What motor size can i use ?

[cadeco]

Originally Posted by hermco

Get a bracket designed for a 20" shaft motor. The bracket geometry/design determines the shaft length of the motor. Most are designed for 25" shaft length motors. You might be able to use some brackets designed for 25" shaft motors with a 20" shaft motor if you can mount the bracket low enough. Depends on the brackets design.

Thanks for the input, but the idea is this : Since using a 25" motor on a normal ( made for a 25 ") bracket, the 25" motor must be raised, using a 20" motor on that bracket would be ok and the 20" would not need to be raised-- correct?--
If i use a normal 25" bracket today and latter i change the motor , the only thing to do would be to raise that (new 25") motor instead of buying a new bracket. If i have to use a 20" bracket there will be no deal!--Someone says to install a extension (if does not work), but the cost of the extension will offset any gains on the 20" motor's price.
Again thanks! think about and tell me where i'm wrong ( if i am).

[Bushwacker]

I rechecked current AV plate height today and it's 3.75" above keel, not quite as high as I thought. The pic I got isn't real clear (couldn't find my old white plastic scale); the metric side of the scale is actually more readable than the english units . . . the 9.5" cm measurement converts to about 3.75". The AV plate is still underwater when on plane; my guess is that it needs to be raised to at least 4.0 to 4.25" via a jackplate or spacer. The middle pic was taken before Don redrilled the mounting holes to raise the motor and last pic was taken after raising. The most obvious difference is the position of the lower bolt relative to the 2" tall bootstripe.

My 25" motor is currently mounted as high as it will go. I need to check hole spacing on motor bracket to determine total height adjustment available, but I suspect a 20" shaft motor might actually work if you mount it as low as possible with bracket mounted at height Don recommends, and with mount bolts positioned in top holes so you can raise it if necessary. although you will have to decide if you can live with the powerhead relatively close to the water!

[dave s]

Although not SeaCrafts, my buddy and I have 25' Contenders, and have a similar situation as you.
We both run a single 225 Yamaha four stroke on the original double floatation bracket setup for twin motors; didn't move the brackets.
Mine is a 30" leg and his is 25"; I had to raise my motor as high as it'd go and even added a small jackplate- raised it two inches and the AV plate is still buried. I can raise it even more.
His motor is as low as it'll go but it will cavitate occasionally, usually when it's rough or if he trims up too much.

If you stick with the 20" motor, it'll probably work, but you may want to lower the bracket also.
If you going to repower with a 25" later, then set the bracket higher now.

[cadeco]

Thanks to both of you. I guess I will go w/ a regular (made and installed for a 25"), get the 20" and use it low,. After all boat be done I will re power it w/a normal(sic) 25".

Bushwacker, I liked ( in fact I loved) see the bracket on yours. I just can't explin to my wife the act of buying a bracket (Hermco) over $1000,00 above the price of a close competitor. If prices were closer i would go w/ them , but money is a bit on the short side . Thanks for the photos and response.
That's why this site is soo goooooood!!!

[Bushwacker]

Don does charge a premium for his bracket, but if you boat in salt water, there's something to be said for never having to worry about corrosion on it! Plus the fact that it has a lot more flotation than any other bracket, which allows my boat to still be self bailing at the dock with a relatively heavy modern motor. With a different bracket, I'd have to raise the deck to get that capability, so if I factored in the cost of ripping up and replacing a perfectly solid original deck, the cost premium becomes insignificant!

Another option I recommend that anyone consider that's planning to install a bracket, or even a heavy 4-stroke motor on the transom, is to also move the console, batteries and gas tank forward to offset the CG shift that will otherwise occur! That will also help the self bailing issue and possibly eliminate the need for a 4B prop and fin to maintain a low planing speed and good ride. I didn't have that option since the Seafari has no console and I didn't want to eliminate the large stepdown in the cockpit required to move the gas tank and batteries. However the Seafari also has more weight forward than the CC to begin with, and the large cabin makes it easy to load lots of gear up front, so the Hermco bracket has proven to be a great solution to the low transom and space issues I wanted to address.

[cadeco]

I would like to have a Hermco due to being fiberglass ( and i believe looks much better), but i don't know how it can give better flotation since most "flotation" brackets follow the same basic design. At the end is all about money!!!

[Bushwacker]

Originally Posted by cadeco

. . . but i don't know how it can give better flotation since most "flotation" brackets follow the same basic design.

better flotation = larger volume flotation tank! The difference is in the details - look at mine closely and you'll see that bracket extends straight back from the transom instead of sloping up as most others do, so it's displaces more water back at the motor mount surface. The sloped bottom on other brackets was evidently done to avoid contact with the water when going on or off plane, but I think this is a mistake. The ideal bracket would simply extend the bottom of the hull further aft to get more planing surface, and Don's bracket is the next best thing, since bottom of it is only about 3" above the keel and deadrise matches that of the center panel, so it can act much like a hull extension/trim tab as you're coming up on plane. The Hermco flotation tank also appears to be wider than that of other brackets, and Don has talked about making it even wider, out to the second step, to accommodate the heavier 4-stroke motors. He said Potter sized the tank to allow room to install a folding ladder underneath the swim platform, but his experience is that few people install ladders, so an even wider tank would be a logical option, given the popularity of the heavy motors.

Nothing really wrong with aluminum brackets other than the corrosion potential, which can probably be minimized with powder coating, and they should be a bit lighter than a glass bracket. Regardless of what bracket you go with, I'd recommend rigging it like Don does for a cleaner looking installation. (Run motor rigging through the transom into the flotation tank and then up through the swim platform instead of just running it across top of swim platform.) The swim platform is much more usable when not cluttered up with rigging!