compressor for sailing

[pescador775]

All that is true but does not address the questions posed here which have to do with cruising trips with dive excursions and have less to do with blue water sailing. I have sailed or bareboated 45 foot Fontaine catamarans throughout the West Indies. During those trips I carried on deck my homemade Kidde gas powered compressor and kit including spare gasoline. Also, the boat always carried a gas powered dinghy with extra tanks. During underway periods the compressor was alternately in service or placed in its carrying case and lashed down. The dinghy was in dive related use or lashed outboard in the usual way and gas was stored in deck compartments. No big deal. There are differnt types of saillboats and the big cat is very suitable for divers.

Sailboats are not dive boats. Your typical dive boat is what you might call a "run about" suitable for good weather trips for a couple hundred miles. A 65ft sail boat is capable of taking a trip through the Panama cannal and heading to New Zeland, pretty much non-stop and dealing with whatever the ocean does to it on the way. Even if the owner would never do such a trip almost all owners take the effort to maintain the boat such that it could. My guess is that the owner simply would not want a portable gas engine on deck.
The typical sailboat will have a cabin roof 18 or 20 inches above
the deck. Believe me, exaust and gas fumes will find a way into the space below.

First off, where to store it while it is not in use? No you can't keep it
on deck, Sailboat decks take tons of water while the boat is under way. (Sailors _like_ to go out in 20 knots wind and big waves.)
And sailboats, while being sailed (as opposed to motored) need the deckspace for the crew to work and for lines, poles, sailbags and
what have you to move around.
You'd need a cockpit locker with chocks and hold down straps installed. But on a sailboat locker space is very valuable.
a 60ft sail boat will have only 1/3rd the space of a 40 ft diveboat
as the cabin roof willbe 5 ft above the waterline with no decks above.
I'd bet the engine compartment would be the best place. and now you are into a permenent installation. Cruising sailboats that
have compressors almost always mount them perminently.

I'll bet the electric powered model is the one to get as a boat that
size would likely have a diesel genset

 

[Isaac-1]

This is just a quick note as I have driven about 1,300 miles today. I picked up the Purus, found out a little about its past (It was originaly owned by a volunteer fire department to fill SCBA tanks, was in active use until 1999, and sometime in those 20 years had one professional rebuild) One unusual thing I noticed is the manual list specs of max 1,600 RPM and the metal plate with the serial number etc. list 2,000 RPM. The scuba fill whip and gauge were added by the guy I bought the unit from, he aparently has very lightly used this unit over the last 5 years. More later when I am awake.

Ike

p.s. in the case of my sailboat, gasoline is the only option as the engine is a well mounted outboard

 

[pescador775]

No problem, I'll be around when needed. The RPM spec for the PURUS depends on the driver. The factory RPM for the '78 GAS engine driven PURUS is 2100. This must be taken into account when you purchase the 3.5 HP Briggs & Stratton engine. One must assume that, under load, the engine governor will drive the shaft at 3300 rpm. This is typical. Measure the size of the PURUS pulley and then calculate the size required for the engine pulley to spin the Bauer pump at 2100 rpm. This is a simple ratio of the two diameters. When positioning the engine place the engine in such a way as the pulleys precisely line up and the belt is straight. If the engine shaft is too long the Briggs shaft can be cut off. The following is how it is done. Install the pulley wheel in the correct position and make a mark on the shaft. Cut off the key to correct length, install and tighten the set screw. Run the engine at 1500 rpm and place a blade flat against the pulley at the mark. It will take only a couple minutes to cut off the soft nodular iron shaft to the correct length.

This is just a quick note as I have driven about 1,300 miles today. I picked up the Purus, found out a little about its past (It was originaly owned by a volunteer fire department to fill SCBA tanks, was in active use until 1999, and sometime in those 20 years had one professional rebuild) One unusual thing I noticed is the manual list specs of max 1,600 RPM and the metal plate with the serial number etc. list 2,000 RPM. The scuba fill whip and gauge were added by the guy I bought the unit from, he aparently has very lightly used this unit over the last 5 years. More later when I am awake.

Ike

p.s. in the case of my sailboat, gasoline is the only option as the engine is a well mounted outboard

 

[Isaac-1]

Ok here goes a bit of new information, I have the electric motor off the Purus now, and I have opened up the Filter assembly. Photos can be seen at www.beau.lib.la.us/~ikes/compressor there are smaller versions of the two new photos with the word "small" in the file name. As you can tell by the photos the old filter appears to be of the original design and does not appear to have been changed in a very long time. the threads on the filter were coroded and it took some work to remove it. I weighed the old filter and the new sealed in package one the old weighed in at 95 gm and the new at 70 gm on a postage scale. The felt filter material appears soaked with oil and discolored on the old filter. I suspect that the previous owner never changed the filter as I had to remove a number of plastic wire ties that were on the fill whip in order to get the filter out of the canister.

Ike

p.s. the compressor came with about half a gallon of oil (labeled as synthetic scuba compressor oil), an orignal manual, a heavy duty cover, a set of tools including a 2 size pin indexed spanner and assorted hex keys, a spare 5000 psi gauge, a new pre-filter and the new filter cartridge in the photo. I am not sure if I listed this earlier (I was rather tired when I posted my last message) I did find out that the compressor originaly belonged to a volunteer fire dept. and was sold to the guy I bought it from in 1999. At some point in time when the fire dept owned it the compressor was rebuilt although there is no visible sign of this.

 

[Isaac-1]

Here are a couple of quick things, how does this engine look to you? http://www.smallenginewarehouse.com/product.asp?PN=GC135QHA Its a honda, should fit in place fairly well, and unline the Briggs and Straton units it has a verticle cylinder and exhaust oposite the compressor. Also where can I find a proper size pulley for the motor, the compressor pulley is 3.5 inch external size, I assume the proper size would be between 2.25 - 2.5 inches.

thanks again Ike

 

[pescador775]

Isaac, the original engine for this assembly was a Briggs. The Honda will not work. The mounting points are the same as the Briggs but the reverse exhaust will burn up your pump unless you install a deflector of some sort. You are looking at the problem through a mirror. The Honda will only work on a 'reverse' compressor in which the pump is located behind the engine, not forward in the usual manner.

Here are a couple of quick things, how does this engine look to you? http://www.smallenginewarehouse.com/product.asp?PN=GC135QHA Its a honda, should fit in place fairly well, and unline the Briggs and Straton units it has a verticle cylinder and exhaust oposite the compressor. Also where can I find a proper size pulley for the motor, the compressor pulley is 3.5 inch external size, I assume the proper size would be between 2.25 - 2.5 inches.

thanks again Ike

 

[pescador775]

That is quite a piece of history. The filter cartridges are repackable. Do NOT discard. These are probably unavailable. They can be repacked with Vaporshell 13X and activated charcoal. However, judging from the condition of the original filter cartridge the mechanical separator section is probably a simple baffle which is very inefficient at low back pressure. This is all the more reason to check the setting of the BP valve. This can be done by running the compressor with the tank valve closed and simply noting the pressure at which the gauge shows a big jump. Otherwise, connect a tank to the valve with the original fill hose and note the pressure at which the valve releases air. It will be necessary to remove the valve to do this and an adapter will be needed (hydraulics shop?). Later versions of the Bauer filter canister used a micronic separator which is a sintered disc, somewhat like a large regulator filter disc. This design is more efficient as more surface area is presented to the incoming air. Nice photography. I'm curious as to how this is done; transferring the pictures to the web, etc. I'm not very computer smart.

Ok here goes a bit of new information, I have the electric motor off the Purus now, and I have opened up the Filter assembly. Photos can be seen at www.beau.lib.la.us/~ikes/compressor

 

[oxyhacker]

That filter is the little one indeed - there's supposedly a steel version (#04852?) made to be refillable, and it looks like you could refill the plastic one you got if you remove the wire clip carefully. And Lawrence Factor makes replacement disposable cartridges for it, expensive but useful if you just want to get it up and running. If you are a fearless do-it-yourselfer there are a few alternatives on our website, such as the infamous $35 surplus accumulator filter housing.

BTW, best I can recall, a lot of the Bauers in the 70's came in a 223 bar and a 330 bar version, the main difference being a higher pressure rated "double ended" filter housing like the one on your compressor. Pesky?

Re the motor the B&S is probably the easiest alternative but you could probably flip everything around and use the much better Honda, at the cost of redrilling some holes. Lot easier if you can borrow a Honda just to see if it will fit - I got two sitting in the barn but you probably don't need another road trip.

 

[pescador775]

Uh Oh, I took another look at the pics. That PURUS is a 'reverse' compressor. First I've seen. I guess Mako did their own thing when they assembled the system. That being so, the Honda GC type will work. Sorry about the mixup. Bauer lists that model as 3200 psi with 5000 psi models 'available'. I'm not sure what the difference is, probably a different relief valve.
Pesky

Isaac, the original engine for this assembly was a Briggs. The Honda will not work. The mounting points are the same as the Briggs but the reverse exhaust will burn up your pump unless you install a deflector of some sort. You are looking at the problem through a mirror. The Honda will only work on a 'reverse' compressor in which the pump is located behind the engine, not forward in the usual manner.

 

[pescador775]

The math is correct. GRAINGER's sells pulleys. They have a web site. For search purposes pulleys are sometimes called 'sheaves'.

Here are a couple of quick things, how does this engine look to you? http://www.smallenginewarehouse.com/product.asp?PN=GC135QHA Its a honda, should fit in place fairly well, and unline the Briggs and Straton units it has a verticle cylinder and exhaust oposite the compressor. Also where can I find a proper size pulley for the motor, the compressor pulley is 3.5 inch external size, I assume the proper size would be between 2.25 - 2.5 inches.

thanks again Ike