Fuel tanks

I have four fuel tanks on board of my trawler. Given this first sentence seems to sum things up I could be getting off easy in regard to this post and leave it at that. But since I'm a little on the long winded side of this world, and the fact that I'm totally into all things steel boats, I feel as if I should elaborate a little on my fuel tanks.

The four fuel tanks on board are integral tanks meaning they are now part of the hull. The tanks are on the outboard sides of the hull in the engine room between station 9 @ 14. I am using the term station as this is how the prints describe frame locations, and these two locations are actually steel bulkheads. I framed the tanks using 1/4" plate. All the tanks have a baffle located @ 30" on center witch is also what the frame spacing is. The baffles have the corners clipped off of them and also have 2" holes in the center to let fuel flow freely between them. The baffles are welded on all four sides of the tank walls and by using the slug welding method I was able to weld the baffle to the tank top. All four tanks have a drain valve at the lowest point in the tank in case I ever have to empty the tanks completely.

I could not in good conscience build these four tanks without providing a way to get back inside of them if I ever have to. I added an inspection port between each baffle for future maintenance. The inspection covers are made of 3/8 plate and are attached to the tank by a 3/8 stud that is welded to the inside of the tank wall. The inspection ports are 12" in diameter and are in the front wall of the tank. Because of the size of the tanks, putting the inspection ports on the top of the tanks made no sense as it would serve little use due to the depth of the tank. Getting the inspection covers to pass the air test proved to be the most difficult part of building these tanks. Using fuel rated gasket material I cut a gasket for each cover and punched holes for the studs. I then used a fuel rated gasket sealant applied to the gasket to improve the seal of the gasket. Because I did not want to stretch my mounting studs I used a torque wrench to tighten the nuts to the correct torque for a 3/8 bolt. My first air test showed each stud to leak! Next I tried using a heavy thread sealant on the studs. My next air test showed the studs to leak! The problem was the weld holding the stud to the tank was not air tight and my 7 psi air test was leaking past this weld and then past the mounting nut. My solution to making the covers air tight was to mill a counter sink in each tank cover to accept an "O" ring for each stud. I milled the counter sink in the covers to a precise depth so that the washer under the nut would compress the fuel rated "O" ring and provide a seal once the nuts were torqued down. My next air test proved all the studs passed the 7 psi test. I spent another day or so finding pinhole leaks in the tanks and making weld repairs. The final air test was to have the tanks hold 7 psi for 24 hours.

My two forward tanks ( port and starboard) hold 200 gallons each. The two aft tanks ( port and starboard) hold 500 gallons each. I intend to use one of the forward 200 gallon tanks for running the main engine and generator and the other three tanks will be used for storage. I'll have to transfer fuel from the various tanks via an electric fuel transfer pump. I'll probably use this same pump to polish my fuel from time to time to keep it clean and keep the condensation water out of the fuel. The total fuel capacity on board will be around 14oo gallons. This 1400 gallons is more than what the boat was designed for so I contacted the architect who designed the boat and reviewed this with him. Hal Wittacre ( the naval architect) did some stability calculations and recommended adding more ballast to the boat.

Each tank has a pick up tube for fuel supply and return. These pick up tubes go to within 1" of the tank bottoms. There is a fill point for both port and starboard on the aft deck of the boat. A two inch steel pipe will be used as the fill tube, with a vent that leads back to the fill port. The fill ports on the tanks just dump into the the top of the tank but I want to change that and add a tube that goes to the tank bottom. Bringing the fill tube to the tank bottom is a better design element for fuel tanks and I will make this change.

The fuel management system is fairly complex and really needs it's own post to get into the details. Once I start work on this part of the fuel system I'll add a fuel management post.

The tanks are shown in these pictures with a plywood cover. I did this so that I could protect them during construction. Plywood will also be the final cover as there are many things that will be attached to this plywood.

Conall

Rudder and Steering

The rudder on my trawler is a rather large device. The approximate dimensions are 2.5' wide by almost 5' tall. Having installed the rudder a few times I'm going to guess it's weight at 200+ lbs. The rudder looks more like a wing and is constructed in such a way as to have two skins wrapped around the wing shaped frames. It is very sleek looking and more reminds me of a sailboat rudder vs a rudder you would see on a work boat. Compared to the rudders I see on house boats around my home port, this rudder has a tremendous amount of square footage to aid the steering of the boat. By looking at the rudder alone, I would guess this boat will be very responsive to the steering wheel. Becuase of the way the rudder is fabricated it is impossible to paint the inside to protect the steel. Because of this type of rudder construction I air tested the rudder to 10 psi to insure that no oxygen gets inside of the rudder and speeds up rust corrosion.

The rudder is connected to the boat via a large skeg or shoe that is an integral part of the keel. The rudder has 2" stainless stock welded to itself that is flanged on both the top and bottom of the stock. The bottom flange bolts to another flanged piece of 2" stock that sits in a bearing in the skeg. The top flange bolts to piece of 2" flanged stock that passes through a bearing that goes up into the lazzarette of the boat ( rear room) and connects to the steering gear. The flanges for the rudder system I fabricated out of 3/4" stainless stock and bored them to accept 5/8 bolts to hold them together. I'll have to design some sort of locking ring to retain the nuts or use a castle type nut with a key to hold the nuts fast. The bearings for the rudder in the skeg and where the rudder stock enters the boat @ the lower end of the rudder log ( rudder tube) are made from a material called Vesconite. Vesconite is designed just for this application and is claimed to be top of the line material for what I'm trying to do with it. I will not have any galvanic worries with this type of rudder bearings.The rudder tube terminates inside of the boat about 8" above the water line. I added another bearing at this point of termination for a total of three rudder bearings. With the rudder installed I'm able to move it with just a little pressure from my finger tips. I'm totally happy with the bearings and the rudder alignment. Because of the mix of a stainless steel rudder shaft and mild steel boat I will add a zinc or magnesium annode to the rudder to slow down any galvanic corrosion.

The actuall steering system on the trawler will be what most would consider a power steering system. My main engine has a port on it to accept a pump that will power the steering helms that in turn will power the hydraulic rams connected to the rudder shaft. I will have two helms on my boat; one helm in the wheel house, and another helm on the roof as a fly bridge. In case of a catastrophic failure of the steering system, I have an emergency tiller device in place to steer with ( see my earlier post " emergency tiller"). The hydraulic rams are more a heavy duty set up I purchased from Hydro Slave Co. The steering gear consists of a heavy cast bronze quadrant, two hydraulic rams, and an integral arm to limit travel of the rams. If you look at the first picture posted you will notice my attempt at rudder stops welded to the hull. I know they look a bit odd, but at least I made some attempt at aero dynamics and they also wont increase any corrosion issues. The quadrant connects to the rudder shaft via a heavy clamp and a 1/2" stainless key way and key. I went with this type of dual ram set up becuase it causes zero side load on the rudder shaft. I am totally pleased with this piece of equipment, and while it was pricey, I feel it was money well spent. I'll be adding to this blog once the steering system is fully connected and operational with the helm pumps in place along with the hydraulic lines.

Conall

Bash Bars

The first time I heard "Bash Bars" was the last time I called steel round bars used to cover frames edges "steel round bars used to cover frame edges".

From what I know of the origin of this description is that it came from a guy I know in Australia who is building a steel sailboat. His name is Martin ( Idlerboat is his web name) and he is one of the founders of Metalboatbuilding.org . So from this time forward I use "bash bar" .

A bash bar is built by welding round stock to a frame edge to protect that frame edge. It is much easier to get paint to stick to a 1/2 round bar vs the ground edge of a frame. When that frame gets banged into and paint chips, the stainless steel round bar will be exposed and will not rust so touch up and repair will be a breeze without the unsightly rust stain in these high wear areas. All the frames on the exterior of the boat that will not be covered up and that are subject to getting banged get treated with this bash bar. I used 1/2" stainless for my bash bars. On the foredeck of the boat I bash protected the frames, the bulwark cap edge, freeing ports, the door frame and the toe kick areas of the door. On the Portuguese bridge I treated the frames only as the cap for the Portuguese bridge will be covered with teak. On the cockpit area or aft deck, I treated the frames, door, freeing ports, and left the bulwark cap untreated as this too will be covered with teak.

On the freeing ports and hawse holes I held the bash bar flush to the outside hull sheathing. This gives the hull a great finished look, and I also like the look on the inside of the hull too. While the bash bars are held proud on the inside of the hull sheathing, it gives the hull a more finished look albeit a utilitarian look, and I like the utilitarian look for a steel hull. I've used some effort to fair the hull and hide the welds. I don't know if this was a mistake or not as I think a good looking weld is something that does not need to be covered up. A lot of people will tell you not to fair the hull and let the welds stand proud, and with the money saved both in fairing and repairing dings, I can't say I don't dissagree with the no fairing method. Almost all commercial boats use no fairing, and I love the look of a commerical boat.

Conall

Water Tanks

My current boat ( 28' Carver Mariner) has a whopping 25 gallon water tank and I'm amazed at how long we can make that 25 gallons last. On the current boat we use water primarily for washing dishes and an occasional quick shower. The head on the Carver is raw water flushed so we don't tap into that precious 25 gallon supply.

The water tanks on the trawler ( I guess I'm going to have to name her soon so I stop calling her the " trawler ") are constructed out of stainless steel. I went with stainless steel vs plastic for a few reasons. Stainless is considered top of the line in regard to potable water tanks. Due to where I'm placing the tanks it made more sense for me to fabricate the tanks vs having them fabricated out of plastic. I used 14 gauge 316L for fabricating the tanks. All the associated fittings for the tanks are 3/4 NPT stainless ( fill, vent, supply) couplers welded in place. All the tanks have one center baffle running across the width of the tank. The tanks fit between the frames of the forward area so the tanks have to fit into a 30" wide space. Because of the 2" flange I welded on to the frames I had to make the tanks 27" in width to give me a little room for the install. I might be kicking myself in the ass years down the road, but I decided to not install inspection covers in the tanks. I have a total of 8 tanks giving me approximately 350 gallons of water.

The tanks are held in place with a flange welded on to the front and back of each tank. The forward mounting system consists of a bracket welded to the hull with 3/8 studs welded to that bracket. The forward tank flange fits over those 4 studs and is bolted down. The rear mounting system consists of a similar bracket only I welded nuts to that bracket and used four 3/8 bolts through the tank flange to mount the rear part of each tank. I used studs on the forward mounting system because the bracket is so deep it was easier to get a nut started vs getting a bolt started. It was also easier installing the tank by dropping the tank over the studs then having a little wiggle room to get the bolts started in rear of the tank. For 3/8 studs and bolts I drilled the corresponding mounting flange to 1/2 " and used thick washers for the mount. I made a gasket out of flexible PVC to help isolate the tank bottom from the mounting brackets ( no metal to metal contact other than the mounting hardware). I allowed myself 4" of clearance between the front of the tank and the center longitudinal frame ( center spine). 4" of clearance was barely enough room, as it is a tight fit to get my arm in there. All the tank mounting hardware is stainless steel

To supply water to the pump I welded a 3/4 stainless coupler in the the bottom of each tank. Having given this a little more thought I now wish I had used a pick up tube entering the top of the tank and going to the bottom. Too late for the pick up tube method now, but again I wish I had gone that route. So each tank has a coupler welded in for supply, followed by a gate valve for each tank,followed by a "T" for each tank, all of this terminates into a common supply line leading to the pump. I went with this set up so I could isolate each tank vs all eight tanks having a shared liquid level. If I ever have a catastrophic failure of a tank, I can take that tank off line and not loose all my water. I also have the choice of just filling a couple of tanks if I want. Since I am able to isolate the supply side of the tanks, I also have to be able to isolate the vent side of the tanks. All the vents will terminate at a manifold that can be valved before venting at the wheel house deck above the fill point. The tanks will fill from two points on the wheel house deck via port or starboard fill pipes. Because of the large cabin and wheel house roof areas I'm making provisions to be able catch water off the roof to fill the tanks.

I air tested each tank to 6 psi as this will be more than the static head the tanks will see once the vent tube fills to the deck level. After I fabricated the tanks I installed them to check fit and make sure all my brackets would work so I could start the interior painting. If I had been a little more careful with my measuring and fabricating I could have squeezed another 50 gallons of storage in my system, but all in all I'm happy with 350 gallons.

Fairing the hull

The phrase "fairing the hull" took me a while to figure out it's origin. My interpretation of what is fair is just that... it feels fair. Running ones hand across the hull sheathing reveals more than what your eyes can see and as you keep running your hand across that hull skin you start to get a feel for what's fair. Fair is not perfect and fair is not feeling bumps and gouges in the metal... fair is fair...it feels pretty fair. Sort of like how Manana does not mean tomorrow, it just means not today.

I bought my steel wheel abraded, primed and plasma cut. The wheel abrading removed the mill scale and left a good profile for the primer to stick to. I'm building inside so rust has been a non issue for me and my original primer has remained intact. I started the fairing process ( above the water line only) by grinding all welds smooth. I also hit some of the "weld through" with a grinder if the bumps felt abnormally high. Weld through are areas where the metal pushed out from the welds I created welding the longitudinal stringers to the hull sheathing. After I had all the grinding done I spot sand blasted all the grind marks, rub rails, and any spot that had rust blooming. I then gave the whole hull a light blasting to tooth up the existing primer. I blew off the hull with compressed air and applied three coats of epoxy primer alternating colors between the coats ( white and gray). I then began the process of mixing epoxy ( Gougon Brothers) fairing compound and filled all the areas I had ground such as weld seams and deep weld through marks. After multiple applications and sanding of those areas I sprayed one more coat of epoxy primer then gave the hull two coats of high build primer with the tendency to lay it on thick.

High build primer is like liquid filler putty being extremely easy for one to sand. Using a 30" flexible sanding block and rolls of self adhesive 80 grit 2" wide sand paper I sanded the hull. The high build primer shows every little dip and doodle in the hull. While "long boarding" the hull I'd find areas where I'd sand back into the metal ( very high spots). If these areas were really high I'd hit it with a the grinder, re blast, re prime with epoxy, more filler if needed, more high build, re sand. I really did not use much filler as the hull was very fair when I began. Most of the filler was used up creating a smooth transition from the hull skin to the rub rails, around the port lights, and in the area of the freeing ports and hawse holes. Once I was pleased with the long board sanding I blew off the hull, vacuumed the hull, wiped her down with tack rags and applied two more coats of epoxy primer to seal the high build primer.

I faired the hull one side at a time, working at a pretty steady rate since I was doing this over the winter in the shop. Each side took two months to complete and has landed on the top ten most nasty jobs to date.

Having now looked up at the hull thousands of times in varying light I have found a few areas that will need more a little more fairing before I apply the topcoat. I'd guess I'll have two more days in fixing some of these areas so I don't consider them a big deal as most will just involve some sanding and high build primer. My future plan for the top coat is to scuff the few areas that need attention, epoxy prime, high build, sand and repair, more epoxy primer. The whole hull will get a good washing, a scuff with 80 grit, one more coat of epoxy primer, then I'll spray the top coat.

I only have a few pics of the faired hull. For the most part all the body work is finished and she's ready to paint. I'll be able to topcoat a few areas of the hull in the shop prior to attaching the wheel house and salon, but I'll probably save the bulk of the hull topcoat until after the wheel house and salon are attached.

Conall

Cleats

All of the cleats for the boat were fabricated by yours truly in "Conallville" ( that's what my brother calls my barn).The cleats are made from 1.25" 316 stainless round stock of the L variety. I copied the style of cleat that I see on all of the boats in this area and this style seems to be the best fit for me in regard to where I'm positioning the cleats on the boat. I purchased a 3/4" rounding over bit for my lathe witch does a fantastic job of giving me a perfect radius on the edge of the cleat ( vs the homemade done on the grinder look). The round over bit cost about $40.00 witch I consider a small price for quality, and there will be many other jobs I'll be able to use it on as I do some more finishing type work. Hopefully, folks who know what they are looking at will appreciate the details as I do. I used the lathe to cut all the bevels on the round stock for maximum weld penetration by the MIG. All the parts were pickled, passivated, then re polished once installed. All the cleats are welded in place and while I don't foresee them being torn off, I still think I'll make a few spares cleats to throw in the on board parts warehouse.

I have two aft cleats, two spring line cleats ( mid ship), and four cleats on the bow. I added two more cleats on the pulpit to get the total of four bow cleats just because I had the space and I figured it would also help with the anchors. The two stern cleats, and two of the bow cleats are welded up high off of the deck so that the lines pass through hawse holes I fabricated myself. I used 1" round stainless stock and bent it in an oval shape then welded it to the hull. I also added a doubler plate in this area of the hull to spread out some of the point loads the hull sheathing might see from the 1.25" round stock. The mid ship spring line cleats were held as far out on the hull as I could. I welded this cleat directly to the center bulkhead of the boat also create another frame to move the load to the floor of the cabin vs the hull side sheathing. My experience on spring line cleats is they tend to take the brunt of the load of the boat and I don't want paint popping off the boat by having the hull sheathing flexing. My intent of holding the spring line cleat as close to the cap edge as I could was to minimize line chafe and prevent the spring lines from rubbing the paint off of the hull. After the weld up I was not satisfied that my lines and hull would be protected so I took a some 1" stainless pipe, plasma cut/ripped 1/3 of the pipe away, added some decorative pointy ends and welded it to the hull to act as a rubbing strake. The length of the rubbing strake is 3' and I'm pretty sure it will work just fine. I did create a small issue by adding the rubbing strake in the area of the strake between the cleat and the bow. Because of the height of the strake and the shape of the bulwark cap, I created a small ( 2 square inch) area for water to pond. I'll have to either drill a drain hole of some sorts or add epoxy fairing compund to raise the area and have the water shed overboard. This is a pretty minor deatail, and it is the only place on the boat I know of that will trap water.

I think I'm going to add a sampson type post on the pulpit right above the door because I think it will look good and will also help with the anchors. I also have a sampson type post on the swim platform for the sole purpose of tying off my dingy when she's not stored on the cabin roof.

Conall

Generator

I've purchased a 10kw, three cylinder, diesel powered generator for the boat. The generator will be cooled by sea water using a closed cooling system with a single pass cooler. The exhaust from the generator will be injected with this cooling water to lower the temperature, then that mix will be pumped overboard via piping and through a water lift muffler. The generator will reside in the engine room.

I think 10 kw is to big of a generator for this sized boat but I got such a good deal on it I had to make the purchase. I'm going to have a washer and dryer so the extra amperage will come in handy for powering the dryer as this device will by 230 volt ( unless I go with one of the expensive 120 volt "marine" dryers). The boat will have two air conditioner units and these units also tend to be large consumers of power.

I'm installing a hydraulic system for the boat and the person who has been giving me pointers on the system design ( that would be Jim at Key Power) has recommended I install a hydraulic powered generator along with my stand alone generator. I think this is a good idea and I'm planning on doing it. Since the main engine will be powering the hydraulic system, taking advantage of the relatively free power and not having to run the stand alone gen-set will lower fuel consumption. I also intend on installing an inverter to power the fridge and a few AC circuits while we're at anchor so we don't have to listen to the generator. The engine room is going to be heavily insulated so I'm debating if I should fabricate a sound shield for the generator. My thinking is that I'll probably install the sound shield to ensure a quiet boat. I intend to get into a little more detail on AC and DC power and how things are going to work on the boat, but for now I'm posting the basics.

Conall