{"id":596,"date":"2010-03-29T16:49:50","date_gmt":"2010-03-29T06:49:50","guid":{"rendered":"https:\/\/currentsunshine.com\/?p=596"},"modified":"2010-03-30T12:58:56","modified_gmt":"2010-03-30T02:58:56","slug":"speed-test-not","status":"publish","type":"post","link":"https:\/\/currentsunshine.com\/?p=596","title":{"rendered":"Speed test &#8211; not."},"content":{"rendered":"<p>A glassy smooth Careel Bay beckoned me to do some speed trials.\u00a0 Cos so far there&#8217;s always been a bit of wind and it wasn&#8217;t clear just how much the wind was contributing to, or slowing her speed.<\/p>\n<p>So I dropped the mooring and started taking notes as she wove out through the moorings.<\/p>\n<p>1630 watts = 4.5 knots<\/p>\n<p>4600 watts = 6.2 knots &#8211; full throttle<\/p>\n<p>Strange&#8230;\u00a0 in earlier tests I was confident that she was topping out at about 6.5 knots so this is odd to see maximum speed a little less than I expected.\u00a0 Perhaps those readings were wind assisted.\u00a0 Anyway, back to it. I&#8217;m using the stop watch on my<em> iPod Touch<\/em> to time how long it takes to  come to a full stop.\u00a0 And then I can do the same test late with the  standard prop. Back to neutral and then to full power in reverse.<\/p>\n<p><strong> <\/strong><\/p>\n<p><strong> <\/strong><strong>Clunk<\/strong><\/p>\n<p>and the watts drop off to around 700.\u00a0 What was that? Can&#8217;t see any obstruction to the prop. Try forward &#8211; also in forward the maximum load is about 700 watts.<\/p>\n<figure id=\"attachment_604\" aria-describedby=\"caption-attachment-604\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-604\" title=\"sheared pin1\" src=\"https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin1-300x225.jpg\" alt=\"\" width=\"300\" height=\"225\" srcset=\"https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin1-300x225.jpg 300w, https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin1-1024x768.jpg 1024w, https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin1.jpg 1280w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-604\" class=\"wp-caption-text\">Broken ends of pin sat at a nice angle to grab the shaft<\/figcaption><\/figure>\n<p>I suspect the shear pin may have broken. Now I&#8217;m worried the prop might fall off, so I throttle back to about 100 watts and she&#8217;s going along at 1.5 knots.\u00a0 I haven&#8217;t gone far from the mooring, the day is still calm, so I&#8217;ll limp back ok at this speed.<\/p>\n<p>Sure enough the ends of the pin have sheared off as designed and have laid against the shaft in such a way that they still grab a prop a little.\u00a0 700 watts worth actually.<\/p>\n<p>Speculating about the maximum speed being reduced, and remembering having hit some big jellyfish last weekend, its likely that the prop has been slipping just that little ever since the jelly fish encounter. One of them really got hit with the prop and the motor almost stalled, and it was probably then that the pin sheared.<\/p>\n<figure id=\"attachment_602\" aria-describedby=\"caption-attachment-602\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin2.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-602\" title=\"sheared pin2\" src=\"https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin2-300x225.jpg\" alt=\"\" width=\"300\" height=\"225\" srcset=\"https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin2-300x225.jpg 300w, https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin2-1024x768.jpg 1024w, https:\/\/currentsunshine.com\/wp-content\/uploads\/2010\/03\/sheared-pin2.jpg 1280w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-602\" class=\"wp-caption-text\">Pin ends have rubbed a slight groove in the shaft<\/figcaption><\/figure>\n<p>So its rather clever of me to have decided to do this test today in perfect calm, and discover the problem.\u00a0 Otherwise I may not have noticed until the chips were down and I really needed it. I now think the clunk I heard was the pin ends swapping around as the load reversed on the prop.<\/p>\n<p>Its nice that the nut didn&#8217;t come undone with the free spinning of the prop on the shaft. And drop the prop into the sea.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>A glassy smooth Careel Bay beckoned me to do some speed trials.\u00a0 Cos so far there&#8217;s always been a bit of wind and it wasn&#8217;t clear just how much the wind was contributing to, or slowing her speed. So I dropped the mooring and started taking notes as she wove out through the moorings. 1630 &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/currentsunshine.com\/?p=596\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Speed test &#8211; not.&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","footnotes":""},"categories":[2],"tags":[],"class_list":["post-596","post","type-post","status-publish","format-standard","hentry","category-electric-propulsion"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/currentsunshine.com\/index.php?rest_route=\/wp\/v2\/posts\/596","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/currentsunshine.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/currentsunshine.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/currentsunshine.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/currentsunshine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=596"}],"version-history":[{"count":7,"href":"https:\/\/currentsunshine.com\/index.php?rest_route=\/wp\/v2\/posts\/596\/revisions"}],"predecessor-version":[{"id":603,"href":"https:\/\/currentsunshine.com\/index.php?rest_route=\/wp\/v2\/posts\/596\/revisions\/603"}],"wp:attachment":[{"href":"https:\/\/currentsunshine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=596"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/currentsunshine.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=596"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/currentsunshine.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=596"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}