Boston Lock Pusher Tug

[Chris EParticipant @chrise]

Does anyone else think that the Boston Lock pusher tug in the Winter Special reminds them of the Motorflote design of around 30 years ago? The Motorflote had diectional stability and reversing issues just like Boston Lock and builders made subtle changes to minimize the problems. The Boston Lock article talks about the photos showing how this was corrected but they don't that I can see.

The Motorflote design was 10in x 8in so I suspect that the dimensions of Boston Lock are a little more conventional.

As the subscriber who let me see the Special had not got the plan with them will someone please tell me the dimensions of Boston Lock as designed?

 

 

Edited By Chris E 1 on 24/10/2019 09:04:46

[Chris EParticipant @chrise]

[Chris EParticipant @chrise]

54 views & not a single reply. Oh well.

[Colin BishopModerator @colinbishop34627]

Chris,

The published plan is 12 inches long and 5 inches wide.

The shaped underwater section is 9.75 inches long and 2.77 inches wide. Whilst the upper hull is generally rectangular witha slight bow taper, the lower section is tapered at both ends.

Colin

Edited By Colin Bishop on 25/10/2019 12:18:45

[Chris EParticipant @chrise]

Thank you Colin.

The tapered at both ends lower section is what seemed to help with the Motorflote as well.

[Colin BishopModerator @colinbishop34627]

Having now had a look at the article it is pretty obvious what was wrong initially. When going astern the prop was simply pushing water against the flat face of th rear of the lower hull so there was no astern thrust, the water was simply being flung out to the sides.

By tapering the lower hull the wash from the prop would actually pass along the side of the hull and give some sternway although I suspect it will be more to one side than the other as the taper on the modified hull is actually quite blunt. If building the model myself I would be inclined to make it a bit more pointy.

Colin

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