Exhaust pipe heat?

[devovino]

Just have a quick question regarding the potential heat of the dual exhaust that run under the floor. Over last winter when I replaced all my interior, i found rot under the rear seat so I pulled up all the floor under the rear seats and dug out all the foam, and made new bases for the seats to rest on, this is temporary because I know I will be pulling up the floor and replacing floor/stringers when I get motivated, probably this winter. To get to the point, now when you lift up the back seat cushions, you can see all the way to the fiberglass that is the bottom of the boat, and see the exhaust running back. There is enough space for me to put two fat sacks (phat buddies, 250x2 one on each side), but am wondering how hot the exhaust gets if they will melt the phat sacks? Now that I think about it I could probably just feel it after running hard for a while..... But they put foam all up against them and it does not melt, so if anybody has any input it would be appreciated, and remember no question is a stupid question.... ;-)

[OUI]

The temp of the pipes is the same temp on your temp gauge, maybe a little cooler. Call the manufacturer and ask them if they can handle the heat.

[devovino]

Yeah I think I will just frame in the dual exhausts, I used 2x12 for the seat bases so I am just going to box out the exhaust and avoid any undue great transfer. I am interested in hiding all my ballast bags so I can have floor/seating space. I did build a box similar to sybermike's behind the drivers seat which wool hold my 800lb phat sack, and work ad storage space when not in use. I will take some pictures if anybody is interested. Hitting the lk tomorrowand will get some footage of me wake as well!

[cadunkle]

So you can fit a 250 lbs sack under the floor on each side of a Saltare? I was under the impression it's really tight under there. If it can be done, that would be awesome.

[devovino]

Indeed it is a little tight, so some of the bag is pushed upwards towards the seat, but it works. The "phat buddies" fit perfect however, and the have a protective case with handles/webbing for straps so you can position them as you fill. I am really leaning for this winter when I tear her down, I will pull the gas tank and remove all the foam and the remaining outside stringer ( maybe I forgot to mention I cut out the outside stringers on both sides, they were rotted out) and use all the space from the transom to behind the drivers seat, or the observers seat on the port side to glass in some under floor ballast, just glass everything heavy, add some baffles and should give me some considerable weight under the floor. Another member on this forum did it with his boat, his name escapes me at the moment but he also sold his boat for 18,000 dollars later down the road. He did a total cap off restore, made a jig to flip his hull and re-gelcoated his whole boat. I got confirmation about being able to put under floor ballast from him. I will try and find his thread, a hell of a rebuild, I am sure some of you remember whom it is. Anyways, time to go trim out a door I replaced a window with- have to keep momma happy! Have fun, surf it up!

[92SupraComp]

the temp of the exhaust IS NOT THE SAME AS TEMP GAUGE! exhaust gas coming out of each cylinder under no load is prob around 300-400 degrees, under a good to full load easily over 600 degrees. the temp gauge just reads engine water temp. but once the water is mixed in it boils creating the steam you see. but the temp of the exhaust is still rather hot. above 200 degrees.

[SquamInboards]

You're right that the temp of the exhaust isn't the same as the engine block temp but exhaust hoses should run under 150F, and the standard rubber exhaust hose is only rated for 200F continuous, 250F intermittent. When I had a problem with a partially collapsed hose they would get up over 300, which was clearly a malfunction and I have since corrected it; with proper water flow the exhaust after the manifolds should be under 200 for sure. So I'd ask if the fat sacs can handle 200F, which seems pretty likely.

[devovino]

Well whatever temp it is does not seem to be a problem for the foam the sprayed below the floor, because it is all around the exhaust. Either way I believe I eliminated the problem by framing in the exhaust, I made a box that conceals the exhaust and separates the phat buddies from the exhaust. I just want to avoid any problems, like the 2x 250 lb sacks rupturing and flooding the bilge, so lets just stay away from the problem all together. Hopefully over the winter I can glass in some below floor tanks to eliminate the need for the phat sacks, see how motivated I get....

[cadunkle]

I don't understand how you are positioning sacks under the floor with handles. Once it's in, I'd imagine you have very little room to do anything given the length adn space constraints. You're talking a compartment a few inches tall outside of the main stringers.

[devovino]

Cadunkle, the space under the rear seat with the floor removed, and the outside stringer gone is actually about 24 inches from boat floor to the underside of the seat cushion, and about 25 inches long from front to back, there is more room if I redesigned the rear seat base, I think a picture is in order to be able to visualize for you, I will see if I can post one tomorrow when I get of shift. But there is a bit ofspace that is usable under the floor too the bottom of the seat cushions.

[cadunkle]

Oh, to bottom of seat cushions. That isn't very relevant though. You cannot run without secondary stringers (I sure hope you're not), and most people want a floor, though I suppose it's not necessary. I suppose you could raise the floor or have a subfloor. I've seen a raised floor on a SN2001 where the floor was only a couple inches at most below the gunnels.

[devovino]

Well floor is overrated! Haaa JK, but the floor under the rear seat for my is not really needed at this time, and it was rotted out as was the outside stringers on both sides, so I removed them. I have been running with out the outside stringers pretty much since I have owned the boat, but to compensate I installed 2x12 ,front/rear of the seat bases that are notched out to slide over the existing main stringers, and 2x8 that run along the outsides of the rear seat bases to also box out that area, so I am sure it is stronger than it was with rotted out stringers. I am sure I will modify all of this when I rebuild it this winter, adding under floor ballast. It work for now, and I believe it is stronger than it was originally. I will attach some pics of how I installed the seat bases.Granted this was early in the rebuild so the outside stringers had not been all the removed, they have been since ground down.1095410955

[devovino]

Here is what it looks like after the rear bench was installed.10956