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#3
11-12-2013, 11:32 PM
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Here it is.
Make sure to move tank forward also. 
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#4
11-12-2013, 11:49 PM
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Quote:
The 19/20' SeaCraft hull is relatively light and extremely efficient, designed in the mid-60's for motors which weighed less than 300 lbs and weren't more than about 100 hp. There aren't many guys around now that remember those original boats, but I was one of them, and those boats had an amazingly soft ride and outstanding performance with those small lightweight motors. Trust me, the guys who hang big heavy motors on these boats today have no idea how badly they've screwed up an elegant, beautifully balanced design! Just because modern overweight 8' wide 20' boats need 200 hp to get decent performance, it doesn't mean that's appropriate for the SeaCraft design that was so far ahead of it's time that it's still out-performing new boats 50 years later! I did a CSC post several years ago on Pro’s & Con’s of brackets you may be interested in. I can no longer find a link to it, so here is the text from a MS Word file that I saved. Feedback from all the CSC guys with bracket experience said it covered all the angles pretty well BRACKET PROS & CONS (Posted 11-16-08) This question comes up often enough that I thought I’d start a new thread, as I had the same questions many of you are probably having. If you’re wondering, after having gone thru this learning experience, would I do it again, the answer is ABSOLUTELY! However, here are a few things you need to think about before you dive into what will no doubt be a more expensive project than just a transom rebuild! Don Herman, PaulB, Snookerd, Briguy, and Captains Chuck & Lloyd, feel free to chime in on anything I’ve missed or otherwise screwed up! (These comments apply to the 20' hull; for a 23, the pro's are the same, but the con's are probably less severe, as the bigger boat should be a little less weight sensitive, although I'd still be careful about running real heavy twins.) PRO’S 1. The biggest advantage of the closed transom/bracket set up is the safety aspect of keeping water out of the boat from a big breaking following sea. Unless you’ve been in that situation, it’s probably hard to put a value on it, but it’s a very big deal to me! 2. It's really nice for diving and it provides more room in the boat since you can eliminate the splashwell. You've essentially increased boat length by whatever the bracket setback dimension is. 3. It also keeps noise and smoke out of the boat, if you’re still running an old carbureted 2-stroke. 4. Improved Performance. Most before & after tests have shown that a bracket adds 2-3 mph in top speed because motor is running in cleaner water, allowing you raise the motor relative to bottom of boat. A similar increase may occur in optimum cruise speed. 5. Improved on-plane trim capability. Maybe it’s just the 25” shaft motor, but an aft shift of the motor increases the lever arm for both weight and thrust loads! Power trim definitely has more effect on running angle than I had with a 20” motor mounted on the transom. CON’S 1. Downsides are it changes the boat balance because you've shifted the weight of the motor aft, which moves the boat CG aft, and tends to hurt ride and increase min planing speed. On the 20' hull, the Seafari is less stern heavy than the cc models, so it's a better candidate for a bracket IMHO. 2. Low speed maneuverability will be slightly affected, because you've also shifted the boat's pivot point aft. In my own case, I found that the new Seastar hydraulic steering system had a shorter stroke than my old Hyanautic/home-made rig, so it doesn’t turn the motor all the way to the stops, which exaggerated the maneuverability problem. As near as I can tell, all the factory made hydraulic systems have the same stroke, and I haven’t figured out a fix to that yet. 3. You'll have to move the axle on your trailer back a couple feet to keep enough weight on the tongue. 4. All brackets I know of are made for a 25" shaft motor, which might be an issue if you're not repowering or having a bracket custom made. The higher that powerhead is from the water, the better! A few key things you need to pay attention to if you add a bracket: 1. Motor weight! Because of the CG issue, lighter is better! I would not consider the 450-500 lb 150 4S Yamaha, Honda & 150/175 Zuke, and the big block V-6 200+ hp 2 strokes because they're so heavy. That leaves the 140 & smaller Zukes, the Merc Optimax, the small block V-4 & V-6 E-Tecs among the new motors, and the earlier small block V-6 2 strokes. If you run offshore a lot, LESS (power & weight) is MORE. The light 20' hull will start to go airborne at about 20 kts in seas over about 3', so you don't need a big motor for that type of operation. I considered the 375 lb V-4 E-Tec rated at 115 hp (really about 120-125hp) but they weren't in production yet when I bought mine. I’m obviously not a speed demon, but the 150 (really 165) E-Tec at 429 lbs is overkill on power (will run almost 50 mph in flat water) and is the heaviest motor I'd consider. That said, it IS nice to be able to cruise at 4000 rpm/30-35 mph AND carry on a normal conversation! (It’s quieter than the 4-strokes at that speed.) It’s also nice to be able to outrun a thunderstorm if you screw up and get surprised by one! 2. Look for a bracket with the biggest flotation tank you can find, either a Hermco or an Armstrong designed for twins (but use a single on it). Reason is to maintain some self-bailing capability. My rig is still self-bailing, but just barely; I leave the scupper plugs in and depend on the bilge pump if I leave it in the water overnight. 3. Try to run the smallest setback you can with the motor you’re using. I could get away with 18”, so 30” on the Hermco is overkill, although nice for diving! (Don can make his bracket with various setback dimensions.) Making a custom bracket like Strick & Big Shrimpin did is a good idea if you have those kind of skills! 4. You will probably want to run trim tabs, a 4-blade stern lifting prop and maybe a Doelfin or equivalent to maintain good low speed (12-13 mph) planing capability for rough water operation. The flotation tank doesn’t help when you’re on plane, so all this stuff helps compensate for the weight shift. 5. If you already have hydraulic steering, all you need is new hoses, throttle and shift cables that are about 6' longer, at least if you rig them like Don Herman recommends, where everything runs down into the bracket and then thru the transom inside the flotation tank to keep a nice clean transom. If you have cable steering, you'll want to switch to hydraulic steering, which I'd recommend even if you don't go with a bracket. These are just some thoughts based on my own experience. A lot of folks are probably trying to make this decision, so you other guys with brackets, feel free to chime in! Denny
__________________
'72 SeaFari/150E-Tec/Hermco Bracket, owned since 1975. http://i188.photobucket.com/albums/z...Part2019-1.jpg
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#5
11-13-2013, 12:39 AM
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Denny, Denny, Denny.......
 Sometimes you just wear me out! Having an engineering background myself, I took the CG into consideration when the NoBones was rehabbed 20+ years ago. Simply moved the console forward and the 80 gallon tank forward to maintain the CG with a 200HP carbed Merc hanging on her butt!! She has performed effortlessly since! Yes, sometimes logic works with science!! Ok, I feel better now...  We still love you Denny! 
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See ya, Ken ©
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#6
11-13-2013, 11:35 AM
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Welcome Dave, a lot of good info on this site, mill around and see what you can find.
When you get it all set up you can do mine at the same time. LOL
__________________
May all your deadrise be variable. My 1973 SeaCraft 20SF Parker 2530 DVEC Boston Whaler 15 1984
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#7
11-13-2013, 12:11 PM
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I will also add if you do the floor, make it level all the way to the bow. If you need, build you a coffin in front of the console or just fasten a good size cooler in front.
This boat had flush mounted brackets to mount the cooler for offshore trips. This boat has been 60 miles offshore in some pretty tough stuff and the ride is awesome. No CG issues at all. I think it actually rides better than the original. Big @ss trim tabs when needed.
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#8
11-13-2013, 03:53 PM
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Quote:
Sorry for the long post . . . I would have much preferred to have just used a link to that old thread - thought it contained some useful info for a new guy. Do you have any idea why I can no longer find it with the search function? Did we lose a bunch of old material when we switched over to the new web site host? Denny
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'72 SeaFari/150E-Tec/Hermco Bracket, owned since 1975. http://i188.photobucket.com/albums/z...Part2019-1.jpg
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#9
11-13-2013, 10:17 PM
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Quote:
__________________
Snookerd
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Hybrid Mode
