Bracket on a 20 MA questions

jorgeinmiami · #1 11-15-2009, 11:38 AM

Yesterday I saw a boat that is just like mine in my neigborhood. It went to fill up at the gas station that I was going to.
I looked it over and it got me thinking.
I am shopping for an engine and it seems that the majority of the engines come in 25" shafts. That would leave me with options of redoing the trasom to get to the 25".
This one had a bracket on the back with a 25"engine.
My question is would this be a good option? Would the ride be ok or would it upset the balance? Also I think it would be a quicker project than tearing up the transom and it would add a nice platform for swiming

Here is a pic of the other boat

What do you guys think?

stumpie2 · #2 11-15-2009, 11:44 AM

close the transom and add the bracket. will make the boat safer and add cockpit space. should also improve performance numbers

Bushwacker · #3 11-15-2009, 02:46 PM

Quote:

Would the ride be ok or would it upset the balance? Also I think it would be a quicker project than tearing up the transom and it would add a nice platform for swiming

What do you guys think?

It WILL upset the balance and tend to hurt the ride, but there are ways to compensate for that. (Search for my post on pros and cons of brackets) Here's what I'd recommend, based on my experience with a Seafari, which is less stern heavy than any of the cc models:

1. Use a bracket with biggest flotation tub you can find (a Hermco!) to maintain self bailing. Use the smallest setback you can live with. (Don can make 18, 24 and 30" versions.) I went with 30" model because I do a lot of diving, and it's great for that.
2. Use the lightest motor you can find that provides enough power for what you want to do. This eliminates all the 4-strokes except maybe the Zuke 140 and smaller. I ran mine for over 30 years with an old 300 lb 90 hp (at the prop) V-4 and it rode great. I run mostly offshore, and you can't run much over 20 kts in the 20' hull without going airborne if there is any sea running anyway. Don't run much faster with the 150, but I now have a lot of margin for heavy loads.
3. Plan on running a 4 blade prop to get more stern lift. Trim tabs and a doelfin or equivalent will also help. For some reason, maybe the 25" shaft or added leverage with the bracket, power trim is much more effective with current rig than it was with a 20" motor on transom, which will partially offset the rearward shift in CG. My original rig would plane at 12 mph, which is nice when it gets sloppy. Could not do that with new rig till I went to a 4B prop! Denny

pl99 · #4 11-15-2009, 04:00 PM

Quicker project huh? I do not think it would upset the ride much to install a bracket... I had my transom low for years with three different outboards.. I went from a 200 black max, 250 merc 98 to 03 honda225. Was Always wet and stiil had a silky smooth ride and yes was stern heavy. <RAISING TRANSOM IS WORTH IT>

If you llike to get wet when its rough then keep it low, U just get less wet with it raised.

Love my Platform and Raised transom. Not much difference in ride that I noticed.. Well maybe JUST a little.

Yu gott a Million Options Bud.. have a good week

pl99 · #5 11-15-2009, 04:02 PM

PS you got a wealth of information at your fingertips in the older threads..<postings>

jorgeinmiami · #6 11-15-2009, 04:11 PM

If I go with the bracket I would like a 150 Merc Opti or Yami 150
I would move the batteries up under the console amd what ever else I could.
I think I would leave the motor well open (like in the picture) and I have the original spash well so it should keep out water and if I was just going to swiming and barbeque and such I could take it out.

But sounds like either way would work if I can find a 20" shaft engine in good shape.

Another Idea would be to get a "in-between engine" till I redue the transom to 25"
Thanks for the input

workinpr0gress · #7 11-15-2009, 06:41 PM

I have 400 lb. 25" old crossflow v6 with a 3 blade 15x17 prop on a 30" Armstrong on a 20' with no tabs and just a foil. I don't need tabs or a stern lifting prop. My batteries are under the console. My cockpit is just barely self draining on the original floor. I believe the ride is superior in a sea to without the bracket. Not to mention it alleviates a ton of spray that SeaCrafts are known for. Me personally I like having a little more weight towards the back to a point. The bow tends to stay in the air wave to wave much better. The trimability to nose the boat in or run on the last five feet is great. And it's especially nice to run a boat from the Sweet Spot of the boat. I havn't been on to many boats that don't run better (looser, tighter, drier, faster, smoother) with a bracket as long as someone doesnt get crazy.

I used to work on a 57' Monterey (one of the best riding coldmolded speedsters ever made) and used to fish on the sister boat to the one I worked on. The boats were identical except the engines were a foot further back and 75% of the fuel and genset were in the cockpit and no trim tabs on the one I worked. As opposed to the sister boat carried it's fuel forward and had the genset in the engine room and the gear further forward and had tabs. The boats burned 8 gph different and were 2 knots different at the same rpm, the sister boat would soak you to the tower on a 4-6 head sea and pound pretty good for a Jim Smith style hull, the other would get the back corners of the covering boards wet and the tips of the outriggers would barely move. I am for moving as much weight back as possible for the most part while still keeping a margin for safety. It doesn't work for every boat but enough other people have done these things at this point you should be able to figure out how ya wanna go. good luck

zach · #8 11-17-2009, 07:27 PM

I've really enjoyed the bracket on my boat. I've been running it about a year and have around 100 hours on her. The bracket is great and I wouldn't change a thing. Here is my thread from when I got the boat.

http://www.classicseacraft.com/forum...=&fpart=1&vc=1

Bushwacker · #9 11-18-2009, 01:41 AM

Quote:

. . I think I would leave the motor well open (like in the picture) and I have the original spash well so it should keep out water and if I was just going to swiming and barbeque and such I could take it out.

But sounds like either way would work if I can find a 20" shaft engine in good shape...

I would not put a 20" motor on a bracket; powerhead will be too close to the water. Get a 5" extension kit instead like Fred H did on his. I think they're available for most motors.

One advantage I noticed with bracket is that it increases your trim range. It shifts CG aft so it's pretty easy to get a lot of the bow out of the water; can probably pick up 2-3 mph top end that way. I can run almost 50 mph with top down and full tank of gas with just me in the boat. However the longer shaft and/or leverage of the bracket seems to make the power trim much more effective at controlling running angle, so I can also trim the bow down and plane at 12 mph for a soft ride in rough seas. I just use the tabs for lateral trim and adjust running angle with engine trim.

Hermco has a version of the bracket with just a covering board for the cutout which you could use to avoid filling the transom. Here's a shot of the Hermco bracket with the big flotation tub plus a couple of ideas for what you can do with the splashwell.

eggsuckindog · #10 11-19-2009, 12:32 AM

Here's my take - use a 25" motor to keep the PH higher away from the water as BW stated - you could leave the notch in the transom just use a fold down transom door - kinda like the 23 Sceptre has on top of the splashwell - would make entering and exit easier.

Go to Scream & Fly - tons of parts avaiable over there and lots of 20" motors and mid's cheap. Most have no use for stock mid's so there cheap and use a drop on PH maybe. I ran into the same issue, 20" motors are hard to find in the pleasure arena but 20" mids over there are cheap