where it touches the deck will also help. Another big helper is a good headliner. The headliner will adsorb the sound as apposed to having the sound bounce off of a hard surface.
 

eyschulman

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So here is the most expensive solution to the engine box in the middle of the cockpit. Install two smaller engines in large boxes that make seats or beds with a central path. This can be a twin prop or single midline. Now you can run fast on two motors or slow and cheap on one. With the boxes open and a hatch in center path you have good access.

DSC_0028.jpg
 

dthompson004

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Good information everyone, question related to engine box, I'm in the process of adding additional sound barriers like described here, in my 30 Sisu and I am also adding additional ventilation to the engine. Has anyone ever used forced ventilation like a small blower motor to keep the engine fed? My plan was to have four 3 inch vent lines plumbed as close as possible to air intake wondering if its worth putting an in-line blower on a switch on one line. Its a 2009 6.0 crusader and with current two vent lines seems starved for air.
 

petrel

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And there goes your cockpit. Part of the beauty of a (real) downeaster is the deck space and the simplicity of a single engine installation. Of course the single also gets the prop down deeper to make it a better sea boat. I've got a big Maine boat w/ twin engines. It's nice to handle around the dock, but a single would do better in the seas we run in. If I could ever afford to build a big boat (50' to 55'), I would probably go w/ a single.
 

eyschulman

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And there goes your cockpit. Part of the beauty of a (real) downeaster is the deck space and the simplicity of a single engine installation. Of course the single also gets the prop down deeper to make it a better sea boat. I've got a big Maine boat w/ twin engines. It's nice to handle around the dock, but a single would do better in the seas we run in. If I could ever afford to build a big boat (50' to 55'), I would probably go w/ a single.

If the two motors are hooked up to a single midline shaft you still have the traditional DE configuration. You do loose cockpit floor space no good for a commercial boat but a pleasure boat picks up two day beds and lots of cockpit seating.
 
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