A 33ft Sumner ?

[SAE140]

I don't know if anyone else here has a design in their heads which never goes away - every few years or so you factor in a new idea, but it still isn't quite right - so the design gets shelved away again for a couple more years ...

This has been the case with me ever since I first saw the lines of Blondie Hasler's experimental boat 'Sumner'. I can't say why this should be - it's one hell of an ugly duckling, and at 46 feet LOA (32.5ft LWL) and a beam of just 6.75ft, exactly what would I use the boat for ??

My current 'ideal concept boat' should be capable of travelling through the British and French canal systems, yet still be capable of a fair sailing performance offshore. In a perfect world it would also be road-trailerable, capable of being towed by an average car.
The only options I'm aware of to fit this brief would be one of the myriad number of 21ft(ish) UK twin keelers (of which I have a Kingfisher and a couple of Corribees) - but life aboard these craft is cramped to say the least. The Manitee 'Alert', and Bolger's sailing narrowboat design (the name of which escapes me) would be better craft for living aboard, but neither of these would be road-trailerable - and they're probably not great sailers.

The Sumner design, as is, falls over both on it's length, it's 4ft draft, and it's displacement - which I'm guestimating (from Hul's figures) as being in the order of 4 tons.

This year's Southampton Boat Show saw a brilliant keel design by http://www.mitchellyachts.co.uk and I'm attaching a couple of pics of their invention. Immediately I saw this invention my mind vectored back to Sumner's twin ballasted keels.

Now - if the Sumner design is scaled down to 33ft LOA, the displacement is reduced to something around 1.5 tons - which then becomes very trailerable - and with parallelogram torpedo keels *pulled up flush with the hull*, a draft of only 5 or 6 inches results. Very beachable - with a kick-up/lifting rudder of course.

I'm still in the process of fine-tuning the Huls offsets to get a perfect match with the published lines (the only info I have), but I'll post the figures (prismatics etc) if anyone's interested.

A reduction of the beam to only 5ft doesn't appeal much, but then again - life ain't perfect.

As with a previous post, if anyone sees any glaring 'whoopsees' or wants to comment re: the feasibility and/or the likely sailing performance - comments would be most appreciated.

'best

Colin

[Tad]

Colin,

Cool idea, but some windows might be really nice!

The drag from that stub keel will be horrendous, what's it for??? (That's a rhetorical question implying you might want to rethink your keel.)

A vertical retracting board with ballast bulb is simple and strong...



Tad

[SAE140]

Hi Tad

ahh - windows/lights ... I know these are conventional fittings, and we expect to see 'em on boats - but why have 'em ? They have a tendency to leak, they're useless to look out from, and large ones are vulnerable from airborn green water. Personally, I favour raised hatches (Griffith's hatches) using thick perspex and placed on the centreline to get the light in. But I do agree that windows *look* the part.

I fully agree with you about the stub keel - my preference would be to pull the ballast torpedo up into a recess in the hull, giving absolute minimum draft for beaching. Fit shallow chine runners if directional stability is still needed.

Ballasted dagger-board ? Well, I've no problem with dagger-boards, providing they incorporate a weak spot so that they will break off during a hard grounding, and thus preserve the integrity of the hull. So for me a ballasted dagger-board would never be an option - thinks - unless the board could be arranged on the *outside* of the hull, leeboard-style, to pivot-breakaway backwards and slightly outwards during a hard grounding. That might be possible. Certainly an option worth considering, although there'd be a need to prevent the board from breaking away under normal heeling stresses - which could prove embarrassing.

I guess I'm just smitten by the idea of putting a very heavy lump of ballast (I'd use a s/s tube filled with lead to eliminate electrolysis) on the end of 2 s/s struts - putting the weight in exactly the right place, and using fiendishly strong stuff to fabricate with. 6" draft or a 4-5ft draft - I reckon the idea could be a winner.

Much appreciate your post.

Colin