1973 20' CC Transom woes
 

Thanks in advance for any input on this.

I've taken temporary possession of my dad's 1973 20' CC. I was planning on using it on Lake Anna, VA, pulling a wakeboard, as well as some fishing on Sinepuxant Bay/Chincoteague, VA. I've now been told I need a new transom.

The boat was purchased 18 months ago for $8k, on a 2002 Continental tandem trailer, and in December 2010 re-powered with a new (leftover) 2008 Mercury. ($10k)

In trying to find a leak that was filling the boat @ 2gal/15 minutes, I discovered that the area around the 2 lower engine mount bolts is crushed, and the two mounting holes were extensively filled with 3M 5200. Two separate boat repair shops at Lake Anna, VA, and a fiberglas expert in Fredericksburg, VA have advised me that the transom must be replaced. Their proof is that when you lift up on the engine, you can see the transom flexing around the mounting bolts. Also, there are several hollow sounding spots across the entire transom that don't sound like simple gelcoat delamination.

The marine shop in Fredericksburg, VA, has quoted me a price of $3800...YIKES! He replaces the entire transom, edge to edge, with a product called "Coosa", 1 1/2" thick. He would also raise the top edge of the engine cutout so that the Mercury 150 would actually rest on the cutout, instead of floating 3 1/2" above it, the way it is now, with the entire weight of the engine resting on the 4 bolts.

There are no soft spots anywhere on the deck, and all 3 gentlemen commented that it was "a great looking boat", well worth the cost of transom replacement.

Question: My dad has about $20k in the boat already, it has a fabulous T-top, on a 2002 Continental tandem trailer with a new front axle with completely new brake system. He keeps the boat in Bradenton, FL. Should I have my (almost)local guy do the job here, or drag it back to the Bradenton area and have it done there? Who might be a recommended shop (I suppose anywhere in FL) if he decides to have it done there?

Is $3800 a fair price?

Thanks again for any input. My dad owned a 73 Seafari, quickly moved up to a 1974 Tsunami I/O (the 1972-3 [?] O/B Johnson, combined with the deep transom cutout of the Seafari scared him). He sold the Tsunami, mint condition, in 1989 or 1990 in the Va Beach area. We, as a family, love the Seacraft design, but are experiencing, for the first time, the woes of a major rebuilding process.

Thanks again for reading.

Ed in Arlington, VA.

Re: 1973 20' CC Transom woes
 

Hummmmm.......$3800 might be steep. Snookerd might have some contacts in Bradenton. Building the transom up 3'' or so is a good idea. Oh yeah, the engine is supposed to rest on the bolts. If you sit the engine against the top of the transom, where there is no room for vertical adjustment, you would nave to make sure you have it perfect the first time.

Re: 1973 20' CC Transom woes
 

Thanks for the quick response. I'll wait and see if snookerd weighs in...or I'll PM him.

I understand your comment about vertical adjustability. I just find it amusing that the bracket is shaped/designed to "hang" on the cutout, yet almost no new installations do that. Too many variables in cutout height, of course, and only "one size fits all" shaft lengths.

I'm hoping someone will weigh in with an opinion on my description of the transom condition, and the absolute need for new transom vs. digging out the core and filling it with ???

Re: 1973 20' CC Transom woes
 

I did my transom with Arjay. However just "digging out the core" ain't all it's cracked up to be. To go with a ceramic pourable compound there can be no leaks in the inner skin or anywhere. The odds of getting all the old wood and crap out of a 1 1/2" creavace without poking a hole some where is slim. I went with cutting off the transom and cleaning all the way to raw fiberglass, patching all holes and re-attaching the skin. When finished the Arjay it's as hard as can be and will never rot. If you have the transom done with plywood, coosa, whatever the transom still comes off. I'm assuming you have looked a the Hermco site to see how it's done and how much is involved?

Re: 1973 20' CC Transom woes
 

Just looked at the Hermco site. I'd still need a sound transom before installing a bracket, right?
I've never been a fan of the bracket design on such a short boat, as all that weight hung out so far just doesn't make sense to me. Adding trim-tabs into the mix just gets to be too complicated for me.
I'm not thinking too clearly right now anyway, as I borrowed the boat for some leisurely boating/fishing, and it's clear that won't be happening in the next 60 days. Add a 12-year-old boy, 9-year-old girl into the mix, and there's big-time disappointment around here.

I guess I should be happy I've still got the 14' Portabote, 9.9 Nissan. It's a lot of fun, quirky, and a real head-turner as it passes other 14' boats at 18-20 mph. Obviously, it doesn't come close to the 20'CC.

Re: 1973 20' CC Transom woes
 

For around here, thats a pretty fair price. I have no idea on the cost where you are. That being said, you could probably save your self 1000-1500 by doing the demo yourself. That is the most miserable part of doing the job. If you are thinking about a hermco bracket, you will want to raise the transom ALL the way up. The nice parts about the Hermco are the weight, and the floatation tub. These both help to keep the back of the boat UP even with a heavier motor.

My 23, you can see the old outboard cutout and the new rounded top.

http://i612.photobucket.com/albums/t...b/PA111486.jpg

Re: 1973 20' CC Transom woes
 

First off, it is absolutely worth the cost of a transom replacement.

Price is a different matter. $3800 would be top dollar around here, in the FLA panhandle. $2800-$3300 is closer to average cost. I got 5 bids on replacing mine and raising it to 25" in the last 6 weeks. Bid were from $1600 if I de-rigged and did the demolition (including cap removal) and re-rigging later, to $3650 for having the job done start to finish.

Doing the demolition will save you at least $1000, and can be done in about 6 hours if you can do it from the outside, 8 hours if you have to cut off the back of the cap and have an aft livewell.

Re: 1973 20' CC Transom woes
 

Thanks, all, for all the information. After lengthy discussion with my dad, we're going through with the complete replacement of the transom. Unfortunately, we'll have to pay for the whole process, as he's just too old for such labor, and I just can't do such a large job. I'd love to take on the challenge, but, I'm a concert pianist/teacher and at age 57, the rate of recovery for my hands after doing this sort of rough work is just too slow.

Thanks again for all the helpful responses.

Re: 1973 20' CC Transom woes
 

Very wise choice!! Good luck!!! Let us know how it turns out.

Re: 1973 20' CC Transom woes
 

We love pictures! Good luck!

Re: 1973 20' CC Transom woes
 

The plot thickens.
I just found out that this boat had a breach in the hull, on the keel, at the bow, right where the hull cuts into the water. It appears that someone may have run it into a solid object, and then did a quick and dirty repair, painting over it. My dad bought the boat w/o seeing this repair.
So, one year ago, he opened up the place, dug out a good bit of wet wood (on the keel), filled it with fiberglas fabric and resin, and painted over it.

QUESTION: How can we know how much damaged wood is in the keel w/o opening it up, and (properly this time) grinding it until dry wood is found? As this potential problem is 15-16 feet from the transom, how can we know how extensive this rotted wood is?

Impossible question, I presume, but curious if the experienced folk here would consider this new issue to be a "deal breaker" for the transom rebuild, as there may be more structural damage to worry about.

FYI: boat was "re-decked" by a previous owner, and floor appears to be very solid.

I might as well ask, since I have your attention...how high is up?
Thanks again for input. I'm learning a lot here, very quickly, and so far, haven't needlessly spent $$$. Yeah, I know, it's only a matter of time...

Re: 1973 20' CC Transom woes
 

I've seen several where, from over many years of impacting the trailer when loading or beaching the boat the keel is worn straight through to the keelson (the wood). Likely if this is the case, all the wood is rotten, not really a big deal as there is heavy glass over it. The repair is a pretty easy one, grind back (from the outside) to good glass, and re-glass.

Be sure to check in front and behind your trouble areas...for other thin areas.

Re: 1973 20' CC Transom woes
 

Dealing with my 88-year-old dad is stressful, to say the least.

He has decided to have the transom rebuilt in the Bradenton/Sarasota/Ft Myers region, as he wants to be closer to the work being done. In addition, he has decided that $3800 is just too much to put into a 38-year-old boat with an unknown history, and that he can have it done for less in FL.

So, now the question: Any recommendations for a reliable transom rebuilder on the west coast of FL?

Thanks for all the valuable feedback. We're learning as we go, and appreciate all the input here.

Re: 1973 20' CC Transom woes
 

Good luck and take some pics dont let them put wood back in or your back where you started

Re: 1973 20' CC Transom woes
 

i have heard a few good things about these guys. may want to check them out. link

Re: 1973 20' CC Transom woes
 

Yeah boathaus, those guys are good.

Re: 1973 20' CC Transom woes
 

Now I'm getting annoying...but...anyone there in particular that might be partial to Seacrafts?
Thanks. I'll have my brother drive by and check them out.

Re: 1973 20' CC Transom woes
 

www.hermco.net has put more than a few transoms in Seacraft boats, along with brackets. Hes a mod on here too. He is hike away from you though.

Re: 1973 20' CC Transom woes
 

Yes, Hermco is doing my '75 23 cc right now. He has some pics of it on his website under current project.

Re: 1973 20' CC Transom woes
 

I've found a shop in the VA. Bch area (Coastal Fiberglass) to replace the transom, for much less than FL, and I can keep the boat closer to me. (I may not give it back to my 88-year-old dad, for many reasons, some of then quite selfish!) The repair person and I were examining the boat yesterday, and he commented that "No dealer should have hung that motor on there w/o checking the transom. It's in terrible shape", as he tapped and demonstrated that most of it sounded hollow, and showed me how much it all flexed when weight is applied to the motor. He was as disgusted as we are. Curiously, he was able to name the dealer (brand) shop that did it, although his experience with the brand was in the Va Bch area, not Bradenton.

So, while looking at the mounting, he questioned the height of the cavitation plate. Remember, this is a 1973, 20' CC, 450+lb., 150hp Mercury 2-stroke motor. Currently, the cav plate is almost 1" higher than the keel. Is this correct? The transom bracket (the part that LOOKS like it should hang on the cut-out)is about 3 inches higher than the cut-out, and the transom (which must have been replaced) is 25".

Thanks for input. He wants to know where WE want the engine mounted. He has his ideas, but wants our input.

Re: 1973 20' CC Transom woes
 

Are you sure about those measurements?

Re: 1973 20' CC Transom woes
 

Private message sent.

Re: 1973 20' CC Transom woes
 

New transom in place. Mercury OptiMax150 Motor reset so the AC plate is exactly level with the flat of the keel.

MiragePlus 48-18278, 17p prop. Underway, top speed around 40+, 5200rpm.. At top speed, regardless how I trim it, the AC plate is buried (I can't see it, clear water) and I feel the bow is too high when trimmed properly. I'm aware that this motor is 150lbs heavier than the original motor(s) back in the mid-70s, but I expected, at full throttle, things would level out.

Any thoughts? Should I raise the motor a notch? Is this the proper prop for efficiency? I'm surprised how much lateral spray comes off the motor, at speed, unless I tilt the motor out a good bit.

Again, thanks for helping me out with this.

Re: 1973 20' CC Transom woes
 

You should be able to go two holes higher.

Re: 1973 20' CC Transom woes
 

Thanks, Don. You've continued to offer me sound advice. I've just spent an hour reading the "performance" threads re: props and motor height. Wow, do I have a lot to learn!

I think I've got the correct prop, and will raise the motor. There's a Mercury tech where I've got the boat stored, and he's willing to go out with me and check things out, and will raise the motor for me, as well. I might also install the Hydro-Shield I've got sitting in the back of my truck, per Fr. Frank's advice. I've just got to get over the thought of drilling through the skeg of the "new" motor!

Once again, I'm so pleased to have all this knowledge available. Thanks, guys.

Re: 1973 20' CC Transom woes
 

I am happy with my hydro-shield and it has saved my prop from damage at least once this season. I suspect that dragging it thru the water might hurt my top speed, but maybe that is offset by the fact that trim seems great, even with a 4 stroke and a kicker on a 20 footer- about 430 lb total back there. And I am only pushing it with a 100 hp outboard.

Re: 1973 20' CC Transom woes
 

What did you use to seal the holes? Does the bracket gouge the paint enough that sealant needs to be placed around the edges?
Thanks.

Re: 1973 20' CC Transom woes
 

I did nothing. My skeg was already lacking paint from the prior owner. Florida-style.

The button head screws and half height shear nuts are fairly low profile. I just bolted it on, making sure it flies parallel to the anti-cavitation plate, and ran with it. That is a little nerve wracking- the drilling to line it up bit.

But it is on now. I bent it a little to conform to the skeg a bit better- I made the vertical parts a tiny bit concave so the leading and trailing edges squeeze tight against the skeg. I grounded it once and it has held up well, despite the fact that the 3 screws don't look that huge. I have the size large on my 100 hp 4 stroke Yamaha, for what that is worth. And the grey matches well.

I would either paint the whole thing afterwards if you want, or you could bend the stainless bracket carefully as I described and sand or grind it to conform to the skeg nicely so it doesn't scratch. I didn't see much of a gap where I could use RTV sealant.

Re: 1973 20' CC Transom woes
 

I noticed, when I held it up to the skeg, that the curve of the bracket doesn't follow the lines of the skeg, so I'm sure the top edge would cut into the paint. I'll be sure to flatten the bracket out so it lies flush.

Re: 1973 20' CC Transom woes
 

http://abcPics of mine installed on a previously thrashed skeg. http://i1119.photobucket.com/albums/...ldsideview.jpg

http://i1119.photobucket.com/albums/...0lowerunit.jpg

http://i1119.photobucket.com/albums/...ldrearview.jpg

Re: 1973 20' CC Transom woes
 

FINALLY, getting the boat back in the water to check new scupper repair...also to re-evaluate anti-cav plate height.

Another question: I will be installing the Hydro-Shield. Does this change the suggestion that I raise the motor 2 holes, to put the AC plate at 1 1/2" inches about the keel level (Currently AC plate is level with keel...I can't see it while on plane with moderate load). I need to get this right, as I don't have access to easily play with motor height.

73 20' CC, 150 OptiMax (HEAVY), 2 batteries in front of the console, rear baitwell.

Thanks again, folks.

My, how time flies. My schedule and weather just haven't permitted moving forward at a faster pace.

It took some doing, but the tech that I asked to raise the motor kept refusing, as he is afraid I'll bring the boat back to him with an over-heated engine. He couldn't have been more clear with his protestations, and I imagine I'll get an earful when I see him tomorrow. He was reluctant to believe what I have read here, from devoted SC owners.

So, he finally raised the engine (needed to drill 4 new holes, and fill the old ones) so that the anti-cav plate should now be 1 1/2" above the level of the keel (I'll see it for the first time tomorrow, weather permitting).

I'm running a 2008 OptiMax 2-stroke, prop is 15 1/2" , 17P, Mirage Plus, getting 5200rpm at WOT, moderate load. What should I look/listen for during this shake-down cruise? I know the 2008 150hp OptiMax has overheat protection (buzzer, automatic throttle reduction), but I'm just wondering if there's anything else negative to look out for? Might it cavitate more on hard turns, and is occasional cavitation normal when plowing through wake while turning? I'm fully expecting quicker hole-shot, and more level WOT planing, with less lateral spray from the motor. Should I also expect higher top-end speed (currently around 41mph) and higher revs from the engine, as well?

Thanks agains for the help. I hope I've not come off as an insufferable newbie with all my questions.

Do you have a water pressure gage installed? It might give you some warning of cooling water supply issues before it overheats.

Hey Pianewman-

I finally got to look at my setup this weekend in action. With the Yamaha F100 and the size large hydroshield and a full boat (3 guys, 3 tackle boxes, a kicker, kicker fuel tank), it looks like the anti-cav plate was in fact about 0 inches above the keel, running basically dry at about 31 MPH with minimal lateral spray off the lower unit. No tape measure involved, as I was leaning over the transom at WOT.

I also have the two batteries in the center console, along with a 20 gallon topside tank. I have flotation foam where the under deck tank was.

Again, with the noticeable stern lift at WOT from (I suppose) the hydroshield and 4 blade stern lifting 12-3/4 x 17P prop. A hat tip to Fr. Frank for the suggestions on my setup.

I agree that Fr. Frank deserves a "tip of the hat". He's gently told me what to do, over and over...I've got my dad speaking into my other ear, though, and his mid-west stubborness is slowing me down..

FishStretcher...where is your anti-cav plate when at rest, motor all the way in? What's the width of your large Hydro-Shield? I was told they don't make it anymore, and Fr. Frank recommended the medium anyway, because he thinks the large flexes too much?

Any cavitation with directional changes at WOT? I would think ACplate OUT of the water 1 1/2" might create some cooling issues?

Rained out today...upper 40s f...I'm a wimp...fishing should be fun...

The 1 1/2" is correct especially with that prop, I would not put that whatever on in any case but especially before running the boat without it. Can't figure out why the holes had to filled and re-drilled ? should have just raised the motor put the bolts back in

The transom drilled holes were too low, and the engine was already resting in its lowest holes.

No WOT handling issues, it carves turns as hard as I am comfortable with. No cavitation, and 2 weeks ago ran at absolute WOT for ~11 miles at a time (20 minutes) with no high temp alarm. Twice.

I will look for a picture of the anti-cav plate positioning. I might have a picture in my phone.

How much does the 150 weigh compared to my F100 and kicker. Remember, I am lifting ~428 lbs on the stern when I include the kicker.

The OptiMax is around 460, I believe, so I've got you beat, weightwise. I might have a full baitwell, as well, but I've not done that yet.
I trust if the engine gets too hot at WOT, I'll be able to hear the warning buzzer...I'll certainly notice the throttle cutting back!
Looks like I'll finally get it back in the water this weekend. I can hardly wait...

OK, I finally got a picture of my setup on land

Anyways, maybe my anticav plate is lower than I thought? I may raise it one hole this weekend.