Question on Prop Size For 1979 F44 and Cruise Speed

[Lean Wolf]

I recently purchased a 1979 F44 with twin Detroit Diesel 671 naturals in it. The props that are on it are 24x24's, there is a set in the bilge and I have not looked at the size of them. The old owners (family members) think they put the spares on and the originals are in the bilge. Does anyone know what the original size was that came with the boat? Does anyone know what top end and cruise speed should be? I remember years ago the boat going on plane and running maybe 17 knots at WOT and I think that was with the props that are in the bilge? Now it won't get on plane and is running 12 knots at WOT. The port motor is running 2500 RPM's and the starboard is running 2375 so it needs some tuning. I just purchased the boat 2 months ago and am going to completely renovate the boat and need to start with the running gear. Any words of wisdom on this would be sincerely appreciated!!
Drew

[prowlersfish]

Is the bottom clean ? running gear ect,

[summer storm]

Hi and welcome to the forum,

In 1977 the sea trials provided the following data.

F-44 factory boat with J &T 6-71's 310 hp at 2500 RPM 2:1 reduction

4 blade 24 X 24 props

18 MPH @ 2,300 RPM

21 MPH @ WOT

213 mile range at cruise using the 320 gallon fuel capacity

168 mile range at WOT

I hope that helps

[aaronbocknek]

hi drew, welcome to the forum. the f-44 is a really nice vessel. i'm curious. does your particular model have the 'trojan underwater exhaust system'? while i know that trojan did not invent the underwater system, the design to trojans, at least in respect to the tri cabins of 1977-1987, is a unique set up. just curious. would love to see some pics of her, and the exhaust system.
thanks for your help.
tri cabin aaron, baltimore, md.

[Lean Wolf]

Powerfish-Yes, the bottom was cleaned and painted this summer and the running gear is in tact. I ran the boat right after the bottom was painted and it was still only running 9 knots at cruise and 12 at WOT.

Doug-Thank you for the data, that is exactly what I am looking for. Not sure what my issue is, maybe the 24 x 24 props on there have been pitched down for some reason. The boat is seeing close to the RPM's you referenced and I am not seeing that speed anymore. I am having my mechanic adjust the valves, injector timing etc this winter so hopefully that will help a little but I think I have a prop issue, there is simply too much variance in speed from the data you have given me.

[Lean Wolf]

Aaron,
The boat has a typical through hull setup that exits at the water line. The port side riser actually has a leak in it so I need to try to track down another riser or will have this one repaired (hopefully not re-manufactured) over the winter. Any ideas on where to come up with a riser?
Drew

[Lean Wolf]

Trojan s.JPG (112.43 KiB) Viewed 7195 times

Attached is a picture of the boat.

[aaronbocknek]

Aaron,
The boat has a typical through hull setup that exits at the water line. The port side riser actually has a leak in it so I need to try to track down another riser or will have this one repaired (hopefully not re-manufactured) over the winter. Any ideas on where to come up with a riser?
Drew

so all exhaust gas/water exits at the hull side port and starboard or transom? are the mufflers inline or lift? as for risers, osco is usually a good source.

http://www.oscomotors.com/

[prowlersfish]

Nice Boat .

I don't belive you will see the speeds Doug listed The 2 F40s I know with the same engines don't run that fast . But with that said I do belive you should be much faster the you are .

[Lean Wolf]

I am not sure whether the mufflers are considered inline or lift. They are located under the cabinetry in the aft cabin. The risers and elbows snake through the engine room, into the aft cabin where the mufflers are and out through the transom.

[prowlersfish]

Do you happen to have the weight of your boat ? I can run it on the boat diesel cacl.

[aaronbocknek]

drew, thanks for the portside pic. she is beautiful. so she was the family boat and passed onto you? where do you keep her?
sorry i'm so long winded tonight.

[Lean Wolf]

Prowlerfish-that would be great, thank you for your help. The boat weights 32000 lbs.
Drew

[Lean Wolf]

Aaron,
I keep her on the Sassafras at Sassafras Harbor Marina. She was my fathers boat for the last 13 years, I have been running and maintaining it for him for the last 5 years and I just bought it from him. I just ran it to Croydon on the Delaware River last weekend, she is coming out of the water and I am going to completely renovate and update her this winter.

[aaronbocknek]

nice to see her stay in the family. i'd love to take a road trip up your way in the winter to check her out. hey, i can even lend a hand if necessary.
aaron