25 seafari questions - Page 2

Fr. Frank · #11 08-28-2009, 07:44 PM

Quote:

In my mind, displacement should be the gross weight.
Are the terms different on the water

Brandon

I don't know how anything else is weighed. The USCG lists the net weight of a vessel as the weight of the volume of water the vessel displaces as loaded. It is mathematically the same as the vessel's displacement. But as water density can vary, the net weight can change, whereas the calculated displacement remains the same. Displacement is always calculated against fresh water at 59* Fahrenheit. (I don't know why it's calculated that way, but it's the same temperature used as a base when calculating "density altitude" in flying.

At any rate, the net weight of a vessel is the weight of the volume of water it displaces at current loading at rest in current waters. Manufacturers who use net weight for statistical purposes assume maximum loading in fresh water at 59*.

Just make things confusing, the volume of water displaced must actually weigh LESS than the actual weight of the vessel. The difference in weight is called "buoyancy"

Manufacturers generally calculate a vessel's "dry weight". This is the weight of the hull and structural fixtures when dry. It does NOT include the weight of a power-plant, fuel, cushions, seats (unless molded as part of the liner or cap), etcetera, or any optional equipment.

eggsuckindog · #12 08-28-2009, 08:03 PM

If that was a 23T which I think it is - they are really 25, the cheater boats for the Kingfish guys like a Contender 23T

cdavisdb · #13 08-28-2009, 09:51 PM

Found a 1965 Formula catalog that showed the 233 at 4200 lb. That was the original mold and they put a whole lot of glass in it. I have seen other quotes at 4100 lb for later years. That is dry with engine. My old Seabird 24 was 3900 lb with a 350 outdrive. Subtract the engine and around 3000 lb seems reasonable for those boats. The 25 has more weight up high than the Seabird and is 1.4 ft longer. My 25 seems more solid than the Seabird and some heavier overall, but that's just my impression, have not weighed it. Still, 3000 doesn't seem too far off.

Connor

Blue_Heron · #14 08-29-2009, 01:20 AM

nuthinfancy,
I think Fr. Frank's numbers are pretty close for the 25 seafari. 6000-6500lb give or take sounds about right with power, fuel, crew, and gear. I thought about dragging mine to a scale, but I haven't done that yet. Don't know the trailer weight and don't want to launch it in its current condition just to weigh the trailer.

But... Weight is one thing, weight distribution is another.

From what I've read on this site, and from communication with other owners of 25 seafaris, I think you should look long and hard at your decision to go with a bracket and outboard. The 25 seafari, in its original configuration, has a center of gravity that is high, and pretty far aft. That's why some seafari 25 owners have found ballast under the cabin floor, placed there by previous owners. It's also part of the reason Carl Moesly designed his patented automatic ballast tank system for the 25. If you replace the I/O with a bracketted outboard, the CG will move even higher and further aft.

As an example, CSC member Bigfluke owns three of these boats. One has been converted to a center console, but still has a big block I/O. Bigfluke is a marine architect, and his company in Hawaii has developed an unmanned vessel for the DOD based on the 25 Seafari hull. He says the 25 seafari is the most seakindly hull of its size he's ever run. Of the three 25s he's got, he has said the CC has the best ride because the conversion moved the center of gravity forward and down. It would be worth your time to read through his posts and maybe contact him to discuss the ideal weight distribution for this hull.

Sorry if I sound like a know it all. After all, you've owned and run your 25 for years, and I haven't even had mine in the water. But based on what I've read, I plan to replace the 270 HP carbed 350 I/O with a 300-350hp MPI I/O package motor and keep all added weight as low and as far forward as possible.

Whatever you decide to do, good luck with the repower.

Dave

cdavisdb · #15 08-29-2009, 02:34 PM

Just to reinforce the center of gravity issue. I just got a 1972 25 seafari/ 5.7 volvo duoprop after owning a 24 seabird, with the same power, for many years. I haven't had it out yet in rolly weather, but just riding around the bay, its very obvious that the center of gravity is much higher than the seabird. The seafari is also much more "tippy" while in motion, its noticeable. At rest, the flat hull sections near the stern seem to damp out the roll pretty quick, but that's just based on a few boat wakes, not a good test. Overall, I'm with Blue Heron, raising the CIG further with an outboard doesn't sound like a good idea.

Interesting comparison: At cruise,3300 rpm, the seabird with stainless props is only about .6 knot faster than the seafari with aluminum props.

Connor

seafari25 · #16 08-29-2009, 04:31 PM

Quote:

I don't know how anything else is weighed. The USCG lists the net weight of a vessel as the weight of the volume of water the vessel displaces as loaded. It is mathematically the same as the vessel's displacement. But as water density can vary, the net weight can change, whereas the calculated displacement remains the same. Displacement is always calculated against fresh water at 59* Fahrenheit. (I don't know why it's calculated that way, but it's the same temperature used as a base when calculating "density altitude" in flying.

That makes sense to me, it was just the word net being used for an entire weight that conused me. I`ve read that the same boat will float higher in salt water than in fresh. That`s interesting...I`d like to test that theory one day.

I`m in agreement with the recomendations of Dave and Connor but I`m pretty sure nuthinfancy is set on a bracket and outboard. I believe it can be done if done right. Hopefully Strick will chime in as he`s really done his homework on this topic.

stumpie2 · #17 08-30-2009, 02:27 AM

yeah shes gettin the outboard and bracket.. im just getting my numbers right and weight distribution right.. measure twice and cut once type deal.. im already knee deep into this and imma go the whole nine yards. my original idea was move the cabin door to the port side (toilet removed 2yrs ago due to coast guard issues with no holding tank) and go center steer with a carolina style helm pod,express type deal, and cooler/bench seats along the sides. but vision might be an issue with the windshield seam in the center. if the sceptre windshield will fit that might solve that.. getting rid of the two 50 gal tank and putting single large one further forward... just playing with ideas

nestorpr · #18 08-31-2009, 02:42 PM

My Anacapri Holiday 25 (similar to the Seafari 25 style) with a 350 cubic inch V8 outdrive has a net dry weight of 4000 lbs and the Holiday V-250 (same boat but set for outboard power) is 3700 lbs without power and dry. And these boats have a very thick bottom layup so they compare favorably with the 25 Seafari.

castalot · #19 08-31-2009, 09:06 PM

i had a 1999 proline 251wa it had a dry weight of 4200lbs and it was all of that outfitted with motor and fuel plus extras i figured it about 7000lbs

stumpie2 · #20 08-31-2009, 10:34 PM

castalot, what type of power did you have behind that 251 proline. theres a guy at the marina that i worked and kept the boat at that had one with hard top and curtains powered by a SINGLE 250 evinrude ficht. that has flown past me like i was tied to a stump. i think i can get away with single outboard power and still scoot along pretty well.