Re: transom and deck

DELFTship forum Hull modeling transom and deck Re: transom and deck

John R. Coil


I’d be willing to answer any of your questions that I can answer; however, I’d rather do so on the forum.

Partly because, if I can answer it, it may help others with similar questions.

But also, and this is important, if I can’t answer a question someone else might and we’d both be helped.

Now, having said that: after I posted that how-to I remembered a few addendum that can’t hurt sharing.

First off, the formula for finding the offsets for a curved surface the way I showed you is also useful for obtaining the offset values for curved deck with a constant radius — even when the sheer line is something saddle-like as Rhodes and other classic designers used. Remember to use large radii to do this. The trick here is to start by assuming the sheer line, and your radius, and then working back towards the center of the ship.

But as far as transoms go you can obtain somewhat different results by independently moving the upper line of your transom layer to its location on the sheer line and then moving the lower line to its position on the keel like. Compared to rotating the surface and then moving it the result here will have less of an upswept feel to the transom.

Also, if you want your transom to both start and end at a particular point and like the upswept feel that rotating comes with this can be easily achieved by first choosing an angle to rotate the transom through that seems like it would be close enough and then hand selecting the edge less precisely placed and moving it however far you need to nudge it to get it on target.

Time permitting I’ll pull up a model and produce a number of different transoms to show what effects, that I know how to achieve, may come out.

There are, of course, certainly other tricks to be used: that I can’t describe (having not used them even if I may think they’ll work) or even know about … for example, I’ve suspected — though never attempted — that this may help in producing a rounded stern. As for what I don’t know: “I don’t know what I don’t know.” — James T. Kirk … to which I’d add: “I suspect it’s rather a lot though….” 😉