Pearson 30 questions...any answers?

[tac]

Pearson 30 Hot Exhaust

When I rebuild the hot section, in order to reduce back pressure I reduced the three 90° turns to one by replacing the two els with 45° pieces. This also made the whole assembly a few inches shorter in length which meant moving the waterlift forward about 6", a modification that took about a half hour. All pieces downstream of the mixing tee are 316 stainless from McMaster.

[tac]

Pearson 30 Hot Exhaust

Here is a drawing of the present hot section.

[rockhopper]

How is this water scoop thruhull for the raw water engine intake supposed to seal? I can wiggle it which concerns me, I wanted to try to install a ball valve to replace that spicket valve.

[ndutton]

Please read the following articles:

http://www.pbase.com/mainecruising/replacing_thruhulls

http://www.pbase.com/mainecruising/external_strainers

[rockhopper]

What size was the raw water thruhull for the engine cooling size? Mine had an external strainer facing forward (read that was a bad idea as well since it could scoop up the water and overflow back into the engine when the engine was off) and a 3/8" gate valve. Don and Ken both said that was too small so I was just curious as to what size Pearson had used.

What size was the wet exhaust port on the aft of the boat? Mine I think is 2".

[Tim]

My Pearson 10M had a 1/2 inch thru hull and valve for the engine water intake. As noted above, I recently installed a 1/2 inch Marlon seacock, thru hull and strainer.
The exhaust outlet on the transom is 1.5 inches on my boat.

[tac]

1978 Pearson 30 OEM through hull sizes (hose I.Ds. are the same):

Engine exhaust 1-1/2"
Cockpit scuppers, port & stbd 1-1/2"
Engine raw water 3/4"
Galley sink drain 1-1/2"
Head flushing water 3/4"
Head sink drain 3/4"
Head (toilet) overboard discharge 1-1/2"
Holding tank overboard discharge (macerator pump) 1-1/2"

[rockhopper]

The smaller hose is a 1 1/2" hose from the old water lift muffler, the bigger hose went to the exhaust port on the aft. So I'm not sure but I'm almost certain that one hose is bigger.

[tac]

In your pictures, if the left hand hose from the waterlift heading aft to the transom is 1-1/2" I.D., and the right hand hose that you apparently cut off the fitting, is, say, 1-3/4" I.D., then:

1) Somewhere between the waterlift exit port (which should be 1-1/2" O.D.) and the transom fitting should be a 1-1/2" to 1-3/4" hose adapter.
2) This adapter could be metal (good) or of plastic (not good - it can melt, or be eaten up by acids in the exhaust). This fitting might not be visible, but you should be able to feel the hoses change size.
3) Take a calipers or good tape and measure the O.D. of the transom fitting. This will confirm the hose size you need at the transom.

I see no problem in using a hose adapter if it is corrosion resistant metal, and if hose clamps are used on both sides.

[rockhopper]

Is the fuel line sized differently? I purchased some new 1 1/2" fuel hose for my tank, the smaller hose on the left wouldn't tighten up enough on the cockpit scuppers but the new fuel line fit the scuppers great..perhaps this hose was just old and worn. I will take some measurements of the items I have at home in the morning.

Yes, after the hose left the muffler it hit a 90 and the hose got just a little bigger.

[tac]

In general, all hose fittings are specified by O.D. (outer diameter) of the part the hose fits over.

In general, all hoses are specified by I.D. (inner diameter) of the hose

The above are NOT true for pipe and tube, which have their own standards.

The fuel fill fitting (called a "spud") should be 1-1/2" O.D. The spud fitting MUST be metal and be grounded (Coast Guard requirement). The hose fitting at the forward top of the tank should also be 1-1/2" O.D. and must be metal (Coast Guard requirement). The hose between the spud and the monel tank is 1-1/2" I.D. and must be A1 hose and ethanol rated.

Scupper hoses. You've probably noticed it is difficult to flex and twist 1-1/2" hose to fit between the scupper and the sea cock. A solution is to sketch and measure the two bends that are needed, go to a NAPA auto parts store, and ask them to search through their stock of 1-1/2" radiator hose for one that matches.

[rockhopper]

Okay measured the old Venalift water muffler and the hose, O.D. of the muffler is 1-1/2" as well is the hoses I.D. The replacement fuel hose I purchased was a tighter fit on the scupper versus the old water lift muffler line (perhaps the muffler hose is worn out).

I ended up just cutting part of the new fuel hose since I had to buy 12" of it and the connection to the tank is less than 6" and using it to connect the scupper to the fiberglass tube.

I ended up just pulling the scupper out of the cockpit because it was leaking rain water all into my bilge, cleaned up the old sealant and put some 5200 around the flange and put the new hose on.

Tim did you post anything on the install of your thruhull? What are the benefits of using the Marelon thruhull versus a bronze thruhull? From what I understand the backing plate is a must have? I'm just confused because the one that was on the boat was a bronze thruhull & strainer combo (strainer was facing the bow) and the only thing holding it on was the nut inside and one screw grounding the strainer to the engine. When I pull the old screw out that grounded the strainer what do I use to seal the hole? Don't think I will put an external strainer on in case I ever need to unclog the thruhull from inside the boat as the strainer would prevent that. Thanks again for all your help and support.

[Administrator]

Backing up a bit....

Nota bene part #11 in the Pearson drawing.

Bill

[Tim]

The only benefit of Marlon over bronze is that I could not find a bronze flanged seacock in 1/2 inch. I did make a 1/2 inch fiberglass backing plate, but it probably was not needed. Pearson made the hull thicker around the seacocks(like built in backing plates) and the hull is approximately 3/4 thick near the engine intake.

[sastanley]

RH,
We need to get Ajax to come back over from the dark (diesel) side and help me recollect what we did on his engine intake. I know we put in a new one, and I am pretty sure it was marelon, but I dunno if he "upsized" it or not.