Blazer marine sport 40

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jameswelbaum

Well-Known Member
Joined
Jun 14, 2011
Messages
54
I’m looking for a strut, rudder and turn fin recommendation for a BM sport 40. The P/N’s in the manual that came with the kit don’t exactly line up with anything on the speed master website that I could find. I understand I’m basically looking for sport 20 rudder, strut and a sport 40 turn fin but was wondering if someone could provide exact P/N’s?
 
Mojo Sport 40 turn fin. Google Mojo racing products. He has some turn fins unless you can find a Tyndall. I have a Blazer Sport 40 fin I can sell you. It’s used.

I’ll try and find some part numbers for you that will work.
 
I’m thinking I want to mount the strut under the boat. What are the pros and cons? Also I’m interested in the blazer marine fin.
 
Some boats like it some don’t. It’s a lot easier to Mount on the transom. A lot less work. I’ll get you some pics tomorrow of what I got on the turn fin.
 
Mounted mine off the transom. I used LBA style rudder (2-1/4” offset) also mounted on the Left side of transom.

A .21 flat bottom strut.

Mojo Racing Sport 40 fin and bracket.

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I'm going with the SPDS-005-FSpt 20 Strut Assy F/B for my new PT sport 40 I'm working on. Those are the correct numbers and such Straight off the tag
of parts Speedmaster sent me. 6-2-2021. This is what Phil is referring to with his dimensions/illustrations for his new Stealth sport 40. That puts the strut out back from the transom a ways. IMPBA rules allows prop to be up to 3 inches behind the transom. Will be heavier than mounted to the bottom of the boat. But may make the boat a bit more stable in rough water??? Ken
 
Phil Tomas suggest SPDRS-007-SNGA for the rudder. That is a 20 size rudder extended out to match the extended strut.
If you are going with the strut under the hull, the standard Speedmaster 20 rudder for a rigger will work well. I don't have the current part number for that one... Ken
 
Here is mine with what I posted above, if you want to see it on the boat. I let the bracket overhang and 45’d it to match the lines. Also used what speedmaster calls “short” strut brackets.
210EC103-B082-44BE-A713-B779A456B623.jpeg
 
Can someone explain the stability gain by having the strut hang off the back of the transom? I’m not quite understanding that.
 
Can someone explain the stability gain by having the strut hang off the back of the transom? I’m not quite understanding that.
It's not really a stability gain or detriment.
On some hulls it "fools" the hull into thinking it's longer. Other hull just don't run well with them off the transom.
Others, it just doesn't make a difference.
 
That makes sense. I’m assuming the BM sport 40 is one of those hulls that just doesn’t care. The boat above seemed to be doing just fine
 
blazer marine sport 40 i built years ago strut is mounted under the hull as per namba rules. i think it was turning a 447/3 or a 450/2 man this boat was fast...i miss this class.
 
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