Plumbing System Design

[knottybuoyz]

Thanks Freeze

Minor revisions. P/W intake moved as far as practical from fuel & waste deck fills. As much as I'd like to have them at total opposite ends of the boat it's not really practical when you try to balance convenience vs. long hose runs. The fuel fill and waste fills will be at least 1' apart and the fuel will have a locking cap. I don't think anybody will want to steal what's in my holding tank eh? The P/W fill is recommended by ABYC 23.8.6 on a vertical plane so if I put it on the face of the step at the sheer it'll work very nicely and be tucked out of the way.

[Talbot]

Having looked at the latest picture, here are my comments.

80 gallons of fuel and only 75 gallons of water would appear to be quite a large mismatch unless you expect to have to do a lot of motoring?

I have seen a lot of cruising boats with 175 gallons of water and less fuel (including 5 gallon containers) than you have tanks.
I would also be worried about the effect on trim. You also show 50 gallons of waste - seems a bit excessive, but that will depend on how you expect to operate, and I do understand USCG do police this.

Another point to ponder, the boat I am considering has been deliberately designed so that the water run off from rain concentrates into a spot where there is a fresh water tank access, so you can allow the initial downpour to clear the sails and drains, and then block the overspill behind the drain, so that the majority of water falling on the boat can be captured in the water tanks!

[Pblais]

50 gallons for waste does seem a lot especially with two tanks. There is no future in storing more waste. The longer you keep it the more problems you have. Making it 25 and adding the extra tankage to fresh water seems maybe a more balanced approach.

The last boat was 120 water, 20 waste and 60 fuel. This was a sail boat. The water will last 4 days if you cruise with my wife. She isn't really bad but we don't conserve a lot that easily. The waste tank will last longer than the water but not as long as the fuel. The fuel was good for a really long time. It just seems like you would run out of water before you filled the waste tanks.

[knottybuoyz]

I guess we're lucky in that we'll be boating right in the heart of some of the greatest fresh water reserves in the world. I don't ever see "us" going offshore with this boat and need to capture f/w from rain. Around here, you can't go more than 20 mi without finding a marina with f/w and pumpouts so the need to store lots really isn't a consideration. I can easily reduce holding to one tank. Our current boat has a 6 gal bladder that we can get 5-7 days service from if needed.

The 70 gal of f/w is a "nice to have" 'cause the Admiral will drain half of that with a single shower although she'll only have 11 gal of h/w and not 40!!! Our normal day-in day-out boating will require just 'nuff for doing the dishes after dinner. We would only need to fell 'em up when we head out for our annual 3 week tours of the inland waterways and even then it isn't "essential" to haul that much water.

80 gals of diesel will probably get us through a complete season w/o the need to refuel. I think the designer estimated a 1300-1500 nautical mile range with that fuel capacity. Again, for normal day-in day-out boating it's unlikely they'll ever be full. Under normal conditions with near empty tanks we'll probably have to add ballast to get her down on her lines. We're discussing modifications with the designer so that's one consideration I've asked him to pay special attention to.

Anywho, thanks for all the input I appreciate it.

Rick

[GordMay]

Actually, DeepFrz raises a very good point.
In order to ameliorate water pooling & eventual leaks, all horizontal deck & house penetrations should be on either:
1.an inclined surface
or
2. a raised pad
or
3. both

[knottybuoyz]

The side decks aren't perfectly flat. If I remember correctly they're about 5/8" lower at the sheer over the 10" that they are wide. Would that be 'nuff?

How 'bout if I recessed them in a pocket 'bout half way between the side deck and the bottom of the window? I'd slope them about 45 degs.

[44'cruisingcat]

Originally Posted by Talbot

I have water heater in one hull and an outlet in the other hull. Originally this was in 15m plastic pipe, and took a lot of water before getting warm. A lot of heat was wasted on such a long pipe.

I had a similar situation. I fitted a hose and tap to recycle the water back to the tank. I can open that valve until the water gets warm, then have my shower, without wasting too much. (water)

[GordMay]

Adequate drainage requires a minimum 1% slope (± 1/8" per foot), with 2% (1/4"/Ft) preferred; hence your 6-1/4% slope (5/8" ÷ 10") will be more than adequate to prevent ponding.

Notwithstanding, I prefer to see deck penetrations on raised “housekeeping pads”, which are homogeneous with the (adequately drained) deck.

Cruisingcat’s “manual” hot water recirculating system is a good idea for conserving water. Obviously, pipe insulation is also recommended on all hot water distribution.

[GordMay]

Rick:
I’m certain you’re familiar with Transport Canada’s Marine Safety Publications, particularly:
TP 1332 E ~ “Construction Standards for Small Vessels”
http://www.tc.gc.ca/marinesafety/TP/TP1332/menu.htm

Including Fuel Systems:
http://www.tc.gc.ca/marinesafety/TP/TP1332/section7.htm

[knottybuoyz]

Hi Gord

Yup! Got 'em right here in front of me. I plan on having the boat inspected during construction so I can register it. I have a half dozen colleagues who are TC Ship Safety Inspectors and Marine Engineers so I'll tap their expertise when I'm very close to the final design. I think they'll be impressed that a "Logistics Officer" (purser) can do this kind of work!

Today's revision. Reduced holding tank to 1 and enlarged to max. space available (it actually may end up smaller). Pumpout deck plate on Stbd side only now. I can live with that. Indicated sizes of other tanks. Relocated h/w heater. I think the basics are there now. I'll refine the BOM later. Mr. Rick gave me plenty to think about on the electrical system discussion which I have to absorb.

[Brent Swain]

A couple had to motor off a lee shore in central America. The fuel tank was almost empty. They had fuel in gerry cans but couldn't put it in the main tank because of heavy water on decks. They only had those goofy ,trendy, yachty , flush deck fillers. They made it , then put proper fuel fillers in.
Stainless tanks , if they are too thin, tend to crack the welds around the ends,from metal fatigue, from liquids sloshing around in them,. Building them with radiused corners, or cuttting a pie shaped slice out of the ends, welding it up and thus giving a slight cone shape to the ends helps a lot, as does putting the ends up against a solid plywood bulkhead.

[DeepFrz]

How 'bout if I recessed them in a pocket 'bout half way between the side deck and the bottom of the window? I'd slope them about 45 degs.

I take it that you mean recessed into and partway up the cabin side? If so that should work very well.

Deep

[knottybuoyz]

Originally Posted by DeepFrz

I take it that you mean recessed into and partway up the cabin side? If so that should work very well.

Deep

Yup! Saves wear & tear on the knees too while fueling etc. Glad I thought of it huh?