Fuel System
Of course, an engine needs fuel, and most engine failures are actually fuel system failures.
The fuel system on Island Eagle when we acquired her was a hodge-podge of different valves, pipes, tubes and filters, with no diagrams at all. After a few weeks of study, we understood it fairly well, and we determined that it would not meet our needs (big surprise!). After completing the interior renovation we turned our attention to bringing the entire fuel system up to snuff.
Step One - The Tanks
The tanks on Island Eagle are typical for boats of her age: two tanks of welded 1/4" steel, well-mounted against the hull and stringers. At roughly 1000 gallons each, replacing them is not really something that you want to contemplate. The good news is that they are both equipped with good-sized manholes, allowing them to be thoroughly cleaned. Thankfully, the interiors of the tanks were in fairly good condition, with only a few gallons of dirt and rust at the bottom. No signs of algae were found. We did find one place where there was some fairly deep pitting, and we had the welders do a bit of surface cladding in that area (yes, they were welding the inside of a fuel tank, in a wooden boat, in the engine room... my hair is even greyer).
The other change we made was to relocate the fuel pickup. It had been located at the extreme aft end of the tank, and 1 inch above the bottom. We were concerned that this would lead to the engine ingesting contaminants, and so we relocate the main fuel pickup several feet forward of the aft end and about 4 inches off the floor of the tank. While the welders were in, we had them make this change, as well as adding new fittings for sight gauges and new fuel return fittings. We left the old bottom outlets in place to use for the fuel polishing system.
At the end of the day the tanks were clean, dry ready for another 40 years of use.
Step Two - Designing The New Fuel System
Now, you know, there are thousands and thousands of boats out there. And they all need fuel systems. And the fuel systems have to follow some pretty strict regulations from the Coast Guard and it's recommended that they adhere to even stricter recommendations from the AYBC. So designing a fuel system should not be all that hard, right? Wrong!
I started the fuel system design process with a few ideas that I thought were pretty good, including:
1) Ability to draw and return fuel to either tank.
2) Ability to transfer from tank to tank.
3) Ability to polish fuel (draw and return to same tank through filters), using a separate filter bank.
4) Filters mounted at eye-level for good visibility.
5) A fuel pump pushing fuel through the filters.
With these goals in mind I drew up a plan and ran it by a few folks whose opinion I trust. Dieter the Electrician showed them to his colleague, the engineer on a 200 foot high-speed ferry. Our friend George, the local Transport Canada inspector, offered his opinion. And Ron Sparks, a frequent contributor on www.boatdiesel.com, also had a look at the plans. The result? I was roundly criticized. They made some excellent points, though:
1) You should always return fuel to the same tank you draw from. It reduces contamination, and prevents overflows.
2) Filters should always mounted as low as possible, so they will gravity-fill in a pinch.
3) Filters should always be mounted in the suction lines.
4) A full-time fuel pump was not required.
Finally, my initial design had a lot of flexibility, but that came at the cost of complexity. The KISS principal was quoted. Also, there were a few other excellent suggestions, including:
1) The ability to gravity transfer fuel between tanks.
2) The ability to drain fuel from the lowest point in each tank.
3) The ability to use the transfer pump to prime the fuel filters.
After checking with the experts, this was approved.
Step Three - The Components
The next step was to decide on the actual components to use. The tanks were already there, so that was no problem. We already had a set of Racor 1000-series filters which had originally been on the engine and that we would use as the transfer/polishing filters. We acquired a set of dual Racor 1000 MAX filters. These have a built-in valve that allows you to change a filter while underway:
Next came the problem of the pump. Many folks choose either impeller or vane pumps for this application, and these pumps typically will do about 12 to 15 litres per hour. But in our case, with roughly 4000 litres per tank, the pumps would burn out before the fuel was transferred or polished. We decided to go with a Groco CP-20 centrifugal pump, which has a high flow rate and is rated for continuous operation. The only downside is that it will not self-prime, and therefore you must mount the pump below the tank outlet. In our case, that was no problem, as we planned on mounting the pump below the floorboards.
The final decision was regarding what hoses to use. The original fuel hoses on the boat were 3/8" soft copper with flare fittings. Now, I grew up making flare fittings for diesel furnaces, and I hate flare fittings! They leak, they are inflexible, the copper pipe kinks, and to top it of the copper is not fireproof. So that was out.
The other popular solution is to use marine fuel hose (e.g. Trident), barbed hose ends, and hose clamps. I hate hose clamps! They're ugly, they rust, and they catch your fingers and cloths. Plus, once a fuel hose has been clamped up for a few years, you can never get it off the barbed fitting. So that was out.
My initial idea was to use hydraulic hoses with crimp-on connections. Hydraulic hose is tough as nails, inexpensive (about $2 per foot in the size I needed), and (if you have access to a crimping machine) easy to work with. They terminate on JIC fittings, which are like flare fitting but way better; they are the standard hydraulic fittings for industrial use and withstand about 5000 PSI no problem. I visited my friendly Parker store and priced out the options, and it looked good. The hose was excellent, and he assured me that it came off the same line as the marine hose. While I was there, the tech showed me their field-attachable fittings, and these were really cool: With just a vise and a wrench, you could put on a hydraulic fitting that was a strong as a crimp-on, without needing a crimper! Now we were cooking. I started making a list of the parts I'd need and got ready to buy.
But... just before I bought, I happened to mention my plans to my friend the big-ship engineer. Uh oh. "Sure" he said "I know lots of fishing boats that use hydraulic hose for fuel. And it works. But if you ever have a fire, your insurance will be void. And you can never have your boat Coast Guard inspected". What? Well, I looked into it and he was right. Hoses for boat fuel systems must be clearly marked as Coast Guard approved, and hydraulic hose was clearly not. The good news, though, was that Parker made just the hose I needed: Parker 221FR marine fuel hose.
When we filled the tanks for the first time, we first balanced the boat and then filled them 250 litres at a time, marking the sight gauges with zip-ties.
Rounding out the system are smaller Racor filters for the genset and heater. There is also a bleed line off of the polish/transfer pump so you can pre-fill the engine filters.
Bottom line: Every single inch of the fuel system in Island Eagle was new in 2005 and is built properly.
The fuel system on Island Eagle when we acquired her was a hodge-podge of different valves, pipes, tubes and filters, with no diagrams at all. After a few weeks of study, we understood it fairly well, and we determined that it would not meet our needs (big surprise!). After completing the interior renovation we turned our attention to bringing the entire fuel system up to snuff.
Step One - The Tanks
The tanks on Island Eagle are typical for boats of her age: two tanks of welded 1/4" steel, well-mounted against the hull and stringers. At roughly 1000 gallons each, replacing them is not really something that you want to contemplate. The good news is that they are both equipped with good-sized manholes, allowing them to be thoroughly cleaned. Thankfully, the interiors of the tanks were in fairly good condition, with only a few gallons of dirt and rust at the bottom. No signs of algae were found. We did find one place where there was some fairly deep pitting, and we had the welders do a bit of surface cladding in that area (yes, they were welding the inside of a fuel tank, in a wooden boat, in the engine room... my hair is even greyer).
The other change we made was to relocate the fuel pickup. It had been located at the extreme aft end of the tank, and 1 inch above the bottom. We were concerned that this would lead to the engine ingesting contaminants, and so we relocate the main fuel pickup several feet forward of the aft end and about 4 inches off the floor of the tank. While the welders were in, we had them make this change, as well as adding new fittings for sight gauges and new fuel return fittings. We left the old bottom outlets in place to use for the fuel polishing system.
At the end of the day the tanks were clean, dry ready for another 40 years of use.
Step Two - Designing The New Fuel System
Now, you know, there are thousands and thousands of boats out there. And they all need fuel systems. And the fuel systems have to follow some pretty strict regulations from the Coast Guard and it's recommended that they adhere to even stricter recommendations from the AYBC. So designing a fuel system should not be all that hard, right? Wrong!
I started the fuel system design process with a few ideas that I thought were pretty good, including:
1) Ability to draw and return fuel to either tank.
2) Ability to transfer from tank to tank.
3) Ability to polish fuel (draw and return to same tank through filters), using a separate filter bank.
4) Filters mounted at eye-level for good visibility.
5) A fuel pump pushing fuel through the filters.
With these goals in mind I drew up a plan and ran it by a few folks whose opinion I trust. Dieter the Electrician showed them to his colleague, the engineer on a 200 foot high-speed ferry. Our friend George, the local Transport Canada inspector, offered his opinion. And Ron Sparks, a frequent contributor on www.boatdiesel.com, also had a look at the plans. The result? I was roundly criticized. They made some excellent points, though:
1) You should always return fuel to the same tank you draw from. It reduces contamination, and prevents overflows.
2) Filters should always mounted as low as possible, so they will gravity-fill in a pinch.
3) Filters should always be mounted in the suction lines.
4) A full-time fuel pump was not required.
Finally, my initial design had a lot of flexibility, but that came at the cost of complexity. The KISS principal was quoted. Also, there were a few other excellent suggestions, including:
1) The ability to gravity transfer fuel between tanks.
2) The ability to drain fuel from the lowest point in each tank.
3) The ability to use the transfer pump to prime the fuel filters.
After checking with the experts, this was approved.
Step Three - The Components
The next step was to decide on the actual components to use. The tanks were already there, so that was no problem. We already had a set of Racor 1000-series filters which had originally been on the engine and that we would use as the transfer/polishing filters. We acquired a set of dual Racor 1000 MAX filters. These have a built-in valve that allows you to change a filter while underway:
Next came the problem of the pump. Many folks choose either impeller or vane pumps for this application, and these pumps typically will do about 12 to 15 litres per hour. But in our case, with roughly 4000 litres per tank, the pumps would burn out before the fuel was transferred or polished. We decided to go with a Groco CP-20 centrifugal pump, which has a high flow rate and is rated for continuous operation. The only downside is that it will not self-prime, and therefore you must mount the pump below the tank outlet. In our case, that was no problem, as we planned on mounting the pump below the floorboards.
The final decision was regarding what hoses to use. The original fuel hoses on the boat were 3/8" soft copper with flare fittings. Now, I grew up making flare fittings for diesel furnaces, and I hate flare fittings! They leak, they are inflexible, the copper pipe kinks, and to top it of the copper is not fireproof. So that was out.
The other popular solution is to use marine fuel hose (e.g. Trident), barbed hose ends, and hose clamps. I hate hose clamps! They're ugly, they rust, and they catch your fingers and cloths. Plus, once a fuel hose has been clamped up for a few years, you can never get it off the barbed fitting. So that was out.
My initial idea was to use hydraulic hoses with crimp-on connections. Hydraulic hose is tough as nails, inexpensive (about $2 per foot in the size I needed), and (if you have access to a crimping machine) easy to work with. They terminate on JIC fittings, which are like flare fitting but way better; they are the standard hydraulic fittings for industrial use and withstand about 5000 PSI no problem. I visited my friendly Parker store and priced out the options, and it looked good. The hose was excellent, and he assured me that it came off the same line as the marine hose. While I was there, the tech showed me their field-attachable fittings, and these were really cool: With just a vise and a wrench, you could put on a hydraulic fitting that was a strong as a crimp-on, without needing a crimper! Now we were cooking. I started making a list of the parts I'd need and got ready to buy.
But... just before I bought, I happened to mention my plans to my friend the big-ship engineer. Uh oh. "Sure" he said "I know lots of fishing boats that use hydraulic hose for fuel. And it works. But if you ever have a fire, your insurance will be void. And you can never have your boat Coast Guard inspected". What? Well, I looked into it and he was right. Hoses for boat fuel systems must be clearly marked as Coast Guard approved, and hydraulic hose was clearly not. The good news, though, was that Parker made just the hose I needed: Parker 221FR marine fuel hose.
When we filled the tanks for the first time, we first balanced the boat and then filled them 250 litres at a time, marking the sight gauges with zip-ties.
Rounding out the system are smaller Racor filters for the genset and heater. There is also a bleed line off of the polish/transfer pump so you can pre-fill the engine filters.
Bottom line: Every single inch of the fuel system in Island Eagle was new in 2005 and is built properly.
