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[技术] 科纳尔的拖网渔船建造

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 楼主| 发表于 2015-6-27 22:46:08 | 显示全部楼层

拖网渔船建造

拖网渔船建造


拖网渔船建造

拖网渔船建造


拖网渔船建造

拖网渔船建造

For the type of boat I'm building I feel a good swim platform to be essential for getting on and off the boat while at a harbor or at anchor. I want a swim platform that will be able to take serious amounts of abuse and be basically bullet proof while being an easy to navigate tool of function. I decided upon building the swim platform out of stainless steel given my opinion that it will receive its fair share of dings. A wood platform, while attractive, I felt would one more maintenance and repair item for me a little further down the road.
Once I decided upon an elevation above the water line for the platform I began by taking my ripped sections of 4" sch. 40 and adding back in a notched section that would make up the longitudinal frame of the platform. After these were welded to the hull perfectly level with the drawn water line I began the task of bending the athwart ship section of the platform. The only part of the stern that could handle the force of bending the pipe ( I was using the stern as my pattern) is the area where the cockpit deck meets the transom. I welded some jigs on the starboard side of the hull to hold the pipe fast and on the port side I welded some cleats to use as pull points. Using a one ton chain hoist I bent the 4" pipe unit she would bend no more... pretty much the shape of the transom less a little spring back on the pipe. Since I'm not building a watch and only the most of anal observers would realize the shape of my bend was not an exact duplicate, I called the job a success. To make the transition from the longitudinal pipe to the athwart ship section, I used two 90's cut to the fairest line I could make work. I know I'll need a little fairing compound on this area, but all in all it looks pretty damn good. I added 3/16 x 2" frames to support the platforms 12 gauge deck.
The platform extends 24" away from the transom and while I'd prefer 30" I'm satisfied with this depth. This is now my only way on and off of the boat while I build her. After a few trips on to the boat with the new swim platform I soon realized that a better set up steps other than conventional boat ladders were in order, so I designed what I consider to be a good alternative. I welded the treads for the steps out of 3/16 stainless and used some left over 4" stainless pipe with some 45 degree fittings for the stringer. The odd shape of the tread was my way of marrying the winding of the path of the steps with the 4" pipe that supports the steps. Given the fact that the platform is some 10 above my concrete floor I added some "U" shaped safety rails fabricated from 1.5" sch. 40 stainless along with a safety rail to help one navigate the steps. All the vertical pipes were fitted to the 4" section by clamping them in my mill and using a 4" hole saw to cut the profile for an exact fit to the 4". A boarding ladder will pin to the port side safety rail and on the outboard side of the rail. I added a bit under the middle safety rail and while I now think the proportion of the bit is a little off, I have yet to decide if I should make it shorter ( the bit is 2" sch. 40 with a solid bar of 1" welded through). Besides keeping me safe from falling and smacking the concrete I really feel the rails and the steps will make boarding the boat very safe and easy for even the drunkest of guests.

 楼主| 发表于 2015-6-27 22:47:44 | 显示全部楼层
Bowsprit and forward handrails

拖网渔船建造

拖网渔船建造

In regard to handling the anchor and related gear I've always thought a bowsprit or pulpit would be a safety item for all who have to work on the bow. I wanted my anchor to be far enough away from the hull so that the anchor might not bang into the hull as it is deployed or retrieved. I also wanted the bowsprit to be stout enough to handle all forces put upon it by a rough anchorage. I'm thinking I probably went a little overboard in constructing the pulpit, but since I'm new at this boat building thing I'm giving myself a little bit of leeway.
I figured that the pulpit would be an area of the boat that will see it's fair share of abuse and for this reason I constructed the pulpit out of stainless steel. Most of the items I build out of stainless steel are going to get painted, but I want the stainless underneath the paint for the lower maintenance it will provide. I made the pulpit using 1.5" sch. 40 stainless pipe, and sheathed it in 3/16 stainless plate. All the stainless is of the "L" variety ( low carbon), and all of the stainless came used from the scrap yard costing about 30 cents on the dollar. I love going to the scrap yard and I'm always amazed at what gets thrown away. I added a front door that bolts on to the pulpit so that I would be able to paint and maintain the inside of the frame, and also for some storage. On the port side of the pulpit I added a recess for a wash down hose and a line for compressed air. Compressed air in my opinion is such a handy tool, I want it at both ends of the boat.
I'm planning on using a Maxwell hydraulic windlass with chain rode to starboard, and rope rode to port. I looked through the marine catalogs and for what anchor roller assemblies cost and how light duty they appeared to be I decided to build my own. Once again I probably went a little overboard but I've seen boats with the anchor rollers twisted off of them, and I have a strong opinion that one should not compromise on ground tackle and it's related infrastructure. I constructed the anchor rollers out of 1/2" stainless steel. To give the roller frames a more finished look I wrapped the roller frame with a piece of 3/4" stainless round stock. T

拖网渔船建造

拖网渔船建造

his round stock will make the paint stick better, it gives a much more fair edge, and is much more friendly on ones hands and feet. I turned the chain roller in my lathe out of a piece of 6" stainless round bar I found at the scrap yard. I turned the roller in such a way that my 3/8" anchor chain will lay down flat in the roller with a groove for the chain to ride in. I'm hoping that this design will prevent the chain from twisting as it comes home. The spindle is 3/4" round stock and I used two sealed bearings pressed in to the roller to prevent wear on the shaft and my roller. The shaft is pinned to the roller frame through a 3/4" boss's I turned in the lathe and welded to the frame. I made the rope roller frame the same way as the chain roller frame except that I purchased the roller wheel from a marine supplier.

 楼主| 发表于 2015-6-27 22:48:15 | 显示全部楼层
I built the forward handrails out

拖网渔船建造

拖网渔船建造

of 1.5" stainless sch. 40 and the uprights are 1" stainless sch. 40. I installed the 1" uprights at the same angle as the reverse rake of my wheelhouse windows. I ended up making a full size plywood template of the curve of the boat and used that template on the shop floor to bend the pipe. To cut the uprights I first used a chop saw to cut the miter where the uprights weld to the bulwark cap, then I clamped the pieces in my mill vise at the correct angle then used a hole saw to cope the joint where the upright welds to the rail. All the uprights are welded directly above a frame on the bulwark, and are extremely stout with absolutely no wiggle in them at all. I'd guess one could tow the boat with these rails if one wanted to. I'm going to polish the rails and leave them shiny vs painting them. The height of the rail off of the deck is 42" and all who grab a hold of the rail commen

拖网渔船建造

拖网渔船建造

t on the good height and how secure one feels by being behind the rail. With the addition of the swim platform and the bowsprit, the overall length of the boat is a hair under 49'. She's still 44 as far as the harbor bill is concerned ( that's my story at least)

 楼主| 发表于 2015-6-27 22:50:45 | 显示全部楼层
Main Engine

拖网渔船建造

拖网渔船建造

Being an excavating contractor has given me reason to be very familiar with diesel engines. A gasoline powered engine has no business on a boat like this so the choice for diesel was one of my easier decisions. I own and operate CAT powered equipment and have had very good luck for the most part in regard to longevity. I began my engine choice with the power requirements of the boat as recommended by the designer ( 120-175 hp ) and began looking at various manufactures. I looked at CAT, Deere, Cummins, and Yanmar. I chose to go with Deere engine model 6068TFM.
I chose the Deere over the other manufacturers for a few reasons. Deere was the only engine in this horsepower class to offer wet cylinder liners. If I ever have a catastrophic engine failure I could re build this engine inside the boat as I would more than likely be replacing cylinder liners vs having to remove the block to have the cylinders machined ( as with all the other

拖网渔船建造

拖网渔船建造

manufactures engines). The Deere engine was also the only engine not to be computer controlled in this class. The only electronic part on the Deere was the fuel shutoff solenoid. Deere has a solid reputation in the Marine industry and parts are readily available throughout the world. I'm not saying anything bad about any other Manufacturer, but for simplicity and ease of possible future repair work, the Deere made the most sense for me.
Deere has a rating scale for horsepower output calling the rating M1 through M4. The M1 rating specifies the engine running at continuous duty generating 154 hp. The M4 rating is for one hour of wide open throttle once every 12 hours generating 225 hp. At 1600 rpm the engine will burn about 2.4 gallons per hour moving the boat about 10 miles translating into approximately 4 miles per gallon. Even though this is a full displacement hull, I'm thinking 4 miles per gallon to be wishful thinking, but I'm hoping I'll see 3 mpg. With my 1400 gallons of fuel ( 4 integral tanks) I should see a range on the dreamy 4 mpg of 5600, but I expect a realistic range of 3500-4200 miles with a fuel burn of 2.5-3 miles per gallon. I'm a boater who likes to travel slow a watch the world go by. I'm more interested in fuel savings than my ability go get someplace an hour early. I don't want to abuse the engine by running her to lightly as I understand that diesels are happiest when they are feeling a little bit of a load, but I also doubt one will catch me running wide open too often.
My main engine will have dry exhaust exiting the boat through a centralized stack out through the cabin roof. Fresh air for the engine will also intake via this central stack albeit a second compartment within the main stack. Cooling the main engine will take place via a Keel cooling system. Instead of taking in sea water to cool the engine, I'm using a grid type cooler welded to the hull that will act as a radiator. Keel cooling was another decision that I researched and decided on this method for it's pure simplicity and reliability. Most of the commercial boats out in the world use keel cooling as it is extremely robust and reliable. Keel cooling and steel boats seem to go hand in hand.
My transmission is a Twin Disc MG 5050A. The gear ration is 2.05:1 and I have a 5 degree down angle on the output flange. I ordered the Twin Disc with a PTO to power my hydraulic system. On the installed picture of my engine you can see the Eaton load sensing variable displacement pump bolted to the back of the Twin Disc gear. My prop shaft is 2" Aquamet and I went with a 4 blade 30" prop with an 18" pitch. The engine is standard rotation ( counter clockwise) so that makes the propeller a right handed prop. The prop shaft seal is of the drip-less variety. I used Vesconite for both my cutlass bearing and my rudder bearings. Because of the length of the prop shaft and wanting to stick with the rule of thumb for bearing spacing and shaft diameter, I added a pillow block bearing to carry the shaft between the stern tube and the coupler. I'm intending on installing line cutters on the shaft, and a drive saver type coupler.
I'm thinking of adding another handrail around the engine to help me walk through the engine room. As I have it set up now there is a natural flow as to how one grabs the upright, then the "U" shaped rail, but I do think it would be safer and if a horizontal rail were added between the upright post and the "U" shaped rail to witch the tranmission cooler is bolted to. I am also giving serious consideration to constructing a sound shield for the engine. The sound shield would give the engine room a more steralize look, but it would also make for a very quiet boat.
 楼主| 发表于 2015-6-27 22:52:37 | 显示全部楼层
Bow Thruster

拖网渔船建造

拖网渔船建造

My current boat is a single screw ( one propeller, one engine), and the trawler I'm building will also be of the single screw variety. While my current boat is much smaller than what I'm building I've never had much of a problem maneuvering her around yet I'm choosing to install a bow thruster on the trawler. A bow thruster is basically a propeller in the bow of the boat driven by either an electric motor or a hydraulic motor that aids the captain in maneuvering the boat.
Choices for powering a bow thruster are either electric or hydraulic. While the electric models are more affordable and a little easier to install, I've chosen to utilize hydraulics as my power source. I going the hydraulic route for a few reasons. Hydraulic power is much more reliable than electric ( component corrosion is a non issue). Hydraulic units have a continuous duty rating unlike electric thrusters that are only able to be used for a few seconds at a time( the electric motors over heat, and the electric motor consumes the battery's charge quickly due to the huge amperage draw). By the time I figure on a separate battery bank, separate charger, cable runs, buying new batteries from time to time, reliability and failure when one needs it most, I feel hydraulics will be cheaper in the long run. I own and operate some excavating equipment that is 20 years old. I've never had a hydraulic failure on any piece of equipment other than a hose breaking, and it is safe to say that this equipment takes a beating. I can also tell you that breakdowns due to electric components, while not an everyday event, do happen and tend to cause things to come to a grinding halt.
After searching high and low I decided upon using a hydraulic thruster engineered and built by Key Power Inc. Key power is a Canadian company and I must say that all my dealings with them have been great. I've yet to purchase my thruster, but they gave me good advice on sizing the unit and have been helpful with the hydraulic system as a whole. As much as I wanted to keep my purchases in the states, Jim at Key Power was the only vendor who actually acted like they wanted my business and wanted to sell me components. Good people.
The actual thruster is housed in a 1

拖网渔船建造

拖网渔船建造

0" sch. 40 tube welded into the hull. I built a sled to rest the tube upon so I could scribe the cut out on the hull and scribe the shape of the cut on the tube. The sled made this job go pretty smooth. After I cut the hole and scribed the tube, I slid the tube into the hull and marked the other end and cut the exit hole. Once the holes were cut I fabricated doubler plates to weld to the hull on the outside of the hull. I slid the tube back through the now doubled hull and marked the tube for final cutting. A few hours of grinding and cutting and I was happy with the fit of the tube. I blasted the mill scale off of the tube before the final install with the hope of saving some blasting inside of the hull. I had welded some gussets inside the hull that would be on the bottom of the tube once the tube was installed with the end result being a water tight bulkhead below the tube. Once the tube was installed the final welding took another day to complete. I did not have to cut any frames to install the tube, but I did have to cut two longitudinal stringers and weld them back to the thruster tube. I've been told that the deeper the tube is in the water the better it will perform. Keeping with that thought I was told that the minimum depth on the tube was one tube diameter below the water line to the top of the tube. I think I'll fabricate a grill of some sorts to keep trees and heavy drift away from the prop.
The bow thruster tube cut one of my ballast boxes in h half so I'm going to have to be careful on maximizing space for my ballast. I measured t

拖网渔船建造

拖网渔船建造

he cubic footage of the halved ba

拖网渔船建造

拖网渔船建造

llast box and by using lead shot, I should be OK in regard to the amount of ballast in that area. The bow thruster motor will be housed inside of a water tight box welded around the tube accessed under the forward sole. I don't know if the water tight box is over kill, but if something grabs a hold of the thruster prop and rips things apart, the water tight box might come in handy.
Looking at the completed job all I can think of is how I just cut a big assed hole in the bottom of my boat. While the money I'm going to spend on the thruster is not small change, I'm looking forward to the added maneuverability my little steel trawler is going to have.

 楼主| 发表于 2015-6-27 22:54:57 | 显示全部楼层
Emergency Tiller

拖网渔船建造

拖网渔船建造

Not that I'm counting on the steering system failing, but I do want to make sure I have a back up method of steering the boat.
I'm using a hydraulic steering system on board that is similar to a car. I have a pump mounted to the engine witch powers the helm station witch sends oil to the hydraulic cylinders that are bolted to the rudder post. In the event of a failure of the steering system, I can by pass the hydraulic system and attach a manual tiller to my rudder. I should probably note that I had the end of the rudder squared off for this reason.
The emergency tiller consists of a tiller, a custo

拖网渔船建造

拖网渔船建造

m made end to fit over the rudder and into the tiller, a bearing welded into the deck, an "O" ring seal, and a cover. All this was designed by me so I have no one to blame if it self destructs. I have tried it out, and I must say it goes together quickly, and locks on to the rudder rather well. It seemed important to me to have the tiller on deck so the tiller mate and the helmsman could communicate.
Conall

拖网渔船建造

拖网渔船建造


拖网渔船建造

拖网渔船建造


 楼主| 发表于 2015-6-27 22:55:54 | 显示全部楼层
Generator

拖网渔船建造

拖网渔船建造

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.

 楼主| 发表于 2015-6-27 22:57:36 | 显示全部楼层
Cleats

拖网渔船建造

拖网渔船建造

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

拖网渔船建造

拖网渔船建造

. 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 a

拖网渔船建造

拖网渔船建造

lso have a sampson type post on the swim platform for the sole

拖网渔船建造

拖网渔船建造

purpose of tying off my dingy when she's not stored on the cabin roof.
Conall

 楼主| 发表于 2015-6-27 22:59:11 | 显示全部楼层
Fairing the hull

拖网渔船建造

拖网渔船建造

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.

拖网渔船建造

拖网渔船建造

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 lo

拖网渔船建造

拖网渔船建造

ng 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.

 楼主| 发表于 2015-6-27 23:00:38 | 显示全部楼层
Water Tanks

拖网渔船建造

拖网渔船建造

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 o

拖网渔船建造

拖网渔船建造

f 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 welde

拖网渔船建造

拖网渔船建造

d 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.

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