mike tkach

iTrader: (3)

i should have known u r a blowboater

MILD THUNDER

iTrader: (3)

Im no engineer, but not sure i can say i agree with this statement. In a car, where you have a radiator, I understand that running without a thermostat, the coolant will not have enough time to "sit" in the radiator, and cool. It might flow to quickly, and not enough time for a proper heat exchange.

However, with a unlimited supply of cold lake or ocean water flowing thru the engine, not the case. The reason most guys running supercharged engines without water thermostats run oil thermostats, is because the cold water flowing thru the block will not allow oil temp to come up. Oil temp has a direct relation to block water temp. Thats why sometimes, even with a oil thermostat, engines without a water thermostat, can't build oil temp, or takes a long time to do so, even with the external oil cooler bypassed. Any attempt to "slow" the water flow in the block, will lead to high water psi. Use of restrictor plates, etc.

tcelano

I am an engineer, and a prior nuke officer, and I agree. Heat transfer across a metal wall (cooling jacket in this case) is purely a function of the temperature on the hot side vs. the temp on the cold side, multiplied by a factor that is a function of the thermal conductivity. More flow on the cold side=less heating of the cooling water=more heat transfer. On the sub, when we want more thermal power, we kick up the coolant flow by shifting the cooliant pumps to fast speed. The temperatures stay the same, but more thermal energy (BTU) is transferred to the steam generators, and more thermal power can be extracted from the reactor.

Same thing in the condensers. You really have to watch the temperature and vacuum in them. The seawater supply has multiple speeds, and when you want to use more steam and make more power, you have to kick up the seawater flow, or else you start overheating the condensers, and losing vacuum, which will ultimately cause a main steam supply shutdown as a safety measure. I kept religious logs over a deployment, watching temperature differentials, looking for signs of biofouling,. When you have enough instrumentation to look at, i.e. temperatures at the inlets and discharges of everything, and know flowrates, everything becomes very obvious and linear. We often jump to conclusion on our powerboats due to incomplete instrumentation and relatively crappy innacurate gauges. But then again, almost every piece in a nuke plant is worth more than my whole boat.

mike tkach

iTrader: (3)

if i understand what you are saying,it means that the more water you run through the cold side,the cooler it will be on the hot side,makes perfect sence to me.

mike tkach

iTrader: (3)

guess i shoukd mention,if you run a crossover,you do not want to use a thermostat,or the water pressure will increase,because pressure is caused by resistance to flow.this is why some people who switch to a crossover have high water pressure,the water simply cannot flow fast enough through the thermostat,so the pressure increases,espically when the thermostat is closed.

88Fount33

tcelano - Thank you for your service, I turned down the opportunity you took advantage of in 1980, even with a sizable signing bonus offered, I just couldn't take staying underwater for 3 to 6 months at a time in a steel tube, I know it would not have been too bad for an officer but still. My hat is off to you and to all those willing and able to protect us fat lazy slobs on land from the evils in the world. It takes a VERY special individual to accept this kind of risk for so little reward and even less recognition.

As I would expect, your analysis above, nail meet hammer.

ThisIsLivin

They do make crossovers with a bypass so you can run a thermostat. That's what I have on my boat and it works great.

mike tkach

iTrader: (3)

yes,i forgot about those,i guess the point i was trying to make was the increase in pressure when the flow sees restiance,i have seen the crossover with the fitting & a hose going above the thermostat,looks like it does 2 things,provides water to exhaust system while thernostat is closed,and relieves pressure ,glad you mentioned it.

US1 Fountain

iTrader: (1)

I'm not your friend, but I had the same problem on my stock 502's. Pressure so high the hoses where bulging out.
This is with the 'newer' 2 hose t-stat housing design. I also had to install the Merc relief valves to bring the pressure down. Kinda makes you wonder why Merc make relief valves, eh?

My previous boat had the older, 4 hose t-stat housing with the brass tee. That setup was fool proof and perfect.
Leave it to Merc to take a working system, and screw it up.
When I ran the blower on this boat, with cross over, I had nothing but trouble getting both WP and temps (both water and oil) dialed in.

MILD THUNDER

iTrader: (3)

WTF. I was talking about you! I see how it is