Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 08-12-2014, 09:32   #16
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: Generator install

Quote:
Originally Posted by Dennis.G View Post
I guess I don't understand this. I certainly do not have this on my generator. How can generator water pump draw water in via a vented loop? Won't it just suck in air through the vent?
Most likely your generator is installed above the water line and does not need a vented loop to prevent siphoning. Ours is also installed this way and we do not have a vented loop.

The loop goes somewhere between the raw water pump and the water injection into the elbow, so it is on the output side of the pump, not the input, and will not suck air.

Mark
__________________

__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 08-12-2014, 09:41   #17
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: Generator install

Quote:
Originally Posted by Dsanduril View Post
If you're putting in a vented loop then you have a loop or rise in the exhaust hose, making the hose longer and creating a water lift situation. A straight, horizontal exhaust hose will have lower back pressure.

------

And yes, with an exhaust vented loop the vent is installed on the pressure/pumped side of the cooling water system. This allows water to flow through the vent system to the exhaust during engine operation, keeping hot exhaust gases from entering the vent. When shut down the anti-siphon valve still allows air into the exhaust hose.
OK, this is mixing two things - a vented loop to prevent siphoning, which is not associated with, and has no effect at all, on the exhaust system and its back pressure, and a non-vented riser loop on the exhaust hose to keep it above the waterline. The latter is does present some minimal back pressure, but is usually necessary as part of a proper installation.

A straight, horizontal exhaust hose in many (most?) installations will cause the exhaust system to fill with water in no time. I don't know of any installation instructions that suggest such unless the entire genset system is well above water line by several feet.

Exhaust gas can never enter the raw water system, and preventing this is not the purpose of a vented loop. The vent prevents the siphoning of water from the raw water intake into the exhaust system until the exhaust system fills with water and backs into the engine. In other words, it works on the opposite end of the system than you are thinking.

Mark
__________________

__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 08-12-2014, 09:57   #18
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,075
Re: Generator install

OK,
You guy's especially Mark have made it real clear, I'll get the vacuum brake even though I don't think it's necessary as it just might could be under heeling and maybe bad weather. I think calling it a vented loop is what threw me, I was thinking it was in the exhaust.
It's just not that expensive and not that big a deal.
__________________
a64pilot is offline   Reply With Quote
Old 08-12-2014, 13:25   #19
Registered User

Join Date: Jul 2013
Location: San Diego, CA
Posts: 3,157
Re: Generator install

Quote:
Originally Posted by a64pilot View Post
I intend to stuff as much Solar above my Dink on the davits as I can, but I'm most likely going to have an AC watermaker and just in case the panels are not enough or we get a hot, buggy night or whatever, I want a genset, but it will be intermittent use, not one that runs all the time.
As someone else suggested, I'd go with a gas inverter/charger. Costco now sells a 2000w unit that looks a lot like the Honda, it has a Yamaha engine in it, with a 5 yr warranty and it's only $600. Buy 2 of those and you've got about 3200w of power. I've seen a couple of them, they are as quiet, it not quieter than the Honda under load. You could run just one for battery charging, or run both for the water maker, kind of a modular approach to power generating.
__________________
socaldmax is offline   Reply With Quote
Old 08-12-2014, 15:01   #20
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,075
Generator install

I've currently got two Honda's. They have maybe 10 hours on them max, that was the plan, but they are noisy compared to a built in genset and are sort of a pain to get out of the lazarette and set up. Only way I could get it so I had no CO in the cabin is to put them in the dinghy, which is just as much a PIA as dragging them out of the lazarette.
If all goes well, you'll soon see at least one Honda with less than 10 hours on it up for sale, maybe two.

They are a lot less expensive than a built in genset though, but actually take up just as much room
__________________
a64pilot is offline   Reply With Quote
Old 08-12-2014, 15:16   #21
Registered User

Join Date: Jul 2013
Location: San Diego, CA
Posts: 3,157
Re: Generator install

Quote:
Originally Posted by a64pilot View Post
I've currently got two Honda's. They have maybe 10 hours on them max, that was the plan, but they are noisy compared to a built in genset and are sort of a pain to get out of the lazarette and set up. Only way I could get it so I had no CO in the cabin is to put them in the dinghy, which is just as much a PIA as dragging them out of the lazarette.
If all goes well, you'll soon see at least one Honda with less than 10 hours on it up for sale, maybe two.

They are a lot less expensive than a built in genset though, but actually take up just as much room
I'm sorry to hear that. I was really hoping there was an easy way to use them without CO risk and avoiding the hassles/expense of a water cooled genny. How much is this 3.5K genny going to cost? Is it a good brand?
__________________
socaldmax is offline   Reply With Quote
Old 08-12-2014, 15:22   #22
Marine Service Provider
 
AnchorageGuy's Avatar

Join Date: Mar 2003
Location: Wherever the boat is!
Boat: Marine Trader 34DC
Posts: 4,618
Re: Generator install

We installed our generator ourselves 2 year ago and have cruised thousands of mile and the genset has had some heavy use. Yes a vented loop is need in the raw water side IF the generator is near or below the waterline. The exhaust needs to rise above the waterline from the waterlift to prevent backflow. Here is a blog post on our installations. The Trawler Beach House: Do-It-Yourself Generator Install . Chuck
__________________
Chesapeake Bay, ICW Hampton Roads To Key West, The Gulf Coast, The Bahamas

The Trawler Beach House
Voyages Of Sea Trek
AnchorageGuy is offline   Reply With Quote
Old 08-12-2014, 17:17   #23
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,075
Re: Generator install

SoCAl,
About $8K , Same gen Anchorage guy went with, his write up is rather complete, check it out.
__________________
a64pilot is offline   Reply With Quote
Old 08-12-2014, 17:50   #24
Registered User

Join Date: Jul 2013
Location: San Diego, CA
Posts: 3,157
Re: Generator install

Quote:
Originally Posted by a64pilot View Post
SoCAl,
About $8K , Same gen Anchorage guy went with, his write up is rather complete, check it out.
Youch!

I didn't see any mention of air conditioning. I was thinking that I usually shoot for a genny that will be at 50% load under normal conditions, considering (hoping!) that a slightly larger genny might only cost a little more, have you considered a 5KW version, or is that one $12,000?

For example, I have solar panels, but those are used just for battery charging and 12v loads. When I need A/C, I fire up the genny (5KW on one trailer with a 15K BTU A/C, 5.5KW on the other with a 15K BTU and a 13K BTU.)

I was just wondering if you considered installing an A/C in the future and if so, perhaps a slightly larger gen might be in order, provided the price isn't sky high?
__________________
socaldmax is offline   Reply With Quote
Old 09-12-2014, 16:54   #25
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,075
Generator install

With both my 16K and the 5K AC running with the battery charger and other normal AC loads, I pull 21 amps, The little Gen is a 30 amp generator, my boat is a 30 Amp boat. Truthfully I can't see needing both AC's on at the same time.
One Honda will run my 5k Ac and charge batteries, reason I got a 5 k AC, both Honda's will run everything on the boat, but won't always start the 16K AC unless off of Eco mode.
Not a whole lot of money difference between the 3.5 KW gen and the 5.5 KW, but I don't think I need the 5.5KW, for one thing I'd have to change to 50 Amp service or I would have the electrical over rated.
I think it boils down to this is supposed to be an occasional use gen, not a full time gen., I want primary to be Solar, but the gen when needed is available, if I were to go with a gen only, Northern Lights would be the best, but that is a whole lot of weight, to say nothing of the expense.
An IP is a heavy boat and can carry a lot of weight, but I'm trying to keep the weight down, especially on the ends as much as I can, I've already got a big RIB hanging off the back and plan to add Solar.
Trying to not let myself get carried away and to stop at good enough. Intent is to use the gen rarely, not be the guy who cranks theirs up before disconnecting from shore power. Truthfully the Honda's would fill the need.
__________________
a64pilot is offline   Reply With Quote
Old 09-12-2014, 18:08   #26
Registered User
 
Terra Nova's Avatar

Join Date: Apr 2007
Location: Marina del Rey, California
Boat: Freya 39 cutter- Terra Nova
Posts: 3,652
Re: Generator install

Here's the generator manual. Read the installation instructions.
http://www.nextgenerationpower.com/I...rt/UCM1-35.pdf
Make sure it can start your A/C. Install one for the A/C if you must have that. But a 12-volt watermaker will operate whether or not you have a generator.

The vented loop goes in between the seawater cooling discharge and the mixing elbow, and is needed if the elbow will ever be below the waterline. Only drawback is that 2 holes are required in the sound shield, for running discharge water to and from the loop. And that the valve needs periodic servicing to perform as intended.

Never run marine exhaust horizontally. It must always pitch down to the outlet from its highest point. If there is any possibility of back-flow, use a seacock to insure that does not occur.
__________________
1st rule of yachting: When a collision is unavoidable, aim for something cheap.
"whatever spare parts you bring, you'll never need"--goboatingnow
"Id rather drown than have computers take over my life."--d design
Terra Nova is offline   Reply With Quote
Old 09-12-2014, 20:51   #27
Registered User
 
transmitterdan's Avatar

Join Date: Oct 2011
Boat: Valiant 42
Posts: 4,034
Generator install

If you use a water lift muffler or inline type you need a siphon break in the raw water line between the HX and the exhaust elbow. This is so even if the exhaust is above the waterline.
__________________
transmitterdan is offline   Reply With Quote
Old 10-12-2014, 07:01   #28
Senior Cruiser
 
colemj's Avatar

Cruisers Forum Supporter

Join Date: Oct 2005
Location: Presently on US East Coast
Boat: Manta 40 "Reach"
Posts: 10,049
Images: 12
Re: Generator install

Quote:
Originally Posted by a64pilot View Post
With both my 16K and the 5K AC running with the battery charger and other normal AC loads, I pull 21 amps
I suspect you have a small battery charger? If so, consider that you may find you want a larger one when out cruising. Particularly if you have a generator, where running that to power a 20-40A charger doesn't make any sense.

A 100-120A charger will draw 16A, but will cut the generator time for using it by a factor of 3 or more. This will be too much for a Honda, and you will need to pick which things are running off a 3.5KW generator. That usually isn't a problem, because you won't need to be running everything on your boat at once.

Mark
__________________
www.svreach.com

You do not need a parachute to skydive. You only need a parachute to skydive twice.
colemj is offline   Reply With Quote
Old 10-12-2014, 07:29   #29
Moderator
 
HappyMdRSailor's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: North Mississippi
Boat: 48 Wauquiez Pilot Saloon-C22 Chrysler Sunpiper- 19 Potter-Preparing to cruise w/my girl
Posts: 5,980
Re: Generator install

Pilot,

I think 3.5 is the right size for your 38... And Mark has it goin' on with the high current charger...

Oh.... And...

Did you risk installing your toilet paper holder yourself??? Or do the right thing and hire a marine professional....
__________________
In the harsh marine environment, something is always in need of repair...

Mai Tai's fix everything...
HappyMdRSailor is offline   Reply With Quote
Old 10-12-2014, 08:06   #30
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Albany Ga.
Boat: Island Packet 38
Posts: 17,075
Re: Generator install

Basically my boat is a time machine, darn near everything is exactly as it was when she was built in 1987, amazingly it all still works fine. Battery charger is a 30 amp Raritan charger, yes it will go away eventually. Good thing is almost nothing has been butchered by a PO. Installed a modern DSC radio last weekend so I'm slowly working through the systems. I don't plan on getting an integrated chart plotter / Radar until just before we go as I don't need one now. I'll probably do the Solar though as I don't see it becoming obsolete in the next two years
Way I see it is it would make the most sense to run the gen in the morning and get the batteries through the bulk phase and make water, doubt I'd need the AC then, so I'll be picking loads so to speak. I am not sizing it so I can turn everything on at once, doubt I'll need both AC's and the hot water heater all at the same time for instance.
Intent is to move with the seasons, avoid hot sticky and or cold weather, gen will be there though to keep us from becoming miserable when and if the "flying teeth" show up at night or we get several days of overcast conditions.
__________________

__________________
a64pilot is offline   Reply With Quote
Reply

Tags
generator

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Mahe 36: Generator Install rgary Fountaine Pajot 1 10-09-2013 16:49
Portable Generator vs Solar Panels or Wind Generator Sweet As Electrical: Batteries, Generators & Solar 120 16-09-2010 19:27
How to install generator mounts flying kiwi Engines and Propulsion Systems 5 12-07-2008 08:46
Any way to convert a DC Generator to an AC Generator? Latitude9.5 Engines and Propulsion Systems 13 06-04-2007 12:06



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 13:52.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.