Angled transomes?

There was a time when transom angles where a designer's whim. The engine manufactures, bitched and complained and a standard was set around 12 degrees. This has helped both the designer and manufacture. As for following waves or sea, I'd say any barn door will work, though some much better than others. The height of the cutouts were standardized as well, with fixed shaft lengths. We have lots of standardized stuff in the industry, folks, this isn't anything new.

Sailboats started using the reverse slope transom as a result of a radical effort to drop some weight on an AC boat in the late 50 or early 60's that was not fairing as well as the designer (Ted Brewer I think) hoped. The boat was hacked with a chain saw and had the "revised" transom on for the next round in the races. The waterline length would be about the same with both traditional and reverse transoms, but the reverse doesn't carry the weight above as the traditional does. We all know how keeping the ends light will help performance in all air propelled craft.

 

PAR, so in your scenario angled transoms came first. They were developed for what reason? Possibly wave control? Possibly aesthetics? Then with the invention and increased popularity of the Outboard manufactures forced their hand a bit and demanded a standard angle? So in the chicken and the egg question that opened it up the answer is the angled transom came first.

 

Woodboat said, "So in the chicken and the egg question that opened it up the answer is the angled transom came first."

A book on old outboards shows that most of the earliest outboards were built for a vertical transom. Later ones went to the angled transom. This bit of anecdotal evidence would indicate that the outboard makers wanted the change to an angled transom and later to a standard angle of 12 degrees as PAR said. Makes sense to me.

 

First off I do NOT know the answer or else I would be arguing tooth and nail to convince everyone. PAR stated
"There was a time when transom angles where a designer's whim. The engine manufactures, bitched and complained and a standard was set around 12 degrees" He didn't say there was a time when all transoms were vertical until engine manufacturers complained. I read that as they might be 0, 12, 24 whatever. So if I am reading PAR correctly then angled transoms were around in various forms, for whatever reason. prior to outboard motor companies demanding 12 Degrees. So, on a boat equipped with inboards what is the purpose of an Angled transom?

 

See my previous post!

 

Oh, I read your post, I want one of the other guys to say it.

 

Woodboat,

If you are looking for an argument, forget it. I'm not interested.

 

Angled transoms

Because efficiency is best when prop shaft is parallel to water surface, the boat design should not need much trim adjustment unless the trim angle of the boat varies dramatically with speed or loading changes.

nevd

 

Angled transoms

Being a new guy, I didn't use the system correcly and posted the reply to these questions later in the thread.

nevd

 

nevd - nothing wrong with being a new guy
I understand that when the o/b is trimmed normally, there won't be a problem. I was thinking more along the lines of what might occur if the driver thought to herself ( ) "I wonder what would happen if I pushed this button...." and trimmed the motor right in whilst travelling at speed.....

 

Yes, plumb transoms were the norm, but style and function usually dictate design changes from a pervious model or new work.

The rake of the transom on powerboats has been standardized because transom angles couldn't be held within the degree of bracket design that the manufactures could live with. Each engine built needing several different brackets to cover a wide range of transom angles that could and have been designed, isn't very cost effective. Hence the standardizing, brought about by the many different transom configurations on each different design.

There have been plumb, raked and curved transoms, over the years. I don't know which one came first, but what would the point of standardizing be, if they were reasonable close to the adjustability found in most bracket designs.

I do know that there was a great deal of debate between designers and engine manufactures as to what was going to work best. The plumb transom was replaced with a slightly raked one as soon as designers started building around the latest offering from their favorite outboard builder (or the one whom hired them). The angle moved around a bit until this about 12 degree thing was settled on. Transom heights and well shapes all went through a feeling out period before designers and engine manufactures got there acts coordinated.

To answer the other question of why rake to an inboard installation. Women, did it. Women and marketing folks. The same people responsible for cloth cover headliners (so that you can't find the leak unless you rip down a bunch of costly fabric), plaid cushion covers (to match the curtains) and ice boxes that can't be loaded from the dock. Fad, trend, whim, the uncontrollable desire to just change things that designers have innate about them. A nicely raked transom looks cool man, and we all want to buy something to been seen looking cool in. Style shouldn't be confused with design criteria, as a 12 degree transom in either direction will not help very much in a following sea or slap down a boarding wave. For that you need St. Christopher.

 

Will, the boat response is the same as having unacceptable load in the bow section and the speed drop and heavier steering as additional in trim is applied produces a natural reluctance to trim in even more - most outboards also allow an adjustable limit to in trim.

nevd

 

I was not looking to argue for argue sake. The original answer didn't seem that plausible to me. The women answer although very funny doesn't seem quite right either. I am not a designer, I simply have a passion for all things water related. The same as the other user here that is an offshore fisherman it is my experience that an angle does help keep swells from coming over as well as when backing down. They could have made the transom any angle, the cost to mount would have been the same. I believe that 12 degrees filled the most checks on a spread sheet of pluses and minuses.

 

You'll find most everything currently in boats not related directly to improved speed is to please women. We have two income households now, the woman in our lives require a more advanced role in the selection and setup of a yacht.

Galleys were moved aft to get them into the conversation with the watch and to keep "cookie" in the most comfortable part of the boat, otherwise she may not want to go. When they're happy, all's well. Interior design in yachts today is geared to get her to let you buy it. Guys could care less if the carpet doesn't match the countertops, give us a bottle opener on the side of a cabinet and we're generally happy. We lived for hundreds of years without most of the contrivances seen on boats today. In the last 40 years, a lot of good design elements have taken a back seat to the marketing folks vying for the women power and influence over their other halves.

A piece of sheet aluminum screwed to the upper lip of a plumb transom with an inch or so exposed past the aft edge would keep as much sea out of the 12 degree raked well would. Yes the angle does help some, but not a lot.

Yes, the transom rake could have been any angle, manufacture's would have designed around the standard, but near 12 degrees was what was thought best for the engine to have some "in" trim room. You don't need much of this trim before you are plowing.

 

I agree in part. I know pleasing women has a huge role in design and colors today. Heck, like you said look at any new boat with bubble shaped decks and carpet on the ceiling. We had angled transoms as long as I have been boating. Granted that's only 40 years but I just don't think women had a hand on that one. Again I could be wrong. It just seems like women started to matter in the 80's while transoms were angled well before that. I just bought another boat today, It's a 1976 model so it lacks a lot of girlie stuff