1966 Starcraft Holiday Engine Repower

[jbcurt00]

You need 2 - 2.25in thru the keyhole for a Mercruiser driveline, so there is a 3rd layer of plywood (on an aluminum boat, usually a layer of 1/2in) around the thru hole, on top of the assembled 1.5in transom plywood.

Not 100% familar w the I/O Holiday, so I'm not sure what 12in panel has to come off.....

Yep, pull the transom/rubrail corner caps, bend/cut the gunwales......

Pix are helpful, but shrink wrapped for winter hampers that....

 

[Watermann]

Your 18' IO Holly is the same as my Chief. Yes the end caps come off to remove the transom cover and a portion of the rubrail to drill out the blind rivets that go through the transom cover and gunnels. Then you can just cut the end of the gunnel where it goes under the end caps. Although I recommend taking off the gunnels and replacing the blind rivets with new.

The horse collar is a 1/2" piece of plywood that goes on the inside around the keyhole, you'\ll see when you pull the motor.

You'll want to build a new front motor mount as well while your at it.

 

[66Holiday924]

Thanks! I'm glad I brought this project to this site. I've got probably 100 hours of reading through forums and searching Google and I haven't seen anything about a horse collar. If I have enough wood from one of my 3/4" panels can I use it for the horse collar, or do I need to buy a sheet of 1/2" marine grade plywood also?

​After I install the new transom the boat is going to a mechanic to have a newer engine installed. I'm sure they would replace the motor mount too. They probably have to for the new engine.I was planning on talking to them about it though. They are going to cut the new keyhole too. I'm upgrading to an Alpha 1 Gen II.

 

[jbcurt00]

You NEED a piece of 1/2in.

3/4ply sealed
Glued to a 2nd piece of 3/4ply sealed
Aluminum transom skin

Plus 1/2in sealed ply gives you @ 2.125in (2 1/8th)

Which is exactly centered in the targeted 2-2.25in thru the keyhole

Sealed 3/4 is too much

 

[66Holiday924]

Sounds good. I think I have about as much understanding of building the transom and installing as I can possibly have without taking the shrink wrap off and looking at it. I will be removing that panel across the back and that is going to involve removing screw, rivets, loosening the rubrail, and possibly cutting the gunnels.

​Can we talk about hardware? I'm thinking that using through bolts with washers and nuts is going to be a better option than screws (which I believe is how it is fastened on currently). Are through bolts the way to go?

​On a side note, I named the boat Edward J. Cross. I figured a Vietnam era boat ought to be named after a fallen Vietnam hero. My idea was to pick a name at random off an official memorial website. I specifically wanted a low-key soldier or sailor who doesn't already get a lot of recognition. So, if you haven't named your old boat, or you're struggling to come up with a good name, I think this idea is a winner for these old Vietnam era boats.

​I think my boat looks like an Edward too...

 

[66Holiday924]

Should I use through bolts on my transom?

 

[Bondo]

Ayuh,.... Some will be thru-bolts, some will be screws, 'n some will be rivets,....

 

[Watermann]

I'm thinking once you get into the tear down things will become very apparent without the fog of memory. Just so it doesn't get foggy again when it's time to replace it all, be sure you take loots of pics.

 

[66Holiday924]

Use high quality Stainless Steel coated with tef-gel? I'm thinking nylon washers on the outboard side where they will be in contact with the aluminum and Stainless washers where they will be in contact with the wood.

 

[66Holiday924]

I've been looking more into something that was said regarding the horse collar earlier in this thread. I am going to be installing an Alpha 1 Gen II after the transom is rebuilt. As I understand it, the transom is 1.5 in. thick but will need to be 2-2.25 inches thick at the keyhole. This is why you add the horse collar. My questions are:

​Are we talking nominal thicknesses?
​Does that thickness at the keyhole include the Aluminum skin?

​I was told that if I use two 3/4'' sheets of plywood and one 1/2" I'll end up with 2-1/8 at the keyhole. It doesn't add up, especially with the nominal thickness of plywood. Does the sealing of the wood add thickness that is also counted in this? Is marine grade plywood a true 3/4"? Given nominal sizes, (23/32 for 3/4" plywood and 19/32 for 5/8"), if I am shooting for 2 to 2-1/4", two "3/4" sheets and a "5/8" would put me at 2-1/32" but if I used the 1/2" (which has a nominal thickness of 15/32), I would be short. it comes out to 1-29/32".

 

[Bondo]

​Are we talking nominal thicknesses?
​Does that thickness at the keyhole include the Aluminum skin?

Ayuh,... It's all 'bout the total thickness of the assembled transom,....
This determines the length of spline engagement of the coupler, 'n input shaft of the drive,....

Shoot for as close as possible to 2",.... but not less,....

 

[66Holiday924]

Thanks bondo. Do any of you guys have any experience with stern saver boards? I'm thinking about adding those when I get everything put back together.

 

[Watermann]

I made my own version of a transom board out of AL on my SS so I could easily replace the backer piece if I change transducers or get too many holes in it. In the pic all that's on it is the speedo pitot but I have a transducer on it now.

 

[66Holiday924]

I've been going through your restore threads Watermann. You do really good work. I would call them rebuilds. You strip them down to nothing, even the paint. How is the tractor paint holding up on the Chief? I'm thinking I will have to repaint my transom when I'm done with this project. I think my Holiday is very similar to your chief, as far as the hull goes.

 

[Watermann]

Thanks for taking a look at my thread and yes our 2 hulls are most likely identical. I don't know the exact year they redesigned then but the early 60's model Holly's had a rounded bottom rather than the V deadrise type like my Chief has as you can see in the pic below.

The Van Sickle tractor paint with catalyst hardener has been very durable so far and I have no complaints. I've had guys looking at the paint and ask if it was powder coated due to the look the paint and finish has.

 

[66Holiday924]

I am considering painting my transom. I'm reading that one of the drawbacks to linseed is that it is prone to having mildew grow on it. So I am considering painting it with either the primer you suggested earlier in this thread or the tractor paint. Do you think the tractor paint will suffice? I was also going to do the gluvit on the seems and paint the inside of the stern sheet with some POR-15 that I have leftover from another project. The POR-15 is awesome stuff, it's hard and flexible at the same time and it is an anti corrosion paint. I am thoroughly impressed with it. What do you think about painting the inside of the stern sheet?

​I realize that a lot of these questions are probably answered in your thread but I haven't been able to go through it page by page yet.

 

[Watermann]

After cleaning the inner transom AL, I filled the pitting with Marine Tex, sanded, SE primed and put 2 coats of paint on it for protection.

The transom wood needs to be sealed, the best way to do it is a matter of opinion for the most part. Paint is a great way to seal it as long as it's oil based and not latex. The industrial tractor paint is inexpensive and very durable. All of the through holes and screws should have 5200 in them to seal and the wood from water penetration.

On the IO configs, the keyhole is of special concern. I filled any voids in the plywood with JB water weld, sanded and then sealed over with Spar and paint. I do the same with the top edge of the transom wood as well so there's no place for water to collect and sit.

 

[66Holiday924]

I'm thinking that I am going to seal the transom wood with the old timer formula that you recommended but then I'm thinking about painting it too because I read that there is a reputation for mildew growing on wood that was treated with Linseed Oil. I'm thinking the tractor paint might be good for that.

I'm not going to be installing the new engine. I don't have the setup to even consider it. My boat is going to a shop in Wisconsin to have that done. When Mercruiser couldn't answer questions about the engine swap they recommended that I speak with this shop a couple of miles from their factory. I talked to them and they know they are going to get my boat with a no keyhole in it at all. They are going to handle cutting that out. I'm going to try to get them to treat the keyhole once it is cut out.

​People seem to have different opinions about where to use 5200, 4200, and 4000. I'm still reading about that. I was thinking about 5200 where I use rivets that are not supposed to be removed ever again and 4200 around hardware and through bolts that will be removed every couple of decades or so. Everybody says the 5200 works for everything. The only drawback I'm hearing is you're in for a hell of a time if you ever have to remove it. They're saying 4200 seals the same it's just easier to work with later.

 

[BWR1953]

I'm thinking that I am going to seal the transom wood with the old timer formula that you recommended but then I'm thinking about painting it too because I read that there is a reputation for mildew growing on wood that was treated with Linseed Oil. I'm thinking the tractor paint might be good for that...

I used the Old Timers Formula on my Kingfisher transom and I'm planning to also paint it for aesthetics upon final installation.

 

[Watermann]

I've gone through a few construction tubes in my rebuilds and I can tell you 5200 is a powerful adhesive between flat surfaces but when it comes to a bolt or screw with limited surface area it can't stand up to the torque and removes just as easily as any other sealant.

If you look at the transom pic above of my SS, you'll see that motor pad under the trim unit, that won't ever come off again without destroying it as the entire thing was back buttered with 5200.