Blazer Sport 40

[Kerry Norton]

I could really use some help with a little problem with my Whiplash. For the most part this is a great boat, good speed, turns great but sometimes while running with the wind (choppy water), the transom will kick up and cause the boat to dive. I'm running a slightly wider strut (to accomodate the thrust bearing for square drive), with the corners rounded off except for abount an 1/8th of an inch down the centre, set flat 7/8th's of an inch deep with an X450/2 detounged and Barr cut. Any help on this would be greatly appriciated. Thank you Kerry

 

[Bob Blazer]

Hi Kerry - You say it subs going with the wind. Does it sub going aganist the wind? I'm not saying that this is your problem but sometims the front sponsons will actually suck the boat down. Try putting a shim on the front sponsons with the back edge sharp and prox 1/8" deep. If you have some shingles on there now make sure that the back edge is sharp. Hope this works. You could also take a little angle out of your strut.

Bob

 

[Kerry Norton]

Bob..thank you for the response, the strut is set with no angle now. When you suggest using a shim, do you mean 1/8th at the back of the sponson and tapered nothing towards the front? The problem seems to be primarily going with the wind, boat airs out nicely going into the wind. Where should the boat balance? thank you Kerry

 

[Kerry Norton]

Here's a mock-up of a possible shingle (step) idea for my Whiplash. 1/16th inch spacer at the rear with a 1/16th step. Has anyone experimented with an arrangement like this? thank you Kerry

 

[Lay26]

i've built 3 and currently the last version withouth shims and never had that isssue. i notice that your drive dog is quite under the transom which may cause any propwash to push the transom up and stuff the nose....just a thought. my drive dog is 1 drivedog length behind the transom as per namba rules

 

[dave roach]

Kerry

The best thing you can do is cut the air traps all the forward on the sponsons.

Dave Roach

 

[Bob Blazer]

Here's a mock-up of a possible shingle (step) idea for my Whiplash. 1/16th inch spacer at the rear with a 1/16th step. Has anyone experimented with an arrangement like this? thank you Kerry

Kerry - If it was mine that is what I would try. You could just CA tack them on to try. I think you will like the result. It will also mill better and get on plane quicker.

Hope this helps - let us know.

Thanks Bob

 

[FloridaScaleBoater]

I could really use some help with a little problem with my Whiplash. For the most part this is a great boat, good speed, turns great but sometimes while running with the wind (choppy water), the transom will kick up and cause the boat to dive. I'm running a slightly wider strut (to accomodate the thrust bearing for square drive), with the corners rounded off except for abount an 1/8th of an inch down the centre, set flat 7/8th's of an inch deep with an X450/2 detounged and Barr cut. Any help on this would be greatly appriciated. Thank you Kerry

Only thing I would like to add,,, is your strut hole not sealed? when you are running it.

If not, you could be taking on water while running and getting too nose heavy during the run??

Just a thought

 

[Kerry Norton]

Hey guys thanks for the input. The picture of the strut is a little misleading, the drive dog is almost entirely behind the transom short of a 1/16th of an inch. The strut is sealed. Here's another picture of a slightly different mock-up for the shingles. For the record, this is my second Whip, the first is excellent with no bad habits, so I've done something, somewhere on this one. thank you Kerry

 

[Terry Keeley]

For the record, this is my second Whip, the first is excellent with no bad habits, so I've done something, somewhere on this one.

RU running a different prop?

 

[Kerry Norton]

Terry...I thought I was, the first Whip is running a CMB purple head with a stock X450/2, the second Whip is running a CMB HR, the HR would bog off bouys 3 and 6 with the stock prop, I detounged and Barr cut an X450/2 for this setup. Kerry

 

[Terry Keeley]

Terry...I thought I was, the first Whip is running a CMB purple head with a stock X450/2, the second Whip is running a CMB HR, the HR would bog off bouys 3 and 6 with the stock prop, I detounged and Barr cut an X450/2 for this setup. Kerry

Ding, ding, ding! :lol:

Both of those will add quite a bit of lift to an X series prop making it act more like a 14 series.

I'd go back to the stock X450/2 and pull the pipe out a little or maybe try a stock X447/3 or even a X448. Another option would be to use the cut 450/2 and raise the strut a bit.

 

[dave roach]

Bingo Terry

Dave

 

[Kerry Norton]

I've always thought the main purpose of the Barr cut was to reduce loading of the prop in the turns...and that the notches in the trailing edge of the blades reduced the amount of water the blades threw , reducing lift. A little Advil would help here...Kerry

 

[Terry Keeley]

I've always thought the main purpose of the Barr cut was to reduce loading of the prop in the turns...and that the notches in the trailing edge of the blades reduced the amount of water the blades threw , reducing lift. A little Advil would help here...Kerry

Might do that to some extent on a constant pitch prop like a 14 or 16 series, but doing it to an X cuts away a bunch of the progression at the TE increasing lift.

 

[FloridaScaleBoater]

Terry...I thought I was, the first Whip is running a CMB purple head with a stock X450/2, the second Whip is running a CMB HR, the HR would bog off bouys 3 and 6 with the stock prop, I detounged and Barr cut an X450/2 for this setup. Kerry

Kerry,, Terry;

Something I noticed on my PT sport-40, the X447/3 had quite a bit more lift than the original prop I was running on my boat. I ran for years, with a Y547/2 with good results.

Someone,, Can't remember who, suggested I try the X447/3 I did, and actually like the prop better on my setup. My only point here, is the X447/3 creates quite a bit of lift, and would try the Y547/2 if Kerry is stuffing the nose>>

Just my .02 cents

 

[Kerry Norton]

Just to follow up...first, thanks to those who responded, finished testing with various changes. The shingles on this already excellent hull were a positive change, boat seems a little faster but accelerates quicker from low throttle...didn't resolve the stuffing issue. I've run this hull with X447/3, X450/3 and X646/3, these props glued the boat to the water, the X450/2 always kept the boat loose, an X447/2 (stock) would also kick the rear up. The boat never looked as if the rear was being lifted up but rather "hit" which caused me to look at the strut. A friend noticed that I didn't knife-edge the lead on the strut, didn't really think that was necessary with surface drive..doh...finihed maching the lead on the strut and smoothed out the lead to the stuffing tube (look at photo in earlier post), boat runs amazing with the modded X450/2...now if I could just fix the guy driving it....Kerry

 

[Bob Blazer]

I am happy that you are pleased !!!!

Thanks The Dad

 

[Charles Perdue]

Just to follow up...first, thanks to those who responded, finished testing with various changes. The shingles on this already excellent hull were a positive change, boat seems a little faster but accelerates quicker from low throttle...didn't resolve the stuffing issue. I've run this hull with X447/3, X450/3 and X646/3, these props glued the boat to the water, the X450/2 always kept the boat loose, an X447/2 (stock) would also kick the rear up. The boat never looked as if the rear was being lifted up but rather "hit" which caused me to look at the strut. A friend noticed that I didn't knife-edge the lead on the strut, didn't really think that was necessary with surface drive..doh...finihed maching the lead on the strut and smoothed out the lead to the stuffing tube (look at photo in earlier post), boat runs amazing with the modded X450/2...now if I could just fix the guy driving it....Kerry

Kerry, you may want to try increasing the number of the shingles and spacing the shingles closer together. This increases the angle of attack on the trailing edge of the shingles plus increases the number of ride surfaces to allow the boat to find its "Sweet Spot" easier. When testing I use a very thin double sided tape to mount the shingles to the sponsons. One other trick is to CA the rear of the shingle to harden it so that it can be sanded almost razor sharp after undercutting it at about a 30 degree angle. This helps the shingle to break free of the water even quicker and handle the chop better.

Charles