I have a couple of questions regarding the raw water intake and any upgrades I need to make during my repower:
1. Do I need to increase the size of the raw water intakes/hoses going from gas to Cummins 6BTA's?
2. If I do not need to increase the size of the raw water intakes/hoses, am I able to have these strainers refurbished and reuse them or do I need to upgrade to a larger size strainer?
John,
You will have to throw everything out from the hull up on those intakes.
Gas was 1-1/4. Those Cummins will be 1.75" and up depending on hp and how you route and length of hose. Thru hull valves need to be full flow which just means the ball part of the valve does not reduce the flow size inside the housing. Any 90's need to be smooth radius curves and not tight 90's. Fluid dynamics dictate that a tight 90 will add 15' of additional hose length in resistance to flow.
I would install external pickup screens to eliminate the expense and space internal strainers and their plumbing requires.
I'll install the external screens. I read the article in the building tips about the angle of the placement of the screens. Am I correct that the location for the intakes will be the same location as the intakes for my gas engines and the screens will mount outside the existing holes in the hull?
Any advantage to going slightly oversized? Groco part # APHS-2000 specs for a max thru hull of 2". That unit is 10.25" long x 4.38" wide. APHS-3000 specs for a max of 3" and is 15.38 long x 6" wide. In looking at pictures of Bob Higgins' boat, it appears he has the APHS-3000's, but it's hard to get a true sense of scale from the photos.
Use a FULL FLOW through hull valve and go up one size on the external strainer... A standard valve is a choke point and full flow valve is actually matched for the size of through hull fitting you need.
JohnV8r wrote:Any advantage to going slightly oversized? Groco part # APHS-2000 specs for a max thru hull of 2". That unit is 10.25" long x 4.38" wide. APHS-3000 specs for a max of 3" and is 15.38 long x 6" wide. In looking at pictures of Bob Higgins' boat, it appears he has the APHS-3000's, but it's hard to get a true sense of scale from the photos.
If your pump inlet size is 1.75, going to 2" is not a problem, but no need to go bigger than that unless your planning on a dive hatch thru the bottom.
Unless you use a 2" mpt x 1.75 hose barb out of the thru hull valve you'll have to reduce at the pump which requires another connection which isn't recommended. Neither is trying to clamp a 2" hose onto a 1.75" fitting which with wire reinforced hose will never happen.
Again check what ever model hp cummins you are using and its pump inlet size and your proposed plumbing setup before you buy your parts.
BTW skip the cheap ideal clamps and use ABA clamps and double clamp all your inlet connections.
John, listen to all the above, start from scratch like Bruce said, you need a lot of of water to keep those cummins happy, full flow valves over size screens, no restrictions, crash valves, easier to do when starting from a through hull. BH
s269.photobucket.com/user/Westwater3/media/b31%20Bahia%20Mar/DSC01915.jpg.html][/URL]
1966 31 Bahia Mar #316-512....8 years later..Resolute is now a reality..Builder to Boater..285 hours on the clocks..enjoying every minute..how many days till spring?
I think I downloaded about 70 pictures off your photobucket page last night to use for ideas. I gotta tell you I get geeked up over some of the stuff most people would just shake their heads at. I LOVED your battery box idea...just brilliant. I can't even imagine how much stronger that is versus the typical shelf. I was also amazed to see how you did the underlayment of the teak coaming. I thought that was really well done also. I didn't realize how much glass work you had done underneath to create the radius in the corners. I had never seen a crash pump plumbed to another part of the boat, but again, what a brilliant idea. Don't ask me how I know, but I know that my FBC will go bow down when it starts to fill up. That was very well thought out to plumb one crash pump forward the way you did. Finally, I loved the double wire chases on each side versus one larger diameter PVC chase.
Maybe all these are someone else's ideas, but Resolute is the first boat I've seen them used on. I really appreciated being able to look through your pictures to see what you had done.
Relative to the Vernatone mufflers that we all started out with, how quiet are the Centubular mufflers?
John, I learn by watching, go to Capt Pat,Paul Mann, Merritt, Scarborough, Rybovich, Resmondo, there you will see true innovation, I just adapted those great ideas to my 66 31 Bertram. Harry once told me that it takes a special vision to see a concept and actually make it work. Jp turned me on to the exhaust, I had a local catch up to me at the end of the season, said "I heard you leave every morning, put a smile on my face every time, commercial growl with a big block bark". I wouldn't change a thing.BH
1966 31 Bahia Mar #316-512....8 years later..Resolute is now a reality..Builder to Boater..285 hours on the clocks..enjoying every minute..how many days till spring?
Damn pretty, but consider this. If you hole the boat, those crash valves aren't going to do the job if she's nose or ass down. Take at least one of those screens off and replace it with a brass hose fitting. Keep 20 feet of flexible suction rated hose where you can reach it to use as a water vacuum.
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