BB marine
Well-known member
- Joined
- Feb 1, 2016
- Messages
- 2,905
- Fluid Motion Model
- R-21
- Non-Fluid Motion Model
- Mainship 34 Pilot
- Vessel Name
- PORT-A-GEE
Our 26 Cutwater has always had a bow high attitude. From 2250 RPM the rest of the way up the rpm ranges the bow just rose. Great ride just bow high attitude. When it was just two on board it was ok. Add gear ,cooler and 4 extra people it was really digging a hole at the stern. Full tabs all the time 2250 rpm and up. I never raised the tabs up because of speed loss. I became concerned about taking our extended trip (LOOP) adding extra equipment ,RIB and outboard, portable generator, paddle-board and tools. Extra gear, cooking, clothing, grill, bikes, paper charts the list goes on. Then provisions it all adds up. I wasn't looking for more speed just more control of the trim attitude to maintain the boats designed performance.
My goal was to make modifications that could be reversed if they didn't work. I machined two spacers to drop the trailing edge of the trim tab down an additional 7/8" This puts the trailing edge even with the bottom of the boat (7/8" of the 2 1/2" trim ram travel was above the bottom of the boat, active trim travel was actually 1 5/8") now I have use of the 2 1/2" travel.


Next I spoke with Cutwater about using Bennett Drop fins with the understanding that if it didn't work the fins could be unbolted. I also talked to a technician from Bennett about the application. He ( Oliver) very informative, said that adding drop fins is equivalent to going to the next larger size trim plane. In my case 26 cutwater 12"x12" Trim Plane, add a drop fin =18" X 12". He stated that 18" X 12" is the size trim plane that Bennett recommends for a 26' boat. Another advantage to the Drop fin is less spray when full trim, the fins hold the water in . Thats how they work. They trap the water and that adds lift. I removed both trim planes from the boat so I could drill the mounting hole using a drill press. I used 1/2" 10/24 stainless screws washers and lock nuts and reinstalled on the boat using life caulk polysulfide sealant.


I have logged three sea trials since modifications all showing positive results. My WOT is the same as last year but the bow is down and I can actually over trim. At WOT I can reduce trim and maintain speed. My cruse speed is the same as last year but the bow is down and I am leaving a flatter wake. The difference is I am comparing last year with 2 people and less equipment no bottom paint ( we didn't leave the boat in the water last year). This year I have bottom painted , 8'10" aluminum RIB ,6 hp outboard, 2000watt inverter, 10' paddle board, Catalina Magna grill, approx 300lbs extra weight in interior modifications.One of the sea trials was done with 4 on board.Three in the cockpit Me at the helm. 1/2kt different compared to my delivery sea trial speed.
2017 with modification 1' to 2' seas Lake Michigan
4130 RPM +/- 20 rpm 20 kt +/- 1/2kt. WOT. bow down full tab but I can lift tabs and maintain speed and bow
comes up
3200 RPM 12kt +/- 1/2kt. cruise speed bow down great ride flatter wake full tab
2250 RPM. 7 kt +/- 1/2 kt. full tab boat runs level
We are happy with the modification and feel that it is helping to maintain the designed performance of the boat. I did post some sea trial numbers in another topic on tug nuts (26 cutwater Performance)
Brian Brown
26 Cutwater
PORT-A-GEE
My goal was to make modifications that could be reversed if they didn't work. I machined two spacers to drop the trailing edge of the trim tab down an additional 7/8" This puts the trailing edge even with the bottom of the boat (7/8" of the 2 1/2" trim ram travel was above the bottom of the boat, active trim travel was actually 1 5/8") now I have use of the 2 1/2" travel.
Next I spoke with Cutwater about using Bennett Drop fins with the understanding that if it didn't work the fins could be unbolted. I also talked to a technician from Bennett about the application. He ( Oliver) very informative, said that adding drop fins is equivalent to going to the next larger size trim plane. In my case 26 cutwater 12"x12" Trim Plane, add a drop fin =18" X 12". He stated that 18" X 12" is the size trim plane that Bennett recommends for a 26' boat. Another advantage to the Drop fin is less spray when full trim, the fins hold the water in . Thats how they work. They trap the water and that adds lift. I removed both trim planes from the boat so I could drill the mounting hole using a drill press. I used 1/2" 10/24 stainless screws washers and lock nuts and reinstalled on the boat using life caulk polysulfide sealant.
I have logged three sea trials since modifications all showing positive results. My WOT is the same as last year but the bow is down and I can actually over trim. At WOT I can reduce trim and maintain speed. My cruse speed is the same as last year but the bow is down and I am leaving a flatter wake. The difference is I am comparing last year with 2 people and less equipment no bottom paint ( we didn't leave the boat in the water last year). This year I have bottom painted , 8'10" aluminum RIB ,6 hp outboard, 2000watt inverter, 10' paddle board, Catalina Magna grill, approx 300lbs extra weight in interior modifications.One of the sea trials was done with 4 on board.Three in the cockpit Me at the helm. 1/2kt different compared to my delivery sea trial speed.
2017 with modification 1' to 2' seas Lake Michigan
4130 RPM +/- 20 rpm 20 kt +/- 1/2kt. WOT. bow down full tab but I can lift tabs and maintain speed and bow
comes up
3200 RPM 12kt +/- 1/2kt. cruise speed bow down great ride flatter wake full tab
2250 RPM. 7 kt +/- 1/2 kt. full tab boat runs level
We are happy with the modification and feel that it is helping to maintain the designed performance of the boat. I did post some sea trial numbers in another topic on tug nuts (26 cutwater Performance)
Brian Brown
26 Cutwater
PORT-A-GEE