Volvo Automatics for Marine Power.

[FAST FRED]

"The only concern seem to be the fire risk from the exhaust manifold before the water injection system is fitted."

There are commercial exhaust wraps that can tame the heat from the dry section of the manifold.

Why not go all the way and use a dry exhaust , and even a keel cooler ?

No winterizing , no added water pump , and auto quiet with a good muffler.

FAST FRED

[Jango]

Pericles,

I wasn't suggesting using a V8, only pointing out that the Volvo 3.0 weight could be significant if placed too far forward in a 15' boat.

If you are considering going to 23', you should have little problems. In fact, It may be advantageous with a 15 or 16 deg. angle, rather than a lesser angle, since the engine would be higher in the boat, which could help exhaust heat removal and Engine cooling.

Jango

[fasteddy]

I wouldn't do it. The tranny even in manumatic mode relies on throttle valve pressure and governor pressure to select shifts AND band/clutch/brake clamping forces. A two speed GM powerglide from a drag car suppplier would be my only a/t choice. Remember you have to supply cooling to the a/t fluid, too, so another heat exchanger is needed for that purpose alone. Turbos also make a LOT of engine compartment heat, and would require heat shield wrap and triple layer (steel-insulator-steel) heat shields, and you'd have to wrap the exhaust up to the point of water injection, too. Drag powerglides can be built with clutches instead of torque converters, I think, which would make life easier, but you'd still need a cooler.

The stall test for an a/t noted above is not relevant to this discussion, unless your prop is jammed immovable. However, trailer towing stress is most applicable, unless you figure out a lockup torque converter or clutch it, as the slippage loss in the TC makes a lot of heat, and it slips a lot under continual high hp-high load conditions. Do the math to convert 5% of engine output to heat and see what you get. It's scary. Over 38000btu/hr at 300hp. I think the engine compartment would stay dry....

While I'm a little iffy on prop selection, I'd think that if you propped it for high gear, you'd get a double sinusoidal curve in acceleration, instead of one clean pull from rest.

[Frosty]

[quote=fasteddy;117565
The stall test for an a/t noted above is not relevant to this discussion, unless your prop is jammed immovable. [/QUOTE]

My point was to demostrate how much heat is generated from a torque convertor.

How could you prop for anything else but top gear??

[cudashark]

Dear Pericles,

I'm building a replica of a riva design modified to fit Volvo stern drives and in a 33ft design. I have CAD files avalible....

cudashark@adelphia.net

[Pericles]

Hello Cudashark,

Thanks for your post. Will your Riva look something like these boats built in Norway? http://www.dolvik.com/boats.htm

Whilst Volvo I/O drives are pretty good the props can chop up manatees and swimmers! How about a JetPac? http://www.swordmarine.com/

Regards,

Pericles

[cudashark]

Well Pericles,

The boats in Norway have a Riva Aquarama look but to my eye they seem skimpy somehow and I don't think that their are manattees in Norway.

If you want a set of Cad drawings to play with e-mail me at cudashark@adelphia.net

Ray

[Pericles]

True Cudashark,

No manatees in Norway, but you are in South Florida.


Did you look at the Jetpac?

These are the 200hp diesel economy figures from their CD. They used a RIB that looks to be a 30 footer.

2 persons , light gear. Cruising 25.5 mph 6 mpg. WOT 39.6 mph 3.53 mpg.
As above + 1000lbs. Cruising 22.3 mph 5.19 mpg. WOT 34.1 mpg 3.04 mpg.

Weight Time to plane
Stern Console
500lbs 500lbs 5 secs 34.1 mph

1000lbs 3 secs 32 mph

1000lbs 19 secs 37.1 mph

5 persons light gear, 2000lbs sandbags full tank estimated weight 3400lbs

WOT 29 mph 2.64 mph

Fuel consumption at no wake speed 0.3 gph WOT 11.2 mpg

A stitch and glue 33 footer using marine ply and epoxy 1/2" bottom and 3/8" hull sides should come in around 1800lbs with an 8' beam. That's light and very strong and 200hp should push the boat to 45-50 mph WOT consuming around 3.5 mpg. I reckon mounting the Jetpac is much easier than installing stern drives.

Regards,

Pericles