Air Conditioning for the TomCat
- Thread starter Mike...
- Start date
Way back, long ago, on one of the early TomCats, someone posted pics of an insulated exhaust system for a genset located in the live well area and it looked very expensive and took up a lot of room.
Mike, I had several worries about putting a gas genset in a small metal box and consulted several designs used in semi-truck cabs, etc.
I don't know what is intake or outtake now, but I thought that grill around the muffler under that large flap was the outflow of air, not the intake. In any case, I did not want the hot exhaust exit inside the box.
The outboard cables and fuel lines on my boat are very close to the swim step and I wanted to have some sort of protection between the hot exhaust and all of that delicate and explosive equipment, so that was the major reason for the large flap. It does serve to protect from rain and sea water.
I am amazed at how little problem sea water has been in this installation. You can see it coming right up on the top of the Armstrong surfaces at times, but it just runs right off quickly through the drains and this large opening in the photo. I had considered raising the generator with a floor platform in there, but the water has not risen above the rubber feet so far.
Originally, I had to cut the huge hole in order to get that huge 30 amp yoke to fit in, but having the exhaust end of the genset right out in the open outside air seems to be keeping the temperature inside the box nice and low.
That flap also deflects the exhaust flow down ward and aft which I am thinking reduces the chances of much carbon monoxide blowing up and over the transom into the cockpit.
I put one of those cheap, fuzzy, thin rubber bath mats you get at Wal-Mart down in the Armstrong bracket surface to dampen any vibration and it is working well. I put 6 3/8 inch SS bolts through the bottom of the box into the Armstrong bracket, but four would probably work just as well.
What does not show in the photos is that I put a full length, 3 inch high, screened vent across the bottom of the forward wall of the box to allow cool air intake with little chance for water intrusion. I also wanted a natural venting action should gasoline be spilled inside the box.
John
Mike, I had several worries about putting a gas genset in a small metal box and consulted several designs used in semi-truck cabs, etc.
I don't know what is intake or outtake now, but I thought that grill around the muffler under that large flap was the outflow of air, not the intake. In any case, I did not want the hot exhaust exit inside the box.
The outboard cables and fuel lines on my boat are very close to the swim step and I wanted to have some sort of protection between the hot exhaust and all of that delicate and explosive equipment, so that was the major reason for the large flap. It does serve to protect from rain and sea water.
I am amazed at how little problem sea water has been in this installation. You can see it coming right up on the top of the Armstrong surfaces at times, but it just runs right off quickly through the drains and this large opening in the photo. I had considered raising the generator with a floor platform in there, but the water has not risen above the rubber feet so far.
Originally, I had to cut the huge hole in order to get that huge 30 amp yoke to fit in, but having the exhaust end of the genset right out in the open outside air seems to be keeping the temperature inside the box nice and low.
That flap also deflects the exhaust flow down ward and aft which I am thinking reduces the chances of much carbon monoxide blowing up and over the transom into the cockpit.
I put one of those cheap, fuzzy, thin rubber bath mats you get at Wal-Mart down in the Armstrong bracket surface to dampen any vibration and it is working well. I put 6 3/8 inch SS bolts through the bottom of the box into the Armstrong bracket, but four would probably work just as well.
What does not show in the photos is that I put a full length, 3 inch high, screened vent across the bottom of the forward wall of the box to allow cool air intake with little chance for water intrusion. I also wanted a natural venting action should gasoline be spilled inside the box.
John
Any generator in a box needs good air flow over the generator/alternator coils. Even the water cooled marine units, often have to have blowers put in a box, if you totally enclose the unit. I haven't looked at the Honda (other than changing oil and clearing the carb)--but I suspect that there is some fan pushing across the electrical part of the generator.
It is interesting how much of a quandary this generator is causing me. Mostly because I want to mount it permanently somewhere and be done with it. I really don't want to haul a 75lb. generator around every time we head out to the boat.thataway":3n4az1oy said:
Mounting it on the Armstrong bracket appears to be the logical choice, but that's the easiest way onto the boat. Maybe it would work if I built some sort of hinged platform with legs that we could fold down over the top of the generator to use as a step while boarding.
I also pondered perhaps getting a stainless mount made for the the generator. I found a couple of ideas here and here. But, there is no room on the Armstrong bracket for this, and I can't hang it off the side, as the supports would interfere with docking.
So it remains a quandary.
---
mike
Mike, why don't you go run the boat for while and see if you even need the darn thing. On the East coast facilities are close and you probably won't be anchored out for days on end. If you are on your way to Alaska might be a different story.
On the the loop most people with small boats like the CD 25 and Tom Cat with generators use them if at all only rarely, and those who have a generator regret the decision to carry it.
Eric
On the the loop most people with small boats like the CD 25 and Tom Cat with generators use them if at all only rarely, and those who have a generator regret the decision to carry it.
Eric
Hi Eric. Thanks for the advice, but the only reason I want to install a generator is to power the air conditioning, not for anchoring out. So the question is not whether to have a generator, it is whether to have air conditioning.helm":1hmjt7na said:
It's not quite summer yet, and we were in the mid 90s here today. And we get a fair amount of rain here in the summer (well maybe not by Seattle standards). So when it hits the mid 90s after a few days of rain, it will be a darn hot, sticky day.
Now I know my fellow C-Brats in Florida and Texas will laugh about me complaining on what to them seems to be a lovely spring day.
---
mike
Mike:
You are working through the problem having decided that you want a 13,500 BTU roof top unit. That is your controlling factor, but it necessitates a larger, heavier generator, which is turning out to be impractical.
After looking at the generator options (just as you are doing), many of us decided that the Honda 2000 offers the best compromise between portability (weight) and output. We then made the generator the controlling factor and let the "cooling" decisions flow from that. And we came to different (and satisfactory) answers, depending on our specific situations and needs- Dr. Bob has a rooftop unit, Dr. John has a portable unit inside the cabin, and Dr. Al (that would be me) has a $100 window unit in the front hatch. This is beginning to sound like a medical convention! :shock:
A smaller A/C unit combined with fans to keep the air moving in the cabin seems to be a better compromise than a larger A/C unit with all its attendant complications. I use a 120 v Lasko high-performance carpet-drying fan; others use multiple smaller 12-volt DC fans. BTW, to attain any kind of comfortable cabin temperature on a 90+ degree summer day, you are going to have shade most of the windows.
I agree with Eric. Use the boat, then decide what you need, and then decide on the compromise. There WILL be a compromise
You are working through the problem having decided that you want a 13,500 BTU roof top unit. That is your controlling factor, but it necessitates a larger, heavier generator, which is turning out to be impractical.
After looking at the generator options (just as you are doing), many of us decided that the Honda 2000 offers the best compromise between portability (weight) and output. We then made the generator the controlling factor and let the "cooling" decisions flow from that. And we came to different (and satisfactory) answers, depending on our specific situations and needs- Dr. Bob has a rooftop unit, Dr. John has a portable unit inside the cabin, and Dr. Al (that would be me) has a $100 window unit in the front hatch. This is beginning to sound like a medical convention! :shock:
A smaller A/C unit combined with fans to keep the air moving in the cabin seems to be a better compromise than a larger A/C unit with all its attendant complications. I use a 120 v Lasko high-performance carpet-drying fan; others use multiple smaller 12-volt DC fans. BTW, to attain any kind of comfortable cabin temperature on a 90+ degree summer day, you are going to have shade most of the windows.
I agree with Eric. Use the boat, then decide what you need, and then decide on the compromise. There WILL be a compromise
Hi Alok. Thanks, I really do appreciate the advice.Alok":3b3zkbf9 said:
But going with the 2000 instead of the 2400 wouldn't solve the problem, because I have no interest in hauling around a 50lb generator either.
In either case I would still want to mount it somewhere. And, I'm not quite ready to give on that yet.Who knows. In the end I may have to give up on it. But it the mean time, it sure is fun pondering various solutions to the challenge. Well at least it is to me.
---
mike
Mike:
I totally understand the fun of exploring the possibilities.
Just for kicks, if you have not already seen this thread from 2006, check it out. It will make you smile. We even had a simultaneous "generator" thread going, just like now.
http://www.c-brats.com/viewtopic.php?t= ... ng&start=0
Good luck in your explorations!
I totally understand the fun of exploring the possibilities.
Just for kicks, if you have not already seen this thread from 2006, check it out. It will make you smile. We even had a simultaneous "generator" thread going, just like now.
http://www.c-brats.com/viewtopic.php?t= ... ng&start=0
Good luck in your explorations!
Mike,
You know, in the beginning, I liked the numbers of the Yamaha units, but the size, weight and shape did not fit into any scenairos I could build myself.
Portable A/C units are specially designed to have low amperage draw starting compressors. This reduces the size of the genset you need.
I am now using an 11,000 BtU A/C unit that will start with a Honda i2000 generator running in Economy mode. That is around a 9 amp starting draw.
I don't think you'll find many rooftop units operating at that low a starting draw. yes, they do make special rooftop units like that, but they are heavier, need special mods to your boat, special wiring, etc.
As far as getting on and off the boat from the transom, I have had no problem with that be it while camping on the hard in transit or anchored in the water. The genset box is not as high as the transom and you have to get your legs over the transom, so there is no greater effort involved than if there were no genset box. In fact, it is easier in rough seas since you just sit down on the genset box and rotate your feet over into the cockpit with no need for delicate balancing.
I like the genset so I can run cooking appliances, TVs, charge computers, etc., not just for A/C. It relieves me of having a huge Inverter setup with heavy extra batteries to maintain, yet I always have backup power. The Honda i2000 has a built in charger system with an outlet and battery charger cord set.
In any case, the genset box only needs 4 bolts to remove or install - no holes, no fiberglassing, no external wiring. You just plug your 30 amp shore cord into the genset socket. The generator simply sits in the box with no screws/bolts, so all you have to do is lift it in or out of the box. The box has a lock so theft of the generator is minimal risk and you can put other gear in there if the generator is not in there.
The Honda i2000 sucks cold air in the front and blows hot air out the back along with the exhaust, so putting that hot air exhaust out the big flap is safe and leaves a cool, well vented casing for the generator. I am at 3 years of use now and have had no untoward experiences with this setup.
The A/C unit I use now is not the one pictured in Tom a Hawk's album, but it is held in place with ONE rubber shock cord, can easily be moved on it's built in wheels, and can be moved and mounted in 3 or 4 different places inside the TomCat cabin.
So you have more options with fewer needed modifications and NO irreversible changes in your boat.
John
You know, in the beginning, I liked the numbers of the Yamaha units, but the size, weight and shape did not fit into any scenairos I could build myself.
Portable A/C units are specially designed to have low amperage draw starting compressors. This reduces the size of the genset you need.
I am now using an 11,000 BtU A/C unit that will start with a Honda i2000 generator running in Economy mode. That is around a 9 amp starting draw.
I don't think you'll find many rooftop units operating at that low a starting draw. yes, they do make special rooftop units like that, but they are heavier, need special mods to your boat, special wiring, etc.
As far as getting on and off the boat from the transom, I have had no problem with that be it while camping on the hard in transit or anchored in the water. The genset box is not as high as the transom and you have to get your legs over the transom, so there is no greater effort involved than if there were no genset box. In fact, it is easier in rough seas since you just sit down on the genset box and rotate your feet over into the cockpit with no need for delicate balancing.
I like the genset so I can run cooking appliances, TVs, charge computers, etc., not just for A/C. It relieves me of having a huge Inverter setup with heavy extra batteries to maintain, yet I always have backup power. The Honda i2000 has a built in charger system with an outlet and battery charger cord set.
In any case, the genset box only needs 4 bolts to remove or install - no holes, no fiberglassing, no external wiring. You just plug your 30 amp shore cord into the genset socket. The generator simply sits in the box with no screws/bolts, so all you have to do is lift it in or out of the box. The box has a lock so theft of the generator is minimal risk and you can put other gear in there if the generator is not in there.
The Honda i2000 sucks cold air in the front and blows hot air out the back along with the exhaust, so putting that hot air exhaust out the big flap is safe and leaves a cool, well vented casing for the generator. I am at 3 years of use now and have had no untoward experiences with this setup.
The A/C unit I use now is not the one pictured in Tom a Hawk's album, but it is held in place with ONE rubber shock cord, can easily be moved on it's built in wheels, and can be moved and mounted in 3 or 4 different places inside the TomCat cabin.
So you have more options with fewer needed modifications and NO irreversible changes in your boat.
John
Warren,
I have the Permatrims on the Hondas so can get up on the swim platform without any ladder, so I do not usually have the ladder in place. If we are doing a lot of going on and off the boat, I put the ladder upside down in the brackets with a safety lanyard and a shock cord to hold it in place. You can see this in the first few photos of my Seattle trip album in Tom-a-Hawk's album. Due to my livewell tank, the fuel filters are on the outside of the stern so I have never been able to snap it in place there on the transom.
When down in the water, it has a tendency to float up and out of the bracket, so I wedge a rubber strip on a lanyard into the bracket to hold it down.
The ladder is usually stored up at the front of the forward bunk when not anticipating it's use. I can shock cord it to the aft rail if we are stopping and starting water activities on a frequent basis.
It is nice when one falls in the water, to have the Permatrims to sit or stand or kneel upon to aid in re boarding. If too tired, one can just reach the tilt switch and it will elevate you up and onto the swim platform.
John
I have the Permatrims on the Hondas so can get up on the swim platform without any ladder, so I do not usually have the ladder in place. If we are doing a lot of going on and off the boat, I put the ladder upside down in the brackets with a safety lanyard and a shock cord to hold it in place. You can see this in the first few photos of my Seattle trip album in Tom-a-Hawk's album. Due to my livewell tank, the fuel filters are on the outside of the stern so I have never been able to snap it in place there on the transom.
When down in the water, it has a tendency to float up and out of the bracket, so I wedge a rubber strip on a lanyard into the bracket to hold it down.
The ladder is usually stored up at the front of the forward bunk when not anticipating it's use. I can shock cord it to the aft rail if we are stopping and starting water activities on a frequent basis.
It is nice when one falls in the water, to have the Permatrims to sit or stand or kneel upon to aid in re boarding. If too tired, one can just reach the tilt switch and it will elevate you up and onto the swim platform.
John
I do like the way you mounted your generator. In the end I'll probably do something similar.drjohn71a":hbybraoy said:
That's a good point. I really have not been thinking about the other advantages on having the generator.drjohn71a":hbybraoy said:
On the air conditioner itself, if I didn't have so many hands aboard, I would definitely consider a portable unit.
I wish the pilothouse was longer and the cockpit shorter.
---
mike
Captains Cat
New member
Mike...":mfqfvj5d said:I wish the pilothouse was longer and the cockpit shorter.
---
mike
And in good weather, you'll wish for the opposite. Can't have it both ways!! :thup
Charlie