I finally did my first water test of the M15 I'm restoring, but I noticed that it has a centerboard clunk- I can hear the centerboard rocking back and forth left and right whenever the boat isn't heeled. I just recently replaced my old swollen centerboard with a new thinner one, and it's somewhat narrower than the width of the centerboard slot. Is this typical on an M15? Has anyone with this problem installed shims or something similar? I am planning to epoxy on some fiberglass shims to the outside of the centerboard to increase it's width slightly, but first I'd like to hear if anyone else has encountered this issue before and what they did to resolve it. I also currently have a stainless steel pivot pin, but am planning to replace it with silicon bronze at the same time as I pull the centerboard to widen it. Tyler Davis, CA M15 #157 "Defiant"
'clunking' is normal when the boat is not 'driving' (in light winds). all the boats (M15, M17, S17) do this. raise the board a few inches, putting more board in the truck, can help 'quiet the board'. -- :: Dave Scobie :: former M15 owner - www.freewebs.com/m15-named-scred :: M17 #375 SWEET PEA - www.m17-375.webs.com On Tue, Sep 16, 2014 at 11:35 AM, Tyler Backman <casioqv@usermail.com> wrote:
I finally did my first water test of the M15 I'm restoring, but I noticed that it has a centerboard clunk- I can hear the centerboard rocking back and forth left and right whenever the boat isn't heeled. I just recently replaced my old swollen centerboard with a new thinner one, and it's somewhat narrower than the width of the centerboard slot.
Is this typical on an M15? Has anyone with this problem installed shims or something similar?
I am planning to epoxy on some fiberglass shims to the outside of the centerboard to increase it's width slightly, but first I'd like to hear if anyone else has encountered this issue before and what they did to resolve it.
I also currently have a stainless steel pivot pin, but am planning to replace it with silicon bronze at the same time as I pull the centerboard to widen it.
Tyler Davis, CA M15 #157 "Defiant"
So it's nothing to worry about? My history is with swing keel boats where people generally fix this, but a short ~40lb centerboard clunking against a large contact surface is very different than an 800lb centerboard with a 6 foot pivot arm clunking against a tiny contact surface. I was just thinking it would be possible to use g/flex epoxy to bind some HDPE (cutting board material) strips to the centerboard, creating a tighter fit. I've had good luck binding HDPE to fiberglass if it's flame treated with a torch, and glued with g/flex (made for adhering to plastics). If done lengthwise and fitted perfectly, this could also create a sort of rigid gasket at the centerboard opening, reducing turbulence and drag. I've heard centerboard gaskets improve sailing performance. Tyler Davis, CA M15 #157 "Defiant" On Sep 16, 2014, at 11:28 AM, Dave Scobie wrote:
'clunking' is normal when the boat is not 'driving' (in light winds). all the boats (M15, M17, S17) do this. raise the board a few inches, putting more board in the truck, can help 'quiet the board'.
-- :: Dave Scobie :: former M15 owner - www.freewebs.com/m15-named-scred :: M17 #375 SWEET PEA - www.m17-375.webs.com
the 'fitting' of the pin is just 'compression type'; meaning the pin is held in place by how tight it fits through the shoal keel. the pin is also, somewhat, held in place with the bedding compound you used to cover the ends of the pin once it was installed. you always want to inspect the pivot pin, to assure it has not 'walked' out of the keel's pivot hole, when you trailer the boat and after removing it from the water. Jerry's tolerance for the board-to-trunk-wall was small. if your new board is narrow the 'gap' will be larger so more 'room' for clunking. if a shim makes you 'sleep better at night' go for it ... i'm assuming you know you just want a shim at the 'top' of the board ('top' in this case means the portion of the board that remains in the truck when the board is extended). you don't want shims to mess with the foil shape as this will ruin the boat's windward ability and slow it down on all points of sail. see picture attached that outlines the portions of the extended centerboard that are 'inside' and 'outside' the trunk. -- :: Dave Scobie :: former M15 owner - www.freewebs.com/m15-named-scred :: M17 #375 SWEET PEA - www.m17-375.webs.com On Tue, Sep 16, 2014 at 12:41 PM, Tyler Backman <casioqv@usermail.com> wrote:
So it's nothing to worry about? My history is with swing keel boats where people generally fix this, but a short ~40lb centerboard clunking against a large contact surface is very different than an 800lb centerboard with a 6 foot pivot arm clunking against a tiny contact surface.
I was just thinking it would be possible to use g/flex epoxy to bind some HDPE (cutting board material) strips to the centerboard, creating a tighter fit. I've had good luck binding HDPE to fiberglass if it's flame treated with a torch, and glued with g/flex (made for adhering to plastics). If done lengthwise and fitted perfectly, this could also create a sort of rigid gasket at the centerboard opening, reducing turbulence and drag. I've heard centerboard gaskets improve sailing performance.
Tyler Davis, CA M15 #157 "Defiant"
On Sep 16, 2014, at 11:28 AM, Dave Scobie wrote:
'clunking' is normal when the boat is not 'driving' (in light winds). all the boats (M15, M17, S17) do this. raise the board a few inches, putting more board in the truck, can help 'quiet the board'.
-- :: Dave Scobie :: former M15 owner - www.freewebs.com/m15-named-scred :: M17 #375 SWEET PEA - www.m17-375.webs.com
Thanks Dave! I'll need to test it on the water, but I think you solved the problem with the diagram- I think I was sailing with the board too low, to the point where very little board remained in the trunk. I had the lowest point of the top of the centerboard between the pin and pendant just flush with the keel, but it sounds like it should be a few inches higher than that. Tyler Davis, CA M15 #157 "Defiant" On Sep 16, 2014, at 11:54 AM, Dave Scobie wrote:
the 'fitting' of the pin is just 'compression type'; meaning the pin is held in place by how tight it fits through the shoal keel. the pin is also, somewhat, held in place with the bedding compound you used to cover the ends of the pin once it was installed. you always want to inspect the pivot pin, to assure it has not 'walked' out of the keel's pivot hole, when you trailer the boat and after removing it from the water.
Jerry's tolerance for the board-to-trunk-wall was small. if your new board is narrow the 'gap' will be larger so more 'room' for clunking.
if a shim makes you 'sleep better at night' go for it ... i'm assuming you know you just want a shim at the 'top' of the board ('top' in this case means the portion of the board that remains in the truck when the board is extended). you don't want shims to mess with the foil shape as this will ruin the boat's windward ability and slow it down on all points of sail.
see picture attached that outlines the portions of the extended centerboard that are 'inside' and 'outside' the trunk.
-- :: Dave Scobie :: former M15 owner - www.freewebs.com/m15-named-scred :: M17 #375 SWEET PEA - www.m17-375.webs.com
On Sep 16, 2014, at 3:05 PM, Tyler Backman wrote:
Thanks Dave!
I'll need to test it on the water, but I think you solved the problem with the diagram- I think I was sailing with the board too low, to the point where very little board remained in the trunk. I had the lowest point of the top of the centerboard between the pin and pendant just flush with the keel, but it sounds like it should be a few inches higher than that.
Tyler Davis, CA M15 #157 "Defiant"
Man, I wish I had your problem! I got the opposite..... board too tight. It's a much harder fix. Ches M15 "Mouse" #153
How about this skippers Glue a fiberglass shim to each side of the trunk. Use wood shim to hold it until the glue dries. Capt. Jim Sadler Skipper sailing vessel Pelican M-15 -----Original Message----- From: montgomery_boats [mailto:montgomery_boats-bounces@mailman.xmission.com] On Behalf Of Chesley Sugg Sent: Tuesday, September 16, 2014 12:19 PM To: For and about Montgomery Sailboats Subject: Re: M_Boats: M15 Centerboard Clunk On Sep 16, 2014, at 3:05 PM, Tyler Backman wrote:
Thanks Dave!
I'll need to test it on the water, but I think you solved the problem with the diagram- I think I was sailing with the board too low, to the point where very little board remained in the trunk. I had the lowest point of the top of the centerboard between the pin and pendant just flush with the keel, but it sounds like it should be a few inches higher than that.
Tyler Davis, CA M15 #157 "Defiant"
Man, I wish I had your problem! I got the opposite..... board too tight. It's a much harder fix. Ches M15 "Mouse" #153
i'm of the opinion that 'shims' are not needed. first concern for me is any centerboard trunk inconsistency means the board will jam. also, anything falling into the cockpit pennant hole may cause the board to become more easily jammed. there are over 1000 boats out there with this centerboard design (M15 + M17 + M23 + Sage 17) and very few reports of the board falling out. i agree that reducing the gap between board and trunk, when board down, means the boat will sail a bit better. -- :: Dave Scobie :: former M15 owner - www.freewebs.com/m15-named-scred :: M17 #375 SWEET PEA - www.m17-375.webs.com On Tue, Sep 16, 2014 at 5:31 PM, Jim Sadler <jimsadler@jascopacific.com> wrote:
How about this skippers
Glue a fiberglass shim to each side of the trunk. Use wood shim to hold it until the glue dries.
Capt. Jim Sadler Skipper sailing vessel Pelican M-15
-----Original Message----- From: montgomery_boats [mailto:montgomery_boats-bounces@mailman.xmission.com] On Behalf Of Chesley Sugg Sent: Tuesday, September 16, 2014 12:19 PM
On Sep 16, 2014, at 3:05 PM, Tyler Backman wrote:
Thanks Dave!
I'll need to test it on the water, but I think you solved the problem with the diagram- I think I was sailing with the board too low, to the point where very little board remained in the trunk. I had the lowest point of the top of the centerboard between the pin and pendant just flush with the keel, but it sounds like it should be a few inches higher than that.
Tyler Davis, CA M15 #157 "Defiant"
participants (4)
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Chesley Sugg -
Dave Scobie -
Jim Sadler -
Tyler Backman