Calling on engineers for help. Installing 3.5 kw diesel gen in 1989 Catalina 30 MKII

[Tim Shirley]

Good evening all! Im looking for assistance please. Im in the final phase of installing new 3.5 nextgen diesel genset in port lazarette sail locker. Need to fabricate support system to mount generator to hull.. but hull liner rises so no flat mounting available. I need a raised rail or plateform base to secure it... so bolt on wood stringers, or fiberglass in? Perhaps aluminum fabricated brackets mounted on rubber pads? It weights only 165 lbs. Dimensions are 18"width x 30" length and includes sound enclosure. Unit has internal rubber motor mounts already but thinking of mounting base on second set for vibration reduction. I would like it low mounted in locker for balance.. these are older pics of locker. Already completed are the electric, fuel line, starting controls mounted, exhaust hose. Anyone have a c30 with permanent mounted gen with pics? Thanks always! Tim.

[Davo1404]

That is a large amount of weight to be putting in the aft corner of a 30 ft yacht. I know that The Catalina has a pretty wide stern, but would be dubious about the structure to support it. Have you tried the Catalina owners forum, or Catalina themselves?

[Nineteen]

Hi
This is how I put a Whispergen MGV-5 in our C380. I made stringers and glassed them in. I then made a deck out of HDPE which has worked out well.
Cheers
Tom

[Nineteen]

Hi
BTW it is 4.4kva and weighs 67kg.
Cheers
Tom

[guyrj33]

mount it as far forward and as close to the centerline as you can.
Run your stringers over as long a distance as you can, I have concerns about mounting to the liner as opposed to the hull itself. I suggest trying to fill the gap between the liner and the hull with thickened epoxy in the area under the stringers.
DO NOT use polyester resin, the secondary bods formed will not be strong enough to secure you generator under scary conditions.
I would build the stringers with multiple layers of bi-axial glass with each layer extending further out from the base. Widest layer goes down first. you could core the stringers with hardwood such as White Oak or with foam. With a foam core you'll need to make the top layers a little bit thicker to fasten the motor mounts. Lots of options for fastening the motor mounts to the stringers. Angle Iron, all bolts into wood core, threaded holes in thick fiberglass.

Good Luck

[Cheechako]

Many ways to skin that cat. The stringers shown in post 3 is what I did once to make a platform for my home built 12V diesel gen. Similar to yours.. And Poly resin was fine. (Just as it was for repairing hulls for decades. One side of the boat in my avatar was recored and glassed with poly...1 ft x 10 ft, 25+ years ago. No detriment)
But you could just make risers to go under the motor mounts rather than the whole platform. However I like more area to distribute the stress and vibration.
or
Thru bolted (not screwed) heavy duty cleats and a thick ply platform will work too. Assuming you have surrounding structure to do that (not the hull!)

[waterman46]

Originally Posted by Davo1404

That is a large amount of weight to be putting in the aft corner of a 30 ft yacht. I know that The Catalina has a pretty wide stern, but would be dubious about the structure to support it. Have you tried the Catalina owners forum, or Catalina themselves?

Same weight as if I were to go sailing with the OP and happened to sit there!

[Brewgyver]

Originally Posted by waterman46

Same weight as if I were to go sailing with the OP and happened to sit there!

Yes, and your weight would be higher, as well.
While there may not be a large number of C30s with gensets, there were over 6,000 made, and many of them have that locker filled with enough crap to be equivalent. When I bought my '78 vintage Mk I, it had a hefty stern anchor with rode and the water heater located in there, for starters. The two of them alone total over 140 lbs.

[garyfdl]

First question: what the hell is on that 30' boat that you need 3.5Kw to power it? The backup gen I have to power my 2700 sq/ft house is that big! We've uses a Honda 1Kw 'suitcase' gen for years on the boat/camping and it was more than adequate.

Second: as an engineer (albeit hydraulic design) I would talk to the mfr about where to locate the unit. Gen sets vibrate (yes, even through those little vibration isolators that serve as feet) and you want to be careful about having that vibration transmitted to the hull or liner. It will cause fatigue and that can result in structural failure.

Lastly: I would agree with guyrj33 and go with epoxy and not resin. While resin might work, epoxy is stronger and gives a better bond, assuming the substrate is properly prepared.

[Shrew]

Originally Posted by garyfdl

First question: what the hell is on that 30' boat that you need 3.5Kw to power it? The backup gen I have to power my 2700 sq/ft house is that big! We've uses a Honda 1Kw 'suitcase' gen for years on the boat/camping and it was more than adequate.

I don't believe anyone makes an internally installed generator any smaller than 3.5Kw.

I've used a 2Kw Honda suitcase for 13 years. I can't run the water heater and the battery charger at the same time. This means I have to heat the water, THEN charge the batteries. To me, it's more about how much time I'm a slave to the genny. I'd love to be able to cut the run time down and spend my time doing other things.

Also 'boat/camping'? Polite Pass.

[garyfdl]

Originally Posted by Shrew

I don't believe anyone makes an internally installed generator any smaller than 3.5Kw.

I've used a 2Kw Honda suitcase for 13 years. I can't run the water heater and the battery charger at the same time.

Water heater got it. My bad.

We're still doing it the old fashioned way, heat water on the stove, take a bath in the lake.

[MicHughV]

an oft forgotten aspect of installing something heavy (like a diesel generator) in a cockpit locker or anywhere else off center is it that it has the potential to put a boat out of trim....yes, I know, cockpit lockers get filled with all sorts of heavy stuff...

but...

case in point...my Beneteau has a builder/manufacturer installed diesel generator in the aft cockpit locker...unbeknownst to me at the time of purchase, was the fact, that several large chunks of lead had been fiberglassed into the hull behind and adjacent to the nav table (which is on the opposite side of the genset) to provide a counterweight to the generator.

This was brought to my attention when I happened to be on an identical boat, that had a user installed generator under the cockpit seat, same location as mine. That boat had a noticeable list to one side and for the longest time I could not ascertain why, until I was rewiring some stuff on my boat and came across the lead weights.

'jes sayin'....sumptin' worth looking into......and that installation noted by " nineteen" as about as good an installation as I've seen. kudo's to nineteen for a nice, simple and clean installation and if the boat now has a listing problem....see above.

a final note, my generator, is mounted with rubber feet inside a sound box which is mounted to a stringer arrangement as noted above. When running, it is barely noticeable, either by sound or vibration.

I can't say for sure, but most generators I've looked at were supported by rubber mounted feet supports, much like any diesel engine.

[Nineteen]

Hi

In regards to the weight distriibution, on our boat the galley, fridge, and midships water tank are all on the port side - hence fitting the gen in the starboard lazarette. I agree that it is no worse than someone sitting at the back.

As for resin choice, I went for a vinyl ester as that is what the boat was built with. I got a chemical and mechanical bond. It is not coming adrift. This will also work with polyester resin but is more fire resistant (heaven help any of us if it starts to burn...).

I think that provided that you can fill the gap between the liner and hull if there is one (Catalina are very goood at building boats) then you will be ok bonding to the grid if you remove the flow coat.

I would not fit a second set of elastomeric engine mounts as you are just as likely to create a harmonic resonance. Mount your generator on a solid mount and it should be ok with the supplied mounts.

Cheers
Tom

[MicHughV]

This is probably neither here nor there, my Beneteau is the 432 model, but whilst looking for a new boat, I also looked at the larger Beneteau 473....this particular model Beneteau 473 had the genset mounted in the aft lazarette area....exactly how they got it in there I could not say....but what was noticeable was that that the lower edge of the transom was dipping below the water by several inches. Typically, the Beneteau transom is out of the water, being your typical French planing hull..but not this one......a transom dragging in the water is a cause for detrimental sailing performance.....the Beneteau has a water tank under the forward v-berth and it's possible it was empty at the time of my viewing, causing the stern to drop lower.

Most yachts of all sizes pile on the weight with various and sundry personal stuff and boat detritus, often to the point of making the waterline disappear. Yes, me, guilty :-(

Getting picky, yes, possibly, but thought I would throw this out there.