Operating Generator Underway

PDQ issues applicable across all PDQ Yachts (or if you can't find a place for something, it probably belongs here for now)
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1st mate
1st mate
Posts: 46
Joined: Wed Apr 17, 2019 8:55 pm

Operating Generator Underway

by Nick » Mon May 20, 2019 8:15 am


We’re new owners of hull #66 (formerly Rising Tide and now Catsaway). Lots of good info here on the forum so thank you to all who contribute. We’re from the PNW and find it pretty hot cruising up the coast of Florida right now. Sure there’s a breeze on the flybridge, but wondering if one can run the generator to have air conditioning underway. I’ve searched the forum and not found anything specific on the topic.
Nick & Barb
2005 PDQ34 #66

Posts: 749
Joined: Wed Jun 15, 2005 11:18 am
Location: ICW (32043)

Re: Operating Generator Underway

by duetto » Tue May 21, 2019 7:44 am

hi nick,

welcome aboard.

we have only run the generator once when running and that was for heat. we ran at hull speed or about 7 knots. if your real question is can i run at 13 knots with the generator running the answer is it's all about cooling. the main engines have clam shells covers with slots facing forward. this forces the water into the water pump intake. if your boat has a clam shell cover on the genset it's probably facing backwards. the reason it faces this way is to prevent water being forced into the raw water system and eventually backfilling the cylinders. that purpose tends to work against the water pump trying to suck water in when running. so my best answer is i don't know. i do have a friend with a different kind of powercat who wanted to run the generator while cruising. he had to reconfigure the clamshell to get generator to suck water.

good luck,
john & diane cummings
duetto mv34 #23

Posts: 272
Joined: Mon Sep 15, 2014 3:48 pm
Location: Punta Gorda, FL

Re: Operating Generator Underway

by deising » Sat Jul 20, 2019 5:01 am

Hi, Nick,

I am very late answering your post, partly because it was not under the PDQ Powercat Forum.

We have run our genset underway from time to time. Mostly at 7.5 kts or less and it works fine. Our genset water intake has no clamshell at all, just a hole in the hull. On two occasions, we even ran the genset at what is high speed for us (12 kts) for a brief period and had no problems.

If in your particular situation you are not getting adequate cooling water for the engine to stay cool, it should shut down automatically. If that were to happen, hopefully there would have been enough water to at least keep the impeller from being damaged.

While you don't want to run the genset too much at light load, the more power it produces, the more heat. Since you are underway with the alternators available, you could always turn off the battery charger temporarily so that the charger doesn't pull power from the genset in addition to the A/C unit(s).
Duane Ising
m/v Diva Di
Punta Gorda, FL
2006 PDQ MV 34 - hull 91, 75HP, 3-blade

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