Question # 1
As mentioned by Jhall those upside down P traps stop water from upstream water sources from dumping back into the bilge. However one could also , at least consider using what is call a Sanitary Tee which has the Tee part on a long angle to join with the main run. That would also prevent back flow. Just be sure that the actual Tee is on a slight down angle to the main run as an extra precaution. The Sanitary tees would flow better from the individual sources. It may not be worth the work and effort though.
Q #1.5
the back flow when you use a bilge pump indicates to me there is a plug or restriction in the main line. Get yourself a SMALL plumbing snake. THey are inexpensive at the local plumbing supply and use it to break up any restrictions. THis is actually where the Sanitary Tees would shine over the P traps. THe San. Tee would allow the snake access already aimed in the exit direction. I will suggest that cleaning should be done periodically to prevent this. I go through something similar on my back deck. There is a gutter which collects all the deck run off from the entire deck area. THat gutter needs to be cleaned several times a year. Just did it and it was loaded. You may be able to rig one San. Tee near the beginning or the pipe run so a hose can be attached, turned on and the water can blast debris out the exit.
Question #2
Sorry but this makes no sense. How is a belt split by a water hose? Why is the rad. cap a suspect? As far as the rad. cap pressure rating is concerned you need to go to the engine supplier and since you don't say what the engine is I am going to guess it is either a Ford Lehman, a Perkins 6-354 or an old Cummins 6B engine. All around 120 to 160 HP.
-- Lehman contact AMERICAN DIESEL who are the Lehman gurus.
https://americandieselcorp.com/
--Perkins contact Caterpillar whno bought Perkins about 15 yrs or so ago.
--Cummins should have a dealer in your area.
Try and find out the specific model and its serial number.
I just had a brain F... It's a Lehman. THe hose routing at the engine front pushed most owners into tieing a spare belt in place because one of the hoses has to be routed through the belt. This must be done at the time of a coolant change or the coolant must be drained to install the belt in case of a belt failure. THis is a needed technique on this engine. Most engines the belts can be installed without dumping coolant and pulling hoses even though they too may prevent difficulties but not like the Lehman. If I'm right then take a good look at the modification so you can duplicate it when the belt and hose ages.
# 3
Injection pump drain plug. Best is to repair it properly. However that usually means pulling the pump off and sending it to the repair shop. Any metal chips introduced into the pump may wreck it at considerable expense.
#4
Never heard of Blue Steel. Is it one of the myriad of phosphate concoctions that will turn light rust black stopping any further rust? They do work if that is what you are referring to. However, the part must then be painted as the treatment is not rust proof in and of itself.
Which through bolts? The ones through the stringer, the ones through the mounts and through the steel mount adapters to the stringers?
If it is the engine height adjustment posts I would try to loosen the nuts and soak the threads with a good penetrant such as PB Blaster, KROIL, and so on. Kroil is one of the best. Leave the bottom nuts alone untill the top one is loose and free. Then tighten that top nut and then do the bottom nut. THat way you will not lose the adjustment so once the bottom nut is loose and free it can simply be retightened. If you just go undoing all you will end up with a BIG job of realigning the engine[s]. Leave that for another day. If they are fighting too hard leave it alone untill you have a LOT of time. Not ignore it. However soak the nuts as well as you can with your penetrant and reapply over several days if they are not co-operating. You can also try using a drift /rod and striking the drift with a hammer to shock the nuts after penetrant wetting. The shock should help the penetrant to penetrate the rust.
If it is the engine mount securing bolts through the mounts and the adapter steel angle to hold the actual engine mount in place, sure, but just replace one bolt at a time. You may be able to clean them but I will repeat, one mount at a time, so you don't upset any adjustments.
If the bolts are those that secure the steel bracket to the stringers, then again do one at a time. If the bracket shifts you may have a big problem. \The engine should probably be supported by a chain hoist from above or some blocking from below using a jack to fit the blocking. Just be very cautious and do not use the oil pan. If you damage that then you have a big problem.
#5
draining may help. I would rig a fan to blow through the holes. Over time the moving air will dry the wood out. Yes it works. It also takes a long time. I did the same thing on my boat many years ago. High bilge water hid the hole and filled it.. I used small line stuffed into the hole to soak the water up leaving about a foot out of the hole into the bilge. The water soaked into the line and the line carried it to the bilge and there was a stream of water running away. Once the bulk water was gone I used a small muffin or computer fan to blow through the hole. The water would be evaporated and slowly dried the wood. Each time we went out I installed a bolt with a heavy buildup of rubber washers to seal the hole and when we came back the hole was opened and the fan set up again. The bilge water had to be controlled.
It took me several years to be OK with the job. And yes 35 yrs later, we still have the boat. Once I was happy with the dry out I sealed the hole[s] with epoxy and cloth. I eventually got hold of a moisture meter and it shows dry enough to not be a problem.
If the stringer is really wet then Git rot, at least to me , will not repair the stringer and may seal damaging moisture inside. It may be worthwhile finding a moisture meter and using it to monitor the drying process. ELectrophysics is one, I have the swing needle type, They are not foolproof but a good guide about the process.
You might even rig one fan to blow air into a hole and another fan to suck air out so you force some circulation, however little.
But get and keep the bilge water under control as a priority.
#6
Which pump specifically are you referring to. The Vacuum generation pump or some thing else.? Even the holding tank emptying pump is virtually the same unit but just with one set uf duckbills.
Even If the vacuum pump for the vacuum tanks they should not be anywhere near $1,200 or maybe the entire pump as a new one..
I have that pump to empty my holding tank although in my case it is the unit with only the single set of duckbills, not the twin duckbills that the vaccum generation pump uses. The pumps can be rebuilt unless the caseing is cracked and/ or the motor is ruined. The duckbill valves, the plunger seals, the case sealing O ring can all be replaced if you are willing to get you hands dirty. Wear Nitrile gloves and some care. Just take some time and be prepared for a dirty job.
#7
I too have lead sheeting. Periodically I have to restaple parts of it. Use some heavy paper or light waxed carboard or paper to shoot the staples through. Best are either bronze or SS staples. If you have an air or H.D. electric stapler even better. You may even consider some thin wood strips and shoot or screw through those to spread out the load from the staples/screws.
# 8
Inverter. Sure but you do need to do some research on your own here. You need to examine what you want to run, how much power those devices will use or you will likely make a poor choice. You have AC shore power. An inverter is fed by the batteries. The batteries must be charged by the battery charger which must be fed by the shore power.. So the inverter must draw down the batteries to run. It may work to run the battery charger constantly and then use the inverter to run a high current load such as a microwave or kettle, which runs for a short time at a current high enough to cause the shore power to trip the breaker but then the load must be off long enough for the charger to do its job and replace the power the inverter pulled.
This question you must do some serious thinking about. More than can or should be dealt with just here.
# 9
Refer to Jhalls post. He makes a very good suggestion.
And I too am going to suggest that you don't load all these questions into one long post. Split them up over a bit of time. THere is another poster, new person, Ducattihottie who also has had many questions but splits them up somewhat. You will likely get more detail for each question.
There are many posts about inverters and so on so do a bit of looking especially in the Electrical threads.
Before I go I will strongly advise to cover the shaft stuffing boxes with some cut up old small fenders. They do not have to be pretty.
All stuffing boxes spray water, maybe not much but they do spray. THat spray can be a mist that will travel and cause rusting of the back end of the engine, the gearbox and any other steel parts nearby. It can travel and if the spray is heavy enough quite far.
Cut the ear off leaving a hole a bit bigger than the shaft. Cut the piece long enough to be secured to the stuffing box and overhang the shaft entry into the stuffing box by an inch or so. Doesn't need to be a lot. Then split the fender piece lengthwise so it can be put over the shaft entry and secured in place with a Tyrap or a worm gear clamp.
The holding can be quite light duty as this is only a cover. Set it so the split is down. That way the spray will be caught by the fender and drop into the bilge instead of spraying all over the area.
For mine I can have the cover off in about 20-30 seconds. I use a Tridon clamp and hang the nut driver nearby so I don't have to search or dig for it.
Have fun.