Mounting a genset

[Snotter]

I managed to snag a 7.5 kw Onan diesel genset off of ebay. Installing it will take some time. The first major portion of the project is to epoxy and glass in mounts in the engine room (after re-locating a bank of batteries). Can anyone give me scantling recommendations and/or reading material references.

The generator is powered by a 3-cyl diesel. The complete genset weighs ~450 lbs.

 

[Snotter]

Would kiln-dried pine expoxy-glassed to the hull be adequate? I would run the front of the stringer-mounts to a forward bulkhead and taper the aft edges to runout to the hull to prevent a hard-spot. I'm not planning to encase the engine stringers in glass and am planning to make the high mount only as thick as needed to hold some fairly large lag bolts. Does anyone see any pitfalls with this approach?

 

[woodster]

Would kiln-dried pine expoxy-glassed to the hull be adequate? I would run the front of the stringer-mounts to a forward bulkhead and taper the aft edges to runout to the hull to prevent a hard-spot. I'm not planning to encase the engine stringers in glass and am planning to make the high mount only as thick as needed to hold some fairly large lag bolts. Does anyone see any pitfalls with this approach?

Snotter...were is Rodgersville in relation to Mobil or Fairhope...i may have some teak that you can get to do this with ....pm me if you like...

regards

woody

 

[Snotter]

Woody, thanks for the offer, but, unfortunately, you are too far--besides, I'd save the teak for a more visible boat project outside the engine room ;-).

 

[Alex Dare]

beds

Keep in mind, pine is a fairly soft (and rot prone) wood which might make it less than idea for holding lag bolts long term. I'd pick maybe a different wood and would fully encase it in multiple layers of roven woving. That would make the beds much more robust and structurally secure. If you plan on adding a hush cabinet you'll need to figure in a shelf that the bottom of the cabinet can rest on.

 

[Snotter]

Keep in mind, pine is a fairly soft (and rot prone) wood which might make it less than idea for holding lag bolts long term. I'd pick maybe a different wood and would fully encase it in multiple layers of roven woving. That would make the beds much more robust and structurally secure. If you plan on adding a hush cabinet you'll need to figure in a shelf that the bottom of the cabinet can rest on.

Now we are getting to the heart of my concerns. What is stated above makes a lot of sense.

The genset is mounted on an oil pan. It has a small 3 cyl diesel engine. I don't have to worry about mounting the genset like an auxillary engine.

There are exposed pine cross members in my engine room that still look good (the boat was built in 1980). I would like to believe that encapulating pine in epoxy and glassing the result to the hull (no roving or mat) would be adequate; however, I would love to cut corners when grinding class in confined living spaces (I live aboard). I need reality checks.

 

[ronbo]

Fischer-Panda recommends mounting on a metal plate 40% of the generator's weight.
I don't know of any installed like that which accounts for most installation's noise and vibration.

Ronbo

 

[CarlN]

I'd use Douglas fir (cheap, great bolt holding, and rot resistant) painted with a couple of coats of Cuprinol or CPES epoxy for extra rot protection. I'd make them 4" wide to cut down on vibration. 2x4's laminated with epoxy would work great. I really like West's thickened gflex epoxy for bedding. It's flexible enough that it doesn't crack. I'd be tempted to just bed the stringers in thickened epoxy (you've got a lot of surface area) with no glass and then paint the exposed wood for looks. You could always add some fiberglass tape tabbing later if there was any sign of separation or you just like belts and suspenders.

Carl

 

[Snotter]

Carl, I like the way you think. I've got plenty of Raka epoxy, mat, and some roving. Also, I got plenty of thickeners. I don't mind glassing; I do mind grinding inside a boat I live.

The hard part associated with the mounting process is going to be relocating a bank of batteries and building new battery boxes. I plan to get rid of 1 of 3 4D batteries since such a large bank shouldn't be needed with a generator aboard. The bank of batteries (3 group 27s) will be moved to the location where a single 4D resides.

It is surprising that neither Calder nor Casey seems to discuss the process of generator mounting other than to mention choosing a good location to facilitate clean, cool intake air.

 

[Mike1956]

A good way to avoid sanding or grinding fiberglass is to use a piece of waxed paper over the glass while it is still wet, then use your fingers to smoothe out the work. Leave the waxed paper on until the epoxy sets, then peel it off.

 

[kenn]

It is surprising that neither Calder nor Casey seems to discuss the process of generator mounting other than to mention choosing a good location to facilitate clean, cool intake air.

Not to me... each boat is going to be unique as to where you can mount the genset. The common denominator is to provide a good location with enough structure for secure support of the genset, ideally on isolating mounts. Usually the genset's installation instructions provide these details.