Stern Extension

[JoeWalling]

Hi Geoffrey. Thanks for your kind comments. First of, as I've said somewhere else, all we did was to continue aft all of Tony's original lines, including the 'roof'. We continued aft (about a metre) until the bottom of the hull rose up to break the waterline about 4 inches in from the end. The new transom was cut in at the same angle and with the same radius as the old one, but there is of course less of it so it doesn't look so stubby. It also means that you can 'pretty up' the existing rudder case and bolt it back on using the same fittings. This makes the whole thing quite easy to do and the resultant elegant shape - I particularly like the gentle fall of the roof - is a tribute to those original lines.

I lost most of July and August sailing time for a variety of reasons. I was most disappointed when resuming sailing to find that the boat had grown a significant beard on the waterline and no doubt all over the hulls. I'll have to rethink my antifouling during the winter. However, the boat still points as high as it did after the stern extension, as far as I can tell. Certainly it is very much better than pre - mod. Last week I took out another multihull newcomer and put him on the tiller - he could'nt believe how high she points. I've always backed the jib as a matter of habit but I think it is slower now to go through the wind and I put that down to the sludge on the hulls. However I think I can now discount the gleaming hulls as much of a contribution to the new pointing ability.

So what has caused it? No idea. But you make a point that I had not previously considered. the distance between the centreboard and the rudder has increased - by a metre and perhaps a tad more. This is quite a lot in absolute terms and a masive amount as a proportion to the original distance. I wonder if that could be it?

I still don't feel there is much more top end speed but I'm unlikley to have a better view on this whilst the hulls are scummy.

And yes the rocking - or now absence of it - is in respect of the fore and aft pitching, or hobby horsing, or porpoising as it is variously called.

I hope now to get more sailing in over the next two months so I'll report anything new. Cheers. Joe

[petrel]

Joe,

It appears that the hull extension is improving your boat in many ways. And after the "beard on the hulls" is removed I expect that it will also cause a slight increase in top speed and a higher average speed - the latter in my opinion is the most useful.

I am curious to know the results after hull cleaning.

Have a great fall sailing season.
Geoffrey

[JoeWalling]

Hi Harry

I won't be in touch with my yard for a week or so as I am out of the area. I can find out from them what the matting density is and I'll let you know.

To start with, I had not planned to use the extension space for anything other than buoyancy, so the existing transon was ground off, particularly about 4 inches from the extremities, to form a key for the extension - see picture 0853 on page 2 of this post. Matting equal to the thickness of the original hull was used to form the extension, including covering the whole of the old transom.

It was only after we had made it, that I felt the new space was too good to do nothing with so we cut through it - see picture 0878, also on page 2. I have now made a shelf in the new bit and that is where I keep the gas tanks for the outboard.

To seal the join from the outside, both the new bit and the old hull was ground away, about 4 inches either side of the join and to a depth of about half of the original thickness. This was then built back up again with matting to span the join and then finished and faired with gel coat. It is impossible now to detect where the join is.

Hope this helps

0853 0878

[JoeWalling]

Rear floats too low on earlier Telstars?

I have not seen the earliest threads on this topic and I understand they are being consolidated elsewhere on our site. I just wanted to show this picture of HUSH. The rear of her amas sit comfortably proud of the water when at rest, as does the extended rear hull. When this picture was taken, there was also 40 litres of fuel in the central hull.

Joe

[Pat Ross]

Rear floats too low on earlier Telstars?

I have not seen the earliest threads on this topic and I understand they are being consolidated elsewhere on our site. I just wanted to show this picture of HUSH. The rear of her amas sit comfortably proud of the water when at rest, as does the extended rear hull. When this picture was taken, there was also 40 litres of fuel in the central hull.

Joe

Hi Joe,

The floats look good to me on Hush, I'd be interested in seeing what others opinions are.

We could just start a new thread for 26 and 8M floats in this section. Perhaps Ron can set that up when he moves the other messages.

Pat

[Pat Ross]

The new extension is immensely strong due to the number of layers of matting and is further strengthened by the three glassed in foam cheeks that you can see. Joe

Joe,

I am a couple months from starting on my stern extension but am in the drawing and planning stages. I am looking closely at the photo where you describe the "Foam Cheeks". Is this actual foam, if so what kind, where did they get it? I attached the photo you used.

Thanks,

Pat




3 glassed foam supports cheeks.JPG (161.54 KiB) Viewed 29 times

[JoeWalling]

Hi Pat

Sorry for late reply - have been away skiing and only made contact yesterday with the guy who did it. It is stiff foam - the kind you can shape with a hot knife and it still stays semi-rigid, though it would break up if put under pressure. So it is not structural, it is just used to hold a shape whilst grp mat and resin are applied. Very light in weight, with a kind of honeycomb appearance. We don't know what its actually called though - it came from a local glassfibre company who used to use it in the manufacture of replica cars and car body parts, so you might be able to track it down from somewhere similar over there. Hope this helps,

Cheer. Joe

[Pat Ross]

Hope this helps,

Yeah Joe this does, thanks I am familiar with the product you mean.

Cheers,

Pat